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HomeMy WebLinkAbout10 Chapter 6 Performance DataLa Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-1 Chapter 6: Innovative Onsite Wastewater Treatment Systems Introduction One of the primary goals of the La Pine National Demonstration Project is to identify onsite wastewater treatment systems that remove nitrogen from the wastewater prior to dispersal in the environment. The impetus for this task is the shallow unconfined aquifer that is the primary drinking water source for the region. Work performed by the project team to monitor and evaluate groundwater impacts and the fate on contaminants in the environment has shown the vulnerability of this aquifer to discharges from onsite wastewater treatment systems. The performance of the systems participating in the project is therefore presented first in terms of nitrogen reduction and then in terms of other wastewater treatment parameters. The work plan proposed to “install and retrofit 200 or more, if possible, onsite wastewater systems.” Of these, 40 representative systems will be selected for detailed performance analyses. The project ultimately installed 49 systems for detailed performance analyses and, because the lab analyses were significantly more expensive than anticipated at the time of work plan development, the funds for additional installations were limited. Additionally, Oregon rules did not change to facilitate installation of innovative systems at the local level (i.e. without using the more expensive permit process of the Water Pollution Control Facility permit) until 2005 when the La Pine Project was about to close. As a result, funds remaining for additional installations were directed towards use by Deschutes County in implementing a low-interest loan program. Nitrogen-reducing systems The focus of the La Pine Project was nitrogen reduction because of the demonstrated effects of conventional onsite systems on the shallow unconfined aquifer that serves as the region’s drinking water supply. Nitrogen-reducing onsite systems add treatment processes to what is achieved in conventional systems to facilitate the biological processes for nitrogen reduction. These biochemical processes are described in more detail in texts like Burks & Minnis (1994) and Crites & Tchobanoglous (1998). Figure 6-1 provides a simplified illustration of the process steps required to facilitate denitrification. The nitrification and denitrification processes are dependent upon specific chemical and physical conditions in which to occur, including alkalinity, pH, temperature, and dissolved oxygen. For example, the process of transforming ammonium to nitrate (nitrification) consumes alkalinity (measured as CaCO3). Each gram of ammonium transformed to nitrate requires about 7.14g of alkalinity. If enough alkalinity is not present in the wastewater, then the biological process is limited in terms of how much of the ammonium can be converted. Similarly, the biological organisms responsible for converting ammonium to nitrate or nitrate to nitrogen gas (denitrification) are sensitive to the level of dissolved oxygen and/or temperature in the waste stream. If too much dissolved oxygen is available in the denitrification process tank, then the facultative bacteria relied upon for denitrification will preferentially choose the dissolved oxygen for their metabolic processes instead of the oxygen attached to the nitrogen in nitrate (NO3). The balance between the various needs of the biologic organisms used to perform wastewater treatment functions are embodied with the design of the treatment systems and these processes must be understood by any professional seeking to design, install, or maintain a wastewater treatment system appropriate to the needs of the locale. Performance results The performance of the systems participating in the La Pine Project is summarized in Figures 6-2 through 6-7. These charts provide the ranks of all the systems participating in the La Pine Project by Total Nitrogen (TN), 5-day Bio-chemical Oxygen Demand (BOD5), Total Suspended Solids (TSS) and fecal and E. coli bacteria reduction. Each chart also indicates the systems’ performance in relation to the project’s performance criteria for that parameter (Table 6-1). Each chart provides the systems’ rank by mean and median performance of the two or three systems of each type in the study except the bacteria charts, which rank the systems by median and geometric mean performance. The NITREX™ filter is excluded from the TSS and bacteria reduction charts because the lined sand filter preceding the units in this field test significantly influenced the performance of this system for these parameters. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-2 Innovative System Performance Figure 6-1. Wastewater treatment process in nitrogen-reducing systems using (1) the septic tank as an oxygen- poor, carbon-rich environment or (2) a separate process tank with an oxygen-poor, carbon-enriched environment. Table 6-1. La Pine Project performance criteria. Parameter Standard 5-day Bio-chemical Oxygen Demand (BOD5) ≤10 mg/L Total Suspended Solids (TSS) ≤10 mg/L Total Nitrogen (TN) ≤10 mg/L Fecal & E. coli bacteria ≥ 2 log reduction The best performing systems in terms of nitrogen reduction are identified in this section by averaging the data from the field test program to obtain the total nitrogen concentration discharged from the effluent pipe of the treatment unit. Any apparent maturation period data was eliminated from the statistics. These maturation periods, for the purposes of this field test, were identified as those periods at the beginning of system operation when the NH4 concentrations in the effluent declined as nitrate-nitrite (NO3) increased. The systems were considered mature when the treatment process established complete or nearly complete nitrification. The denitrification process may or may not establish itself concurrently or subsequently to the nitrification process depending on the efficacy of the particular system being examined. An example of a system with a clearly defined maturation period without an apparent accompanying denitrification process being established is presented in Figure 6-85. An example of a system that established denitrification after the nitrification process established itself is presented in Figure 6-26. This maturation period also defines the period of evaluation for removal of other parameters of concern (BOD5, TSS, and fecal and E. coli bacteria), which may skew the results for these other parameters because, for example, some systems discharged elevated BOD5 levels for a period after the nitrification or denitrification processes established themselves (Figure 6-80). The TN ranking chart (Figure 6-2) appears to illustrate the challenge faced by denitrifying onsite systems to meet the 10 mg/L performance standard. The one system that consistently met the standard included a secondary carbon source and anoxic environment in which to reduce the nitrate to nitrogen gas. Most of the other systems relied on recirculation to the primary clarifier in order to promote denitrification. The exception is the NiteLess system, which also added a carbon source; the performance of that system is discussed below. Figure 6-3 shows the TN ranking in terms of Total Kjeldahl Nitrogen (TKN) and Nitrate-Nitrite as N (NO3-N) to represent nitrification efficiency. The systems with robust nitrification processes but little denitrification (examples are the sand filters) discharge effluent that is therefore predominantly NO3 within a high overall TN value. The systems that did not La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-3 nitrify well discharged effluent dominated by TKN with a corresponding a high TN value on par or higher than septic tank effluent. The systems that achieved some level of denitrification discharge effluent characterized by a mix of TKN and NO3 and lower overall TN results than the controls (septic tanks and sand filters). In most instances the mean and median TN values reported for the systems in Figure 6-2 are quite similar. The extreme difference between the mean and median for the IDEA system illustrates the variability in those systems’ performance. The mean values plotted in both Figures 6-2 and 6-3 include any adjustment for dilution or evaporation that occurred because the treatment system was open to the environment. The bottomless sand filter column shows the mean TN value above the top of the bar in Figure 6-3 because only the TN value is corrected for dilution, not the individual nitrogen species. The effects of dilution can be corrected by comparing the TN/Cl ratio of the septic tank effluent and to the TN/Cl ratio from the treatment unit discharge pipe. The ratio of these ratios is then multiplied by the average septic tank effluent for the system. In some instances, the correction indicates more nitrogen is discharged from the unit than enters it from the septic tank. This indicates possible concentration of nitrogen due to evaporation or transpiration. The charts providing the BOD5 and TSS ranking (Figures 6-4 and 6-5) summarize the performance of all the participating systems against the performance standard for the field test (10 mg/L). Here, several systems appear capable of achieving good performance in relation to this standard. Here again the median values provide an indication of the variability in performance or extremes in the data produced by each system type. For example, the FAST TSS columns show a high mean TSS value over three systems but a very low median value. This suggests that the data is skewed, and, in review of the data provided in the discussion on the FAST system below (section 7), there is a single extremely high TSS value (2,300 mg/L) that has a significant impact on the calculation of the mean. The standard error bars also provide an indication of the systems’ variability. For example, the standard error of the TSS results for the FAST system is smaller than that for the NiteLess system even though the average TSS discharged for the NiteLess is lower that that of the FAST. In general, the review of both the mean and median values provides the most comprehensive indication of the overall performance of the systems in terms of typical effluent quality and the variability thereof. The TSS chart truncates the upper section of the IDEA mean value from the ranking because the magnitude of this value (1,075 mg/L) obscures the results for the other systems. The performance of the NITREX™ filter for TSS reduction is excluded from this chart because a sand filter precedes the unit and confounds the performance of this unit. Also, the lined sand filter is excluded from the TSS ranking due to problems with obtaining a representative sample for TSS for these systems. The bottomless sand filter data is used as an approximation of the lined sand filter performance. The charts illustrating the bacteria reduction achieved by the systems (Figures 6-6 and 6-7) provide the geometric means and the medians for each system type in order to account for what is the typically highly skewed nature of bacterial data. The charts present the bacteria statistics on a logarithmic scale in order to discern differences between the ranks of the best performing systems. Several systems have shown that they are capable of achieving the two-log reduction contained in the performance standard without an added disinfection process or unit. The performance of the NITREX™ filter is excluded from these charts because a sand filter precedes the unit and the bacteria reduction achieved by the sand filter is very high. While the NITREX™ does achieve an additional level of reduction above that of the sand filter, this product’s overall capacity for reducing bacteria is masked by the performance of the sand filter. The results for phosphorus concentrations discharged from each system are reported in the performance statistics and in the data reported in Appendix B. While the impacts of phosphorus on the water supply aquifer in the La Pine region were not a concern because of the adsorption capacity of the soils in the area, the systems’ performance for this parameter is reported because of the national interest in this nutrient and because of potential exhaustion of the soils’ adsorption capacity in the future. Each system type is discussed in more detail in the sections that follow including basic system design, performance data charted over time, and overall performance statistics. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-4 Innovative System Performance 66.1 61.0 56.5 51.4 51.4 50.2 37.2 36.4 32.3 26.3 18.8 2.4 14.0 17.0 96.8 1.8 14.7 60.8 63.0 61.0 50.2 49.8 51.9 48.0 35.1 34.9 33.5 24.2 16.3 14.1 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 IDEA Septic Tank NiteLess Bottomless Sand Filter Lined Sand Filter Puraflo Dyno2 Nayadic FAST, w/o RV EnviroServer Amphidrome RX-30 AX-20 Biokreisel NITREX mg/L Median Total Nitrogen Mean Total Nitrogen Figure 6-2. Rank, by Total Nitrogen, of all systems in the La Pine Project. 51.4 2.4 51.4 14.0 32.3 50.2 61.0 66.1 56.5 17.0 18.8 37.2 36.4 26.3 96.8 0 102030405060708090100 Lined Sand Filter Bottomless Sand Filter NITREX Puraflo Biokreisel AX-20 RX-30 EnviroServer Nayadic FAST, w/o RV Amphidrome Dyno2 NiteLess Septic Tank IDEA mg/L Total Kjeldahl Nitrogen (mg/L) Nitrate-Nitrite as N (mg/L) Mean Total Nitrogen Figure 6-3. Rank of all systems by Total Nitrogen, including TKN and Nitrate-Nitrite. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-5 2.6 3.0 3.8 13 15 15 18 27 28 28 42 53 122 261 339 1.9 1.5 2.1 5.7 8.0 9.1 9.8 17 18 19 36 32 74 240 66 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 IDEA Septic Tank NiteLess Dyno2 Nayadic EnviroServer Amphidrome FAST, w/o RV NITREX Biokreisel RX-30 AX-20 Lined Sand Filter Bottomless Sand Filter Puraflo mg/L Median BOD-5 (mg/L) Mean BOD-5 (mg/L) Figure 6-4. Rank, by BOD5, of the systems in the La Pine Project. 89 62 27 41 21 11 13 6.0 5.0 4.0 2.0 3.0 94 80 68 46 29 17 15 13 10 9.3 4.7 3.6 8.0 0 102030405060708090100 IDEA Septic Tank Dyno2 FAST NiteLess EnviroServer Nayadic Amphidrome RX-30 Biokreisel AX-20 Bottomless Sand Filter Puraflo mg/L Mean TSS (mg/L) Median TSS (mg/L) 1,075 Figure 6-5. Rank, by Total Suspended Solids, of the systems in the La Pine Project. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-6 Innovative System Performance 1,000,000 186,000 74,000 74,000 12,000 9,900 6,600 5,300 3,400 870 380 195 12 4 10,792,225 231,773 46,647 46,400 13,055 10,275 166,877 17,101 3,600 720 680 267 17 13 1 10 100 1000 10000 100000 1000000 10000000 100000000 IDEA BESTEP Septic Tank Amphidrome NiteLess AX-20 Dyno2 RX-30 FAST, w/o RV EnviroServer Biokreisel Nayadic Puraflo Bottomless Sand Filter Lined Sand Filter log CFU/100 ml Geometric Mean Median Fecal Figure 6-6. Systems ranked by median fecal coliform reduction. 1,000,000 140,000 59,000 42,000 7,800 7,700 5,300 4,400 3,000 480 400 120 8 2 9,463,918 163,501 38,489 17,778 8,332 7,413 59,633 15,324 3,240 460 550 205 14 10 1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 IDEA BESTEP Septic Tank NiteLess Amphidrome AX-20 Dyno2 RX-30 FAST, w/o RV EnviroServer Biokreisel Nayadic Puraflo Bottomless Sand Filter Lined Sand Filter log CFU/100 ml Geometric Mean Median E. coli Figure 6-7. Systems ranked by median E. coli reduction. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-7 (1) AdvanTex™ AX-20, Orenco Systems, Inc. The AX-20 system (http://www.orenco.com/ots/ots_index.asp) uses textile in the packed bed filter as a replacement for sand or gravel. The higher surface area to volume ratio of the textile allows the reduction in size for the textile filter over sand or gravel. The textile is arranged within the filter in hanging sheets (Figure 6-8) and wastewater percolates both through and between the sheets, as the filter is time-dosed. The AX-20 system recirculates effluent to either the primary clarifier or a pump tank. The La Pine Project systems recirculate the effluent to the primary clarifier in order to maximize nitrogen reduction (Mode 3) and each system discharges to a drip distribution field. Sampling locations for this system include the primary clarifier effluent and the textile filter discharge pipe or pump chamber following the discharge pipe. (Figure 6-9) Figures 6-10 through 6-12 show the performance over time of three AX-20 systems in Mode 3. In general, the effluent is nitrified and BOD5 and TSS concentrations are reduced early in the operating period. BOD5 and TSS levels averaged 13 and 9 mg/L respectively over the three systems. (Table 6-2) The median values for BOD5 and TSS were lower, 6 and 4 mg/L respectively, indicating possible outliers in the performance data. However, each system experienced some kind of upset or change in the treatment quality towards the end of the sampling period. Records of field observations during sampling indicate possible operational issues with each system at these times with symptoms of the issues including effluent ponding on the filter sheets, solids sloughing into the pump chamber following the filter and low dissolved oxygen readings. 1MW Figure 6-9. Schematic of AdvanTex™ AX-20 system in Mode 3. Denitrification over the three systems varied somewhat in that TN concentrations from two of the systems averaged between 11 and 17 mg/L (median values were similar to the means) and the third averaged 24 mg/L over the same period. System-T nitrified and otherwise operated similarly to the other two systems but the denitrification process did not respond to the same level. The reason for the difference in performance for the third system was not clear based on homeowner surveys, flow records or system operation. The three systems overall achieved about 1.1 to 1.3 log reduction in fecal and E. coli bacteria based on the geometric means; System-I achieved the best bacteria reduction with a 1.7-1.8-log reduction. This relatively low reduction rate Figure 6-8. AdvanTex™ AX-20 filter media. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-8 Innovative System Performance is possibly due to the large pore spaces present in the textile media, which allow the passage of bacteria while trapping the larger solids. The project team planned to measure flow at each of these residences using an in-line water meter on the pressurized line feeding the drip field. However, this approach produced only an estimate of water use because each time the drip distribution field was dosed there was some return flow to help flush the drip lines. The return flow can cause the meter to run backward and the returned effluent is also pumped forward to the drip field multiple times. While the return flow can be measured and the total calculated, an easier method of measuring flow might be to install the meter on the incoming water line and accounting for irrigation by monitoring water usage during non-irrigation months. System-I AX-20 effluent over time 0 10 20 30 40 50 60 1/23/20023/23/20025/23/20027/23/20029/23/200211/23/20021/23/20033/23/20035/23/20037/23/20039/23/200311/23/20031/23/20043/23/20045/23/20047/23/2004mg/LBOD5 (mg/L) TSS (mg/L) NH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-10. System-I AX-20 (Mode 3) effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-9 0 20 40 60 80 100 120 140 1/23/20023/23/20025/23/20027/23/20029/23/200211/23/20021/23/20033/23/20035/23/20037/23/20039/23/200311/23/20031/23/20043/23/20045/23/20047/23/20049/23/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std BOD5 (mg/L) TSS (mg/L) Figure 6-11. System-T AX-20 (Mode 3) effluent over time. System-M AX-20 effluent over time 0 10 20 30 40 50 60 70 80 90 100 1/8/023/8/025/8/027/8/029/8/0211/8/021/8/033/8/035/8/037/8/039/8/0311/8/031/8/043/8/045/8/047/8/049/8/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std BOD5 (mg/L) TSS (mg/L) Figure 6-12. System-M AX-20 (Mode 3) effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-10 Innovative System Performance Table 6-2. AX-20 performance statistics. All systems AX-20 effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 13 9.3 17 11 5.0E+05 4.2 4.7E+05 3.9 208 Geometric Mean 1.3E+04 4.0 8.3E+03 3.7 Median 5.7 4.0 15 8.8 1.2E+04 4.1 7.8E+03 3.9 232 Standard Deviation 20 15 9.2 19 2.6E+06 1.1 2.7E+06 1.2 102 Minimum ND ND 7.8 2.2 200 2.3 10 1.0 96 Maximum 130 100 44 168 2.2E+07 7.3 2.3E+07 7.4 295 Count 75 75 75 75 75 75 75 75 3 95% Confidence Level 4.6 3.5 2.1 4.4 6.0E+05 0.3 6.2E+05 0.3 253 99% Confidence Level 6.1 4.7 2.8 5.8 8.0E+05 0.3 8.2E+05 0.4 583 System-M AX-20 effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 18 15 11 3.8 4.7E+04 4.2 2.2E+04 3.8 295 Geometric Mean 1.4E+04 4.1 6.4E+03 3.7 Median 11 9.0 9.4 3.4 1.8E+04 4.3 8.7E+03 3.9 300 Standard Deviation 19 19 3.7 2.1 7.1E+04 0.7 4.2E+04 0.7 124 Minimum 1.5 1.0 7.8 2.2 660 2.8 200 2.3 89 Maximum 91 100 24 14 2.7E+05 5.4 1.6E+05 5.2 546 Count 28 28 28 28 28 28 28 28 21 95% Confidence Level 7.4 7.5 1.4 0.8 2.8E+04 0.3 1.6E+04 0.3 57 99% Confidence Level 10 10 1.9 1.1 3.7E+04 0.4 2.2E+04 0.4 77 System-T AX-20 effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 11 7.1 24 8.9 1.4E+06 4.7 1.4E+06 4.6 232 Geometric Mean 5.3E+04 4.5 4.2E+04 4.3 Median 5.1 3.0 23 9.0 4.6E+04 4.7 3.6E+04 4.6 229 Standard Deviation 25 15 8.5 1.0 4.4E+06 1.4 4.6E+06 1.6 39 Minimum ND ND 9.7 7.0 200 2.3 10 1.0 159 Maximum 130 76 39 11 2.2E+07 7.3 2.3E+07 7.4 326 Count 25 25 25 25 25 25 25 25 19 95% Confidence Level 10 6.0 3.5 0.4 1.8E+06 0.6 1.9E+06 0.6 19 99% Confidence Level 14 8.2 4.8 0.6 2.5E+06 0.8 2.6E+06 0.9 26 System-I AX-20 effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 7.7 5.1 17 23 1.9E+04 3.4 1.2E+04 3.3 96 Geometric Mean 3.0E+03 3.4 2.1E+03 3.2 Median 3.5 2.5 15 16 1.6E+03 3.2 1.5E+03 3.2 95 Standard Deviation 12 6.9 9.4 32 5.1E+04 0.8 3.2E+04 0.8 29 Minimum ND ND 8.5 13 240 2.4 140 2.1 25 Maximum 49 27 44 168 2.1E+05 5.3 1.4E+05 5.1 167 Count 22 22 22 22 22 22 22 22 19 95% Confidence Level 5.4 3.0 4.2 14 2.2E+04 0.3 1.4E+04 0.3 14 99% Confidence Level 7.4 4.1 5.7 20 3.1E+04 0.5 1.9E+04 0.5 19 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-11 (2) AdvanTex™ RX-30, Orenco Systems, Inc. The RX-30 system, produced by Orenco Systems, Inc., is a packed bed incorporating a textile material similar to that used in the AX-20. The material is in small pieces approximately the size of a deck of cards and layered within the filter box with a pressure distribution manifold at the top. (Figure 6-13) Denitrification is promoted by recirculating a portion of the effluent to the septic tank. The systems installed for testing in the La Pine Project discharged to shallow gravel-less drainfield (half-pipe over pressurized distribution laterals). Sampling locations for the wastewater system included septic tank effluent and the RX-30 discharge pipe or the pump basin following the discharge pipe. (Figure 6-14) System-M samples for the RX-30 effluent were taken entirely from the pump chamber following the filter due to the low flows received by this system. The performance data over time from the three systems monitored during the field study is presented in Figures 6-15 through 6-17. Each chart contains a distinct maturation period for the system during which the NH4 and TKN levels decline while nitrate-nitrite (NO3) levels rise. Each system also experienced periodic spikes in BOD5 and TSS during the sampling period that appear to be related to operational problems with the system including malfunction or clogging of the splitter valve, clogging within the filter, or possible homeowner abuse of the system by physical damage to components or the use of toxic cleaners within the house. One of the latter occurred at the end of the sampling period of System-R (Figure 6-17) when the nitrification declined and the TN levels increased. This occurred at a point when the sampling team observed that all the effluent samples were blue in color from an every flush toilet bowl cleaner. The homeowner confirmed the use of this product and, upon urging from the vendor, subsequently discontinued its use. Figure 6-14. RX-30 system schematic. Overall, the three systems’ performance approached the La Pine Project criteria for BOD5 and TSS on average after the systems matured. The median values for these parameters met the performance criteria, indicating the data may be skewed by high levels produced within the sampling period. System-H2, Figure 6-15, for example, produced a high level of TSS at the beginning of the sampling period, and, because the maturation period for the systems is defined for the purposes of this study as the time during which the nitrification/denitrification processes are established, the peak TSS value of 260 mg/L is included in the data for the statistics. The effect of this peak on the statistics for System-H2 can be seen in Table 6-4. Figure 6-13. RX-30 textile filter. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-12 Innovative System Performance The three systems appeared to nitrify the effluent well, with most excursions in the nitrification process occurring during the periods when the system experienced an operational upset. For example, during the event at the end of the sampling period for System-R (Figure 6-17) when the homeowner began using every flush toilet bowl cleaner, the NO3 concentrations remain low while the TN and TKN level increase. Because these excursions occur at a time after the systems had already demonstrated their ability to nitrify the effluent, there does not appear to be reason to suspect other limiting factors (ex. alkalinity) to the nitrification process. Bacteria removal in the three systems ranged between 1.7 and 1.8 log reduction and, at first review, the reduction achieved by the systems appears from Table 6-4 to be correlated with flow rate but, when the correlation coefficients are calculated for fecal coliform, the two variables are poorly correlated (Table 6-3). Table 6-3. Correlation coefficients for fecal coliform reduction vs. flow rate in RX-30 systems. Correlation between Fecal Coliform and GPD System-M 0.49 System-R -0.12 System-H2 0.3 System-H2 RX-30 effluent over time 0 10 20 30 40 50 60 70 80 90 100 11/2/19992/2/20005/2/20008/2/200011/2/20002/2/20015/2/20018/2/200111/2/20012/2/20025/2/20028/2/200211/2/20022/2/20035/2/20038/2/2003mg/LNH4-N (mg/L) Nitrate-Nitrite as N (mg/L) TKN TN BOD-5 (mg/l) TSS (mg/L) Performance Standard (260 mg/L) (150 mg/L) Figure 6-15. System-H2 RX-30 effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-13 System-M RX-30 effluent over time 0 10 20 30 40 50 60 70 80 90 100 11/13/20002/13/20015/13/20018/13/200111/13/20012/13/20025/13/20028/13/200211/13/20022/13/20035/13/20038/13/2003mg/LNH4-N (mg/L) Nitrate-Nitrite as N (mg/L) TKN TN BOD-5 (mg/l) TSS (mg/L) Performance Standard (210 mg/L) Figure 6-16. System-M RX-30 effluent over time. System-R RX-30 effluent over time 0 10 20 30 40 50 60 70 80 90 11/13/20002/13/20015/13/20018/13/200111/13/20012/13/20025/13/20028/13/200211/13/20022/13/20035/13/20038/13/2003mg/LNH4-N (mg/L) Nitrate-Nitrite as N (mg/L) TKN TN BOD-5 (mg/l) TSS (mg/L) Performance Standard Figure 6-17. System-R RX-30 effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-14 Innovative System Performance Table 6-4. RX-30 effluent performance statistics. All RX-30 after maturation BOD5 (mg/l) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 15 13 19 12.4 9.0E+05 3.6 2.9E+05 3.4 130 Geometric Mean 1.7E+05 3.4 6.0E+04 3.2 Median 8.0 6.0 16 12 6.6E+03 3.8 5.3E+03 3.7 145 Standard Deviation 18 30 11 3.5 4.0E+06 2.0 1.0E+06 1.8 60 Minimum ND ND 6.1 7.1 ND 0.3 ND 0.3 64 Maximum 90 260 47 22 3.1E+07 7.5 6.4E+06 6.8 181 Count 88 88 88 88 88 88 88 88 3 95% Confidence Level 3.8 6.3 2.2 0.7 8.5E+05 0.4 2.2E+05 0.4 148 99% Confidence Level 5.0 8.4 2.9 1.0 1.1E+06 0.5 2.9E+05 0.5 342 System-M RX-30 after maturation BOD5 (mg/l) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 4.1 5.5 25 14 1.2E+03 1.5 1.5E+03 1.5 64 Geometric Mean 33 1.1 31 1.0 Median 2.8 2.0 27 13 20 1.3 12 1.1 61 Standard Deviation 4.7 15 13 3.9 3.1E+03 1.2 4.1E+03 1.3 17 Minimum ND ND 6.7 9.5 ND 0.3 ND 0.3 26 Maximum 21 82 47 22 1.2E+04 4.1 2.0E+04 4.3 105 Count 29 29 29 29 29 29 29 29 25 95% Confidence Level 1.8 5.7 4.8 1.5 1.2E+03 0.5 1.6E+03 0.5 7 99% Confidence Level 2.4 7.7 6.5 2.0 1.6E+03 0.6 2.1E+03 0.6 10 System-R RX-30 after maturation BOD5 (mg/l) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 16 10 16 13 2.8E+04 3.7 2.7E+04 3.6 145 Geometric Mean 4.9E+03 3.6 4.3E+03 3.5 Median 11 5.0 14 13 5.6E+03 3.7 4.2E+03 3.6 143 Standard Deviation 21 11 9.6 1.9 7.1E+04 0.9 6.7E+04 0.9 28 Minimum ND 1.0 6.1 9.8 26 1.4 12 1.1 84 Maximum 90 44 42 17 3.9E+05 5.6 3.6E+05 5.6 197 Count 31 31 31 31 31 31 31 31 24 95% Confidence Level 7.6 4.2 3.5 0.7 2.6E+04 0.3 2.5E+04 0.3 12 99% Confidence Level 10 5.6 4.7 1.0 3.5E+04 0.4 3.3E+04 0.5 16 System-H2 RX-30 after maturation BOD5 (mg/l) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 23 24 15 9.4 2.8E+06 5.7 8.8E+05 5.2 181 Geometric Mean 5.0E+05 5.6 1.7E+05 5.2 Median 15 12 14 8.7 4.7E+05 5.7 1.8E+05 5.3 176 Standard Deviation 18 48 4.9 2.0 6.8E+06 0.8 1.7E+06 0.9 27 Minimum 2.0 3.0 8.4 7.1 1.6E+04 4.2 5.0E+03 3.7 137 Maximum 64 260 29 16 3.1E+07 7.5 6.4E+06 6.8 242 Count 28 28 28 28 28 28 28 28 22 95% Confidence Level 6.8 18 1.9 0.8 2.6E+06 0.3 6.7E+05 0.3 12 99% Confidence Level 9.2 25 2.6 1.1 3.5E+06 0.4 9.0E+05 0.5 17 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-15 (3) Amphidrome®, FR Mahony & Associates The heart of the Amphidrome® system (Figure 6-18) is deep sand media contained in a vertically oriented tube. This sand bio- reactor is the point at which both oxic and anoxic phases of the nitrification/denitrification treatment processes occur. An underdrain in the bio-reactor structure provides an injection point for both air and water. The air is introduced at the bottom so that it rises and disperses through the sand evenly during the aerobic portion of the process, when the sand media undergoes a vigorous churning action. During this process the sand is churned significantly, creating one of the major differences between this system and a typical packed bed filter. Because of the different phases or conditions existing in the bio-reactor during the treatment process, facultative bacteria that can tolerate the changes provide the treatment. The Amphidrome system sends wastewater forward and backward from the primary clarifier to the clear well through the bio-reactor several times throughout the day. Treated effluent is typically discharged to the dispersal field in a single batch once a day. A more detailed description of the process is available on the FR Mahony and Associates web site at http://www.frmahoney.com/frmahony.htm. A simplified schematic is provided in Figure 6-19. Sampling locations for these systems were limited to the Amphidrome system effluent. The primary clarifier effluent was not sampled because the recirculation in the system took place in batches rather than trickling into the primary clarifier throughout the day. The batch process made obtaining a representative sample from the primary clarifier difficult, therefore, the performance of these systems will be compared to the single-pass septic tanks in the La Pine Project. These systems are evaluated over only two years because of a delayed installation schedule. Figures 6-20 through 6-22 show the effluent quality of three systems over time. Both the nitrogen species and BOD5 and TSS data are shown on each chart. The charts illustrate the initial start up period for the systems, particularly Figures 6-20 and 6-22, when the biota needed for treatment is becoming established in the reactor and while the company adjusted the system settings to work with the flows generated by the household. The system maturation and operational adjustments typically took place within the first 12 months of operation. The length of this “shakedown” period is most likely due to several different factors, including the company being at distance (Massachusetts) and intercultural differences between northeastern and northwestern US modes of communication. In general, once System-AD matured, nitrification appeared to be nearly complete. The other two systems experience significant operational problems including a broken air supply pipe feeding the bio-reactor (System-P) and the large amount of laundry (4 loads/day) done at System-AG, including the use of about 12 cups of liquid fabric softener daily. System-AG has never nitrified the household’s sewage, which may be a result of the toxic effect of the quaternary ammonium compounds in the liquid fabric softener. TN reduction in these systems (Table 6-5) is approximately 50% of the TN discharged by single-pass septic tanks in the La Pine Project based on concentrations. System-AD achieves the best reduction at an average concentration of 17 mg/L. Based on the concentrations, System-AG appears to achieve nearly 50% reduction from septic effluent, however, based on the mass loading produced by this system (34 lb/yr, equivalent to 50 mg/L at 225 gpd), it appears that the high average daily flow received by this system serves to dilute the effluent concentrations. System-AD is close to meeting the BOD5 and TSS performance standard for the La Pine Project. TN exceeds 10 mg/L on average; however, Figure 20 shows that this particular system discharged less than 10 mg/L for certain periods that appear to correlate with the summer months. Due to the shortness of the sampling period it is unclear whether the high effluent quality during the summer months is coincidental or not. Overall, these systems achieved between 1.4 and 1.7 log reduction in fecal and E. coli bacteria, respectively, based on the geometric means. Figure 6-18. Amphidrome system. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-16 Innovative System Performance MW Figure 6-19. Amphidrome schematic. System-AD Amphidrome effluent over time 0 5 10 15 20 25 30 35 40 45 8/27/0210/27/0212/27/022/27/034/27/036/27/038/27/0310/27/0312/27/032/27/044/27/046/27/048/27/0410/27/04mg/LBOD5 (mg/L) TSS (mg/L) NH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-20. System-AD Amphidrome effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-17 System-AG Amphidrome effluent over time 0 20 40 60 80 100 120 140 160 180 10/9/200212/9/20022/9/20034/9/20036/9/20038/9/200310/9/200312/9/20032/9/20044/9/20046/9/20048/9/200410/9/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-21. System-AG Amphidrome effluent over time. System-P Amphidrome effluent over time 0 10 20 30 40 50 60 70 80 7/30/20029/30/200211/30/20021/30/20033/30/20035/30/20037/30/20039/30/200311/30/20031/30/20043/30/20045/30/20047/30/20049/30/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-22. System-P Amphidrome effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-18 Innovative System Performance Table 6-5. Amphidrome performance statistics. All systems' Amphidrome effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 28 15 26 6.4 7.9E+05 4.7 6.6E+05 4.2 167 Geometric Mean 4.7E+04 4.3 1.8E+04 3.6 Median 18 13 24 6.4 7.4E+04 4.9 4.2E+04 4.6 97 Standard Deviation 33 11 14 2.1 2.2E+06 1.4 2.0E+06 1.7 131 Minimum ND ND 6.3 1.8 ND 0.3 ND 0.3 85 Maximum 190 43 63 13 1.1E+07 7.0 9.6E+06 7.0 318 Count 53 53 53 53 51 51 51 51 3 95% Confidence Level 9.2 3.1 4.0 0.6 6.2E+05 0.4 5.5E+05 0.5 326 99% Confidence Level 12 4.1 5.3 0.8 8.3E+05 0.5 7.4E+05 0.6 752 System-P Amphidrome effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 20 17 28 6.8 6.8E+05 4.5 4.8E+05 3.7 97 Geometric Mean 2.9E+04 4.2 5.2E+03 3.0 Median 18 17 21 6.6 6.0E+04 4.8 6.8E+03 3.8 95 Standard Deviation 17 9.3 18 1.7 2.2E+06 1.4 1.8E+06 1.7 39 Minimum ND 3.0 8.8 4.5 38 1.6 ND 0.3 19 Maximum 74 38 63 11 9.6E+06 7.0 7.8E+06 6.9 158 Count 19 19 19 19 19 19 19 19 17 95% Confidence Level 8.0 4.5 8.8 0.8 1.1E+06 0.7 8.6E+05 0.8 20 99% Confidence Level 11 6.1 12 1.1 1.4E+06 1.0 1.2E+06 1.2 28 System-AD Amphidrome effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 13 9.0 17 5.0 1.4E+06 4.9 1.3E+06 4.6 85 Geometric Mean 8.0E+04 4.3 4.4E+04 3.9 Median 11 6.0 18 4.9 1.2E+05 5.1 1.2E+05 5.1 57 Standard Deviation 11 11 7.9 1.6 3.0E+06 1.6 2.8E+06 1.9 91 Minimum 1.6 ND 6.3 1.8 ND 0.3 ND 0.3 13 Maximum 46 43 37 7.4 1.1E+07 7.0 9.6E+06 7.0 360 Count 19 19 18 18 17 17 17 17 17 95% Confidence Level 5.5 5.1 3.9 0.8 1.6E+06 0.8 1.4E+06 1.0 47 99% Confidence Level 7.6 7.0 5.4 1.1 2.1E+06 1.1 2.0E+06 1.3 65 System-AG Amphidrome effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 58 21 34 7.5 2.2E+05 4.6 1.5E+05 4.4 318 Geometric Mean 4.4E+04 4.5 2.5E+04 4.1 Median 42 20 35 7.0 6.8E+04 4.8 4.4E+04 4.6 303 Standard Deviation 47 11 8.7 2.2 3.5E+05 1.1 2.8E+05 1.3 108 Minimum 13 6.0 13 5.1 60 1.8 20 1.3 131 Maximum 190 40 51 13 1.2E+06 6.1 9.8E+05 6.0 525 Count 15 15 16 16 15 15 15 15 17 95% Confidence Level 26 5.9 4.7 1.2 1.9E+05 0.6 1.6E+05 0.7 55 99% Confidence Level 36 8.1 6.4 1.6 2.7E+05 0.9 2.2E+05 1.0 76 La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-19 (4) Biokreisel, Nordbeton, North America, Inc. The heart of the Biokreisel (Figure 6-23) system is a rotating biological contactor turned by a small direct drive motor. The two-chamber unit is bowl shaped to allow solids to settle to the bottom where they can be pumped back to the septic tank (Figure 6- 24). The direct drive motor provides aeration, recirculation and forward flow. The second chamber discharges either to the drainfield or a pump basin as necessary. A small vent, which can be located away from the unit, provides the air required for the process passively. (http://www.nordbeton.co m/biokreiselnna.htm) The La Pine Project installed three Biokreisel systems and monitored them for three years. The sample sites for these systems included the septic tank, the Biokreisel discharge basin, and the pump basin following the gravel polishing filter. Figures 6-25 through 6-27 illustrate the performance of the systems over time. The maturation curve at the start up of the systems is well defined and relatively short. The spike in the BOD5 and TSS within the first year after startup reflects the presence of biological growth in the discharge chamber of the Biokreisel unit observed by the sampling team. The team did not observe this growth again during the sampling period. Overall, the three systems achieve the project performance criteria for BOD5 and TSS and approaches the criteria for TN reduction, averaging 14 mg/L for the three. The fecal and E. coli bacteria reduction, within the unit itself, met the project performance criteria without using the gravel polishing filter installed following the units. (Table 6-6) One unit, System-H shown in Figure 6-27 experienced a malfunction due a failure in the bracket supporting the RBC axle towards the end of the sampling period. The repair, once the replacement parts arrived, took less than a day to complete and the unit appeared to resume functioning as previously. Unfortunately, the sampling period ended before the system’s recovery could be documented. 1Collection ChamberMW Figure 6-24. Biokreisel schematic. Figure 6-23. Biokreisel System. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-20 Innovative System Performance System-M Biokreisel Effluent over time 0 20 40 60 80 100 3/19/20015/19/20017/19/20019/19/200111/19/20011/19/20023/19/20025/19/20027/19/20029/19/200211/19/20021/19/20033/19/20035/19/20037/19/20039/19/2003mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-25. System-M Biokreisel effluent over time. System-G Biokreisel effluent over time 0 20 40 60 80 100 120 140 160 1/3/20013/3/20015/3/20017/3/20019/3/200111/3/20011/3/20023/3/20025/3/20027/3/20029/3/200211/3/20021/3/20033/3/20035/3/20037/3/20039/3/2003mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-26. System-G Biokreisel effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-21 System-H Biokreisel effluent over time 0 10 20 30 40 50 60 70 80 90 1/3/013/3/015/3/017/3/019/3/0111/3/011/3/023/3/025/3/027/3/029/3/0211/3/021/3/033/3/035/3/037/3/039/3/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std RBC malfunction repaired 10/02/03. Final sample taken 10/20/03. RBC malfunction 6/15/03. Figure 6-27. System-H Biokreisel effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-22 Innovative System Performance Table 6-6. Biokreisel performance statistics. All Biokreisel effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. Coli GPD Mean 11 6.1 14 11 8.9E+03 2.9 5.9E+03 2.7 126 Geometric Mean 8.1 5.2 13 11 720 2.6 460 2.4 Median 8.4 5.0 14 9.3 870 2.9 480 2.7 129 Standard Deviation 8.2 3.8 6.8 4.2 2.6E+04 1.1 2.0E+04 1.0 34 Minimum ND ND 4.7 4.5 ND 0.3 ND 0.3 90 Maximum 36 17 56 20 1.6E+05 5.2 1.5E+05 5.2 158 Count 57 56 60 60 60 60 60 60 3 95% Confidence Level 2.2 1.0 1.7 1.1 6.7E+03 0.3 5.3E+03 0.3 84 99% Confidence Level 2.9 1.4 2.3 1.4 8.9E+03 0.4 7.0E+03 0.4 194 System-H Biokreisel effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. Coli GPD Mean 12 5.9 16 16 1.3E+03 2.7 1.0E+03 2.5 158 Geometric Mean 5.9 4.6 14 15 540 2.7 290 2.2 Median 8.2 5.0 14 17 690 2.8 360 2.6 127 Standard Deviation 9.4 4.3 10 3.3 1.7E+03 0.6 1.9E+03 0.8 65 Minimum ND 1.0 7.4 11 18 1.3 ND 0.3 98 Maximum 36 17 56 20 7.0E+03 3.8 8.4E+03 3.9 279 Count 20 20 20 20 20 20 20 20 23 95% Confidence Level 4.4 2.0 4.8 1.6 820 0.3 890 0.4 28 99% Confidence Level 6.0 2.7 6.5 2.1 1.1E+03 0.4 1.2E+03 0.5 38 System-G Biokreisel effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. Coli GPD Mean 7.2 6.1 12 8.1 5.2E+03 2.8 4.7E+03 2.7 129 Geometric Mean 6.5 4.8 12 7.9 550 2.4 460 2.4 Median 5.7 4.0 12 8.3 720 2.9 640 2.8 116 Standard Deviation 4.9 4.2 3.1 1.8 1.0E+04 1.1 1.0E+04 1.1 105 Minimum 2.6 1.0 4.7 4.5 ND 0.3 ND 0.3 38 Maximum 19 14 17 11 3.9E+04 4.6 4.1E+04 4.6 574 Count 18 19 20 20 20 20 20 20 21 95% Confidence Level 2.4 2.0 1.5 0.8 4.8E+03 0.5 4.8E+03 0.5 48 99% Confidence Level 3.3 2.8 2.0 1.1 6.5E+03 0.7 6.6E+03 0.7 65 System-M Biokreisel effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. Coli GPD Mean 14 6.3 14 8.6 2.0E+04 3.1 1.2E+04 2.8 90 Geometric Mean 12 6.2 13 8.5 1.1E+03 2.7 630 2.6 Median 13 6.0 15 8.5 1.5E+03 3.2 610 2.7 94 Standard Deviation 8.2 3.0 4.6 1.4 4.2E+04 1.3 3.4E+04 1.2 27 Minimum 1.6 0.5 4.8 5.0 10 1.0 14 1.1 48 Maximum 31 14 23 11 1.6E+05 5.2 1.5E+05 5.2 150 Count 19 17 20 20 20 20 20 20 16 95% Confidence Level 4.0 1.6 2.2 0.7 2.0E+04 0.6 1.6E+04 0.6 14 99% Confidence Level 5.4 2.1 2.9 0.9 2.7E+04 0.8 2.1E+04 0.8 20 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-23 Figure 6-28. Dyno2 vertical flow wetland. (5) Dyno2™, North American Wetlands Engineering / Reactor Dynamics, Inc. The core of the Dyno2 treatment process consists of a recirculating gravel filter combined with wetland treatment system components. North American Wetlands Engineering (now Jacques Whitford NAWE) (http://www.nawe- pa.com) produces this system out of Minnesota in a seven-foot tall tank that arrives pre-packed with the manufactured gravel media, plants and other system components. The tank is delivered in two parts and is assembled on the site. (Figure 6-28). A two- compartment single-pass septic tank provides primary treatment before the effluent passes through the attached growth media in the influent chamber of the Dyno2. Sampling locations for this system include the septic tank and the pump chamber. (Figure 6-29) The performance of the three units over time is presented in Figures 6-30 through 6- 33. Figure 6-31 shows that System-C operated for an extended period during the field test where the system does not nitrify the effluent. During this period, the alkalinity levels are sufficient to support the process (average NH4 = 31 mg/L’ Total Alkalinity = 261 mg/L; Alkalinity needed to nitrify = 224 mg/L) but the dissolved oxygen levels are low (mean = 1.7 mg/L, median = 0.9 mg/L). The vendor discovered that the wetland underdrain pipe had been capped and all the effluent directed to the drainfield without recirculating as designed. The system had been installed and started up properly based on the vendor’s inspection at the time; the party responsible for this modification to the system is unknown. Figure 6-29. Dyno2 schematic. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-24 Innovative System Performance The vendor’s designated maintenance provider repaired System-C in October 2003, at which point the system began nitrifying and the TN levels appear to decline. The TSS levels (and BOD5 levels to a lesser degree) spike towards the end of the sampling period beginning in June 2004 (peak TSS = 740 mg/L). The sampling team observed at this time that the effluent was grayish white in color. Because the house was undergoing a significant addition and remodel during the sampling period, the sampling field notes suggested that the color may be due to the presence of paint or plaster in the effluent. In general, the first year of operation of the other two systems appears quite variable. The vendor found that the water level sensors in all the systems were faulty and that the control panels originally installed for the systems would not allow the recirculation ratios to be lowered sufficiently to work with the flows from some of these households. The company replaced the control panels and the sensors, which appears to have resulted in improved performance, particularly for System-E (Figure 6-32). System-N performance does not appear to change much with the recirculation adjustments. This particular homeowner complained that he often had to clean the effluent filter because of frequent alarms. The observations noted by the sampling team for this system also indicated the presence of solids or particulate matter in the effluent of this system from the time it was installed. One of the final field observations noted by the sampling team was the blue color of all the effluent samples. The homeowner subsequently confirmed the use of an every flush toilet bowl cleaner/deodorizer in the house. To further confound the issue, the vendor discovered that the homeowner had moved the unit off of its dedicated circuit in the breaker box to a lower amperage circuit at some point in the previous eight months or so. Otherwise, it is unclear what may have caused the presence of the solids in the effluent and the frequent clogging of the effluent filter for this system from the time the system began operation. Overall, the performance of these systems has not met the field test standards. (Table 6-7) The BOD5 reduction is significantly better than septic tank effluent but the TSS levels discharged by the systems are still high, which could be a concern for the long-term health of the drainfields, particularly if the recirculation process fails to keep high levels of dissolved oxygen in the effluent. The TN reductions of the three systems do not meet the project’s performance standards. System-C’s ability to denitrify is impaired by the lack of nitrification in. The causes for the lack of reduction in the other systems are not as clear and the best performing system of this type achieves approximately a 50% reduction. The Total Phosphorus statistics provided in Table 6-7 (mean = 9.4 mg/L) indicate that little or no phosphorus reduction occurs in this system. The manufactured aggregate used for the recirculating gravel filter apparently has little capacity for adsorbing phosphorus because the average phosphorus discharged from the septic tanks was 10.5 mg/L. This value and that discharged from the treatment unit are statistically identical at the 99% confidence level. The dilution calculations for System-C appear questionable in that the calculated result for TN is 145 mg/L on average. The median value for this system is 60 mg/L, which is more consistent with the uncorrected TN concentrations discharged from this system. Possible explanations for the variance in results include a high level of evaporation experienced by this system because of the low flows (60 GPD on average) which would then concentrate the TN in the effluent. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-25 System-C Dyno2 effluent nitrogen species over time 0 10 20 30 40 50 60 70 80 90 1/7/023/7/025/7/027/7/029/7/0211/7/021/7/033/7/035/7/037/7/039/7/0311/7/031/7/043/7/045/7/047/7/049/7/0411/7/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-30. System-C Dyno2 effluent nitrogen species over time. System-C Dyno2 effluent BOD/TSS over time 0 100 200 300 400 500 600 700 800 1/7/023/7/025/7/027/7/029/7/0211/7/021/7/033/7/035/7/037/7/039/7/0311/7/031/7/043/7/045/7/047/7/049/7/0411/7/04mg/LPerformance Std BOD5 (mg/L) TSS (mg/L) Figure 6-31. System-C Dyno2 effluent BOD5/TSS over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-26 Innovative System Performance System-E Dyno2 effluent over time 0 20 40 60 80 100 120 140 1/28/023/28/025/28/027/28/029/28/0211/28/021/28/033/28/035/28/037/28/039/28/0311/28/031/28/043/28/045/28/047/28/049/28/0411/28/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std (BOD = 230 mg/L, TSS = 320/440 mg/L)(BOD = 230 mg/L) Figure 6-32. System-E Dyno2 effluent over time. System-N Dyno2 effluent over time 0 50 100 150 200 250 300 350 1/22/023/22/025/22/027/22/029/22/0211/22/021/22/033/22/035/22/037/22/039/22/0311/22/031/22/043/22/045/22/047/22/049/22/0411/22/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std (870 mg/L) Figure 6-33. System-N Dyno2 effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-27 Table 6-7. Dyno2 performance statistics. All Dyno2 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 53 80 50 87 9.4 3.3E+06 4.1 2.0E+06 3.9 102 Geometric Mean 1.0E+04 3.5 7.4E+03 3.3 Median 32 27 48 55 9.8 9.9E+03 4.0 7.7E+03 3.9 81 Standard Deviation 58 145 23 219 3.9 1.6E+07 1.7 1.1E+07 1.8 64 Minimum 1.5 1.0 10 14 0.3 ND 0.3 ND 0.3 10 Maximum 350 870 125 1759 19 1.0E+08 8 9.5E+07 8.0 259 Count 83 83 80 61 82 84 84 84 84 47 95% Confidence Level 13 32 5.0 56 0.8 3.4E+06 0.4 2.3E+06 0.4 19 99% Confidence Level 17 42 6.7 75 1.1 4.5E+06 0.5 3.1E+06 0.5 25 System-C Dyno2 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 42 72 48 145 6.1 4.4E+03 2.5 4.7E+03 2.5 61 Geometric Mean 304 2.0 283 1.9 Median 32 20 46 60 6.2 150 2.2 150 2.2 57 Standard Deviation 36 156 21 380 3.7 8.2E+03 1.4 1.0E+04 1.3 41 Minimum 3.5 3.0 10 36 0.3 ND 0.3 ND 0.3 10 Maximum 150 740 77 1759 13 3.2E+04 4.5 4.6E+04 4.7 162 Count 27 27 26 20 27 27 27 27 27 16 95% Confidence Level 14 62 8.7 178 1.5 3.3E+03 0.5 4.1E+03 0.5 22 99% Confidence Level 19 83 12 243 2.0 4.4E+03 0.7 5.6E+03 0.7 30 System-E Dyno2 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 61 56 35 38 10 9.2E+06 5.4 5.6E+06 5.3 174 Geometric Mean 2.6E+05 5.2 2.0E+05 5.1 Median 28 27 34 40 10 5.4E+05 5.7 3.4E+05 5.5 176 Standard Deviation 66 95 11 13 1.3 2.5E+07 1.4 1.8E+07 1.4 45 Minimum 1.5 2.0 19 14 8.0 1.3E+03 3.1 1.2E+03 3.1 98 Maximum 230 440 55 61 14 1.0E+08 8 9.5E+07 8.0 259 Count 29 29 29 21 29 30 30 30 30 16 95% Confidence Level 25 36 4.2 5.9 0.5 9.5E+06 0.5 6.6E+06 0.5 24 99% Confidence Level 34 49 5.7 8.0 0.7 1.3E+07 0.7 8.9E+06 0.7 33 System-N Dyno2 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 55 114 70 81 12 1.1E+05 4.1 8.1E+04 3.9 69 Geometric Mean 1.4E+04 4.0 7.1E+03 3.6 Median 33 35 69 87 12 1.1E+04 4.0 7.0E+03 3.8 66 Standard Deviation 68 175 20 26 3.6 2.2E+05 1.0 1.7E+05 1.2 22 Minimum 2.6 1.0 34 35 5.0 120 2.1 20 1.3 32 Maximum 350 870 125 141 19 7.6E+05 5.9 7.0E+05 5.8 134 Count 27 27 25 20 26 27 27 27 27 15 95% Confidence Level 27 69 8.4 12 1.5 8.7E+04 0.4 6.7E+04 0.5 12 99% Confidence Level 36 93 11 16 2.0 1.2E+05 0.6 9.1E+04 0.6 17 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-28 Innovative System Performance (6) EnviroServer, MicroSepTec, Inc. The EnviroServer system (Figure 6-34) includes both fixed film and suspended growth processes in a forced aeration wastewater treatment system. This system recirculates to the primary clarifier to promote denitrification and the two units installed in the La Pine region included thermal processors to remove sludge from the primary compartment to eliminate the need for pumping. The disinfection units (chlorine tablet dispensers) were not used in the demonstration project in order to define the bacterial reduction achieved by the unit. The systems originally discharged to drip distribution fields (Figure 6-35); however, these fields were replaced by the end of the project due to clogging in the drip field and each system now pumps to a distribution box that discharges to a gravity drainfield. Details on this system are available on the company’s website at: http://www.microseptec.com/. Figure 6-34. MicroSepTec EnviroServer. The performance data shown in Figure 6-36 and 6-37 indicate the effluent is generally well nitrified over the sampling period whereas the denitrification rates varied over time. In general, System-M (Figure 6-37) does not nitrify the effluent as completely as System-H does (Figure 6-36). The dissolved oxygen concentrations in the effluent indicate they are sufficient (mean DO = 3.6 mg/L) for the aerobic process. A comparison of the available alkalinity in the effluent versus the ammonium concentrations suggests that the nitrifications process is alkalinity- limited. (Mean alkalinity = 37 mg/L, calculated mean alkalinity needed = 64 mg/L) This limitation may also explain the slightly lower pH in System-M effluent (mean pH = 6.7) than in System-H (mean pH = 7.7). (The difference between these means is statistically significant to the 99% confidence interval.) The pH values are consistent with the theory that the system is alkalinity-limited because the consumption of alkalinity during the nitrification process reduces the buffering capacity in the effluent, which can cause the effluent to become acidic and therefore inhibit the action of nitrifying bacteria. (Burks & Minnis, 1994) And, if nitrification processes are limited, then the denitrification processes are necessarily limited. System-M is one of the few systems in the La Pine Project in which the nitrification process appears to be alkalinity limited. System-M shows relatively good performance for BOD5 and TSS reduction after the startup period. The high means calculated (Table 6-8) for this system reflect the inclusion of some of the initial high values and a spike almost a year after start of sampling. The medians reported may be a more accurate representation of this system’s performance because of the skewing effect of those two events. The BOD5 and TSS results for System-H indicate variability in its performance, which may indicate a cause for the drip field failure. The highest values shown for TSS on the chart correspond to a period during which the homeowners complained about the maintenance provider or the project sampling staff closing a particular valve. Whenever they noticed this valve closed, they would open it, believing that they understood how the system was supposed to operate. The valve was the drip field flush valve La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-29 that the system designer intended to be closed during normal operations and only used during maintenance procedures. As a result, it appears that the more frequent and higher volume return flow from the drip field disrupted the primary clarifier and could account for the higher TSS values reported. (Table 6-8) Although the median values for TSS are lower than the means over the two systems, indicating the effect of the high values, the systems did not meet the project’s performance criterion for TSS. Over all the parameters, the performance of the two systems did not meet any of the project’s performance criteria except for bacteria reduction (log reduction between 2.6 and 2.7). Power consumption for the unit has been a concern voiced by the homeowners because of the blowers, multiple pumps and pyrolytic converter. Based on the manufacturer’s reported energy use rate for the system of 6 kWh/day and the delivery rate of electricity in the La Pine area, the calculated electricity cost ranges between $10 and $15 dollars per month to operate the system. Table 6-8. EnviroServer performance statistics. All EnviroServer effluent (ESE) after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 28 29 32 9.1 9.7E+03 3.5 8.1E+03 3.5 164 Geometric Mean 31 3.6E+03 3.5 3.2E+03 3.4 Median 19 21 34 8.6 3.4E+03 3.5 3.0E+03 3.5 158 Standard Deviation 32 24 11 1.5 1.9E+04 0.6 1.4E+04 0.6 81 Minimum 1.9 4.0 8.3 6.7 140 2.1 98 2.0 28 Maximum 174 110 56 14 1.0E+05 5.0 6.9E+04 4.8 440 Count 58 58 58 58 58 58 58 58 39 95% Confidence Level 8.4 6.4 3.0 0.4 5.1E+03 0.2 3.7E+03 0.2 26 99% Confidence Level 11 8.5 4.0 0.5 6.8E+03 0.2 5.0E+03 0.2 35 System-M ESE after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 37 27 40 10 1.1E+04 3.3 8.7E+03 3.3 140 Geometric Mean 39 2.2E+03 3.3 1.9E+03 3.2 Median 22 21 38 9.9 1.7E+03 3.2 1.3E+03 3.1 148 Standard Deviation 41 18 8.3 1.5 2.6E+04 0.7 1.8E+04 0.7 53 Minimum 2.4 4.0 23 7.9 140 2.1 98 2.0 34 Maximum 174 72 56 14 1.0E+05 5.0 6.9E+04 4.8 237 Count 30 30 30 30 30 30 30 30 19 95% Confidence Level 15 6.7 3.1 0.6 9.7E+03 0.3 6.7E+03 0.3 26 99% Confidence Level 21 9.0 4.2 0.8 1.3E+04 0.4 9030 0.4 35 System-H ESE after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 19 32 24 8.2 8.2E+03 3.7 7.4E+03 3.7 188 Geometric Mean 23 5.1E+03 3.7 4.6E+03 3.6 Median 15 22 25 8.1 6.8E+03 3.8 6.2E+03 3.8 180 Standard Deviation 13 30 8.4 0.8 8.7E+03 0.5 9.0E+03 0.5 96 Minimum 1.9 6.0 8.3 6.7 680 2.8 520 2.7 28 Maximum 45 110 36 11 4.0E+04 4.6 4.6E+04 4.7 440 Count 28 28 28 28 28 28 28 28 20 95% Confidence Level 4.9 12 3.3 0.3 3.4E+03 0.2 3.5E+03 0.2 45 99% Confidence Level 6.7 16 4.4 0.4 4.5E+03 0.2 4.7E+03 0.2 61 La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-30 Innovative System Performance Figure 6-35. EnviroServer schematic. System-H EnviroServer effluent over time 0 20 40 60 80 100 120 7/30/019/30/0111/30/011/30/023/30/025/30/027/30/029/30/0211/30/021/30/033/30/035/30/037/30/039/30/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Standard Figure 6-36. System-H EnviroServer effluent quality over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-31 System-M EnviroServer effluent over time 0 20 40 60 80 100 120 140 160 180 7/30/019/30/0111/30/011/30/023/30/025/30/027/30/029/30/0211/30/021/30/033/30/035/30/037/30/039/30/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Standard Figure 6-37. System-M EnviroServer effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-32 Innovative System Performance (7) MicroFAST® Wastewater Treatment System, Bio-Microbics, Inc., The MicroFAST (Fixed Activated Sludge Treatment) system (Figure 6-38, http://www.biomicrobics.com/) uses both attached and suspended growth processes in a unit that combines a packed bed approach with forced aeration. The honeycomb filter media provides a surface for attached growth in addition to the clear space for the activated sludge process. The quiescent areas in the tank surrounding the aeration unit are suboxic and rich in organic material to facilitate denitrification. The typical residential installation in the La Pine Project uses a two- compartment 1,500-gallon tank with the MicroFAST unit in the larger side. The house effluent sewer pipe discharges to the small (500 gallon) trash tank to provide minimal primary treatment before the wastewater enters the aeration chamber. The unit can either discharge to a gravity fed dispersal field or a pump chamber. The installations for the La Pine Project discharged to a pressurized drainfield in order to use an in-line water meter as a flow-measuring device. The effluent data over time for the three systems installed and monitored are provided in Figures 6-40 through 6-42. In all cases, the BOD5 and TSS are provided in the same figure as the nitrogen species and the project performance criteria of 10 mg/L for these parameters is indicated. System-R (Figure 6-40 shows good nitrification over the majority of the sampling period. The nitrification declines at the end of the record at a time when the sampling team observed that the blower was not operating when they arrived on the site. The unit began operating shortly after the homeowner returned to the house after greeting the team. It is not clear from the record whether the unit was cycling on and off based on control panel settings or if the homeowner was turning the unit off manually. Regardless of the cause for the system operating in this manner, the nitrifying bacteria are sensitive to dissolved oxygen concentrations in the effluent and the NO3 concentrations in the effluent decline significantly for the duration of the record. Additionally, during this period, the field observations and homeowner surveys include other circumstances that could adversely impact system performance. These include the use of every flush toilet bowl deodorizers and the need for tank pumping. The high TSS value recorded for System-R (2,300 mg/L) has no apparent explanation based on field observations or lab records. When this value is omitted from the statistics, the resulting mean, 18 mg/L, is significantly lower. The median value calculated with the outlier included (5 mg/L, versus the mean, 129 mg/L) also shows the impact of this outlier on the statistics for System-R. This situation illustrates the usefulness of the median value in indicating how large outliers in the data may skew averages. (Table 6-9) System-J (Figure 6-41) discharged high levels of TN over the sampling period. This system served a recreational vehicle (RV) in which the property owners lived while they built their permanent residence on the site. The owners were very cooperative and did not use any holding tank chemicals or enzymes in the RV and called with specific questions about the kinds of activities their system could handle (for example, one call included a question about where to wash out paint brushes). The RV drained to a 50- gallon tank where a sewage ejector pump macerated the effluent and discharged it to the MicroFAST system via a 100 foot-long transport pipe. This setup caused two significant impacts to the FAST system in that the slug flow disrupted the primary treatment process and caused short-circuiting in the MicroFAST unit and the effluent cooled significantly. The sampling team observed the physical disruption of the tank when the pump discharged the tank’s contents. The mixing and pushing action disturbed the action of the trash tank and the MicroFAST unit whether the dose contained sewage or not (ex. laundry discharge). The mean trash tank temperature was 12 ºC and the recorded values ranged between a low of 5ºC in the winter to a high of 20 ºC in the summer. The population of 20 septic tanks monitored as part of the La Pine Project discharged effluent that was 15 ºC on average; the difference between the mean temperatures is significant to the 99% confidence level. Low wastewater temperatures can have a negative impact on the efficiency of the microbial populations relied upon to treat the effluent. Figure 6-38. Bio-Microbics, Inc. FAST® system. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-33 The overall BOD5 reduction in System-J averages 85% based on the La Pine Project septic tank population. The reduction based on the trash tank effluent quality (BOD5 mean = 430 mg/L) averages 91%. Performing an analysis of system performance in this manner highlights the potential difficulties related to a performance standard based on percent reduction alone. The performance chart for System-P (Figure 6-42) shows a system experiencing a high level of variability in effluent quality over the sampling period. The system appears to have difficulties completely nitrifying the effluent and nitrification appears to stop almost entirely during the final 10 months of the record. Alkalinity in the effluent does not appear to be a significant limiting factor because the average alkalinity concentration equals 119 mg/L and the average alkalinity demand is 133 mg/L (the difference between the means is not statistically significant at the 99% confidence level). Dissolved oxygen levels also do not appear to be a limitation because average concentrations are 3.5 mg/L and range between 1.2 and 5.3 mg/L. The homeowner surveys do not indicate the use of liquid fabric softeners, anti-bacterial cleaning products, every flush toilet bowl cleaners, or prescription medications/antibiotics. It is unclear from field and other data and observations what caused the system to perform in this manner. Figure 6-39. MicroFAST system schematic. Overall, the three systems do not meet the project’s performance criteria. TN from the three units (mean = 48 mg/L, median = 38 mg/L) indicates a 28 to 39% reduction from the project’s septic tank effluent data (Table 5-1). In terms of mass loading, the effects of low water use can be detected in System-J (the RV site) where, if the mass load of TN generated by this household is applied using an average flow rate of 225 GPD, the average concentration would be 35 mg/L instead of 70 mg/L. On average, the systems achieve a 1.6 log bacteria reduction overall with performance varying between 1 and 2.3 log reduction in individual systems. The BOD5 and TSS reductions approach NSF standard 40 criteria, particularly when the medians are considered (to remove the effects of outliers in the data). La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-34 Innovative System Performance Table 6-9. MicroFAST® system performance statistics. All Systems after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 30 58 48 10 9.0E+04 3.8 6.8E+04 3.7 166 Geometric Mean 6.0E+03 3.6 5.4E+03 3.5 Median 38 29 38 11 2.7E+04 3.9 2.5E+04 3.9 162 Standard Deviation 16 62 19 2.3 1.3E+05 0.7 9.3E+04 0.7 56 Minimum 12 15 35 7.5 4.7E+03 3.0 4.1E+03 3.0 112 Maximum 41 129 70 12 2.4E+05 4.4 1.7E+05 4.4 224 Count 3 3 3 3 3 3 3 3 3 95% Confidence Level 40 154 47 5.7 3.2E+05 1.7 2.3E+05 1.8 139 99% Confidence Level 91 355 110 13 7.3E+05 3.9 5.3E+05 4.1 322 System-J FAST Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 38 29 70 12 2.4E+05 4.4 1.7E+05 4.4 112 Geometric Mean 2.6E+04 4.3 2.4E+04 4.3 Median 35 31 69 13 1.2E+04 4.1 1.3E+04 4.1 110 Standard Deviation 24 17 21 2.9 4.0E+05 1.1 2.9E+05 1.0 54 Minimum 10 4.0 24 3.7 400 2.6 400 2.6 30 Maximum 110 68 100 15 1.3E+06 6.1 9.5E+05 6.0 229 Count 22 22 22 22 22 22 22 22 18 95% Confidence Level 11 7.4 9.2 1.3 1.8E+05 0.5 1.3E+05 0.5 27 99% Confidence Level 14 10 12 1.8 2.4E+05 0.6 1.8E+05 0.6 37 System-P FAST Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 41 15 35 11 2.7E+04 3.9 2.5E+04 3.9 224 Geometric Mean 7.7E+03 3.7 7.2E+03 3.7 Median 32 13 34 11 1.1E+04 4.0 9.6E+03 4.0 207 Standard Deviation 36 9.0 10 1.2 3.2E+04 1.0 2.8E+04 0.9 74 Minimum 3.5 2.0 17 8.6 49 1.7 69 1.8 132 Maximum 170 32 54 14 1.0E+05 5.0 8.8E+04 4.9 478 Count 22 22 22 22 22 22 22 22 21 95% Confidence Level 16 4.0 4.5 0.5 1.4E+04 0.4 1.2E+04 0.4 34 99% Confidence Level 22 5.4 6.2 0.7 1.9E+04 0.6 1.7E+04 0.6 46 System-R FAST Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 12 129 38 7.5 4.7E+03 3.0 4.1E+03 3.0 162 Geometric Mean 1.1E+03 2.9 913 2.8 Median 12 5.0 39 7.4 1.4E+03 3.1 1.3E+03 3.1 161 Standard Deviation 7.4 526 10 1.9 6.6E+03 0.9 6.8E+03 0.9 42 Minimum 1.3 1.0 22 3.4 40 1.6 32 1.5 47 Maximum 29 2300 57 11 2.5E+04 4.4 2.8E+04 4.4 232 Count 19 19 19 19 18 18 18 18 20 95% Confidence Level 3.6 254 4.8 0.9 3.3E+03 0.5 3.4E+03 0.5 20 99% Confidence Level 4.9 347 6.5 1.3 4.5E+03 0.6 4.7E+03 0.6 27 La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-35 System-R FAST effluent over time 0 10 20 30 40 50 60 12/17/012/17/024/17/026/17/028/17/0210/17/0212/17/022/17/034/17/036/17/038/17/0310/17/0312/17/032/17/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std (2300 mg/L) Figure 6-40. System-R FAST® effluent over time. System-J FAST effluent over time 0 20 40 60 80 100 120 1/22/023/22/025/22/027/22/029/22/0211/22/021/22/033/22/035/22/037/22/039/22/0311/22/031/22/043/22/04mg/LBOD5 (mg/L) TSS (mg/L) NH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-41. System-J FAST effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-36 Innovative System Performance System-P FAST effluent over time 0 10 20 30 40 50 60 70 80 2/7/014/7/016/7/018/7/0110/7/0112/7/012/7/024/7/026/7/028/7/0210/7/0212/7/022/7/034/7/036/7/038/7/0310/7/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std (170 mg/L) (95/94 mg/L) Figure 6-42. System-P FAST effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-37 (8) IDEA BESTEP, Advanced Environmental Systems, Inc. The IDEA BESTEP system (Figure 6-43) is produced by Advanced Environmental Systems, Inc. of Sparks, Nevada (http://www.aeswastewater.com/). This system is a sequencing batch reactor where the entire treatment process (suspended growth activated sludge) takes place within a single tank. The aeration, settling, and decant phases occur throughout the day with continuous feed to the inlet portion of the processing tank. The systems installed in the La Pine Project decanted to distribution boxes, which then discharged to the dispersal fields. The sampling team took system effluent samples from the distribution box in order to best represent the effluent quality discharged to the dispersal fields. The performance of these systems will be compared to the single-pass septic tanks in the La Pine Project because the systems do not include a septic tank or primary processing tank. Figure 6-43. IDEA system process schematic. The performance of these systems over time is shown in the performance charts (Figures 6-45 through 6-48). Figures 6-46 through 6-48 provide a clearer view of the performance of the systems with the extreme high values truncated on the chart. Table 6-11 provides the performance statistics for the three systems installed for the La Pine Project. Overall, the mean BOD5 performance is comparable to the single-pass septic tanks sampled in the project (Table 5-1). The lower median values reported indicate that the data is skewed by instances of high TSS in the effluent. While each system participating in the La Pine Project experienced some outliers in the performance data, the magnitude of the extremes in these systems is of concern. The TSS statistics in Table 6-11 and illustrated in the performance charts indicates an average performance that is between 5 and 23 times worse than average septic tank performance. One system discharged a high of 27,000 mg/L TSS that, based on field observations during that sampling event, is an accurate representation of what the dispersal field received during that event. Figure 6-44. TSS samples from the IDEA system. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-38 Innovative System Performance The other two systems’ water quality data did not produce this magnitude of result; however, the sample record shows highs of 4,300 and 4,600 mg/L discharged by the other systems that are also corroborated by field observations. (Figure 6-44) The nitrogen results for each system indicate a similar variability in performance over the three systems. The total nitrogen typically exceeds that discharged by the septic tanks in the project with maximum reported values ranging between 250 and 1,400 mg/L. Figure 6-3 and the performance charts indicate that the process did not nitrify the effluent consistently. Given that 7.14 mg/L of alkalinity is required to nitrify 1 mg/L of NH4 (Burks and Minnis, 1994) and based on the amount of NH4 (ammonium) present in the IDEA effluent, the systems, on average, appear to have sufficient alkalinity present to nitrify most of the ammonium present (Table 6-10). However, if the balance of the TKN present in the effluent that is organic nitrogen (96 mg/L) is converted to NH4, then the alkalinity demand would approximately triple and far exceed what is available in the effluent. It appears that the nitrification process is also, and perhaps predominantly, hindered by the conversion of organic nitrogen to ammonium because ammonium comprises only 32% of the TKN on average in the system effluent. This limitation would then in turn limit the conversion of ammonium to nitrate regardless of the amount of alkalinity available to support the nitrification process. Table 6-10. Estimated alkalinity requirements indicated by IDEA effluent quality. Average alkalinity requirements in three IDEA systems Total Alkalinity present in IDEA effluent (mg/L) Alkalinity required based on NH4 present in IDEA effluent Maximum alkalinity required for process based on TKN present in IDEA effluent Mean 245 221 691 Median 200 143 434 Standard Deviation 134 235 1478 Minimum 74 0.5 26 Maximum 569 728 9996 The bacteria levels discharged by these systems exceed the average values discharged by single-pass septic tanks in the La Pine Project. The system also discharged significantly more total phosphorus than single-pass septic tanks. The suspended growth activated sludge process incorporated in this system appears to create the condition where more of the tanks contents can be discharged if the system malfunctions and consequently have greater environmental impacts than a conventional onsite system. The vendor did not install any flow measuring devices in the control panel or in the discharge line so accurate mass loading calculations are not possible for these systems. However, if the mass load is calculated for the single maximum TSS value reported of 27,000 mg/L (~50 lb/day using an average design flow of 225 GPD), then this single discharge is the equivalent of a system discharging 150 mg/L TSS at 225 GPD for 180 days. (This calculation assumes that the system’s effluent contained 27,000 mg/L for a 24-hour period.) Given the implications that these types of discharges have for the design life of a soil absorption system and the observed ponding in the trenches in each system within a year to a year and a half after start up, the project team decided to halt testing on these systems six months early and replace the treatment units. Technically, the outliers in the data could be removed from the statistics for these systems, but the project team felt that the magnitude of the outliers created a significant impact on the performance of the soil absorption field. In this case, the project team were concerned that the effects of the outlier were actually significant and could not be removed from the dataset. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-39 System-H IDEA EFfluent Nitrogen Species over time 0 200 400 600 800 1000 1200 1400 1/7/022/7/023/7/024/7/025/7/026/7/027/7/028/7/029/7/0210/7/0211/7/0212/7/021/7/032/7/033/7/034/7/035/7/036/7/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Figure 6-45. System-H IDEA effluent nitrogen species over time. System-H IDEA effluent over time 0 20 40 60 80 100 120 140 160 180 200 1/7/20022/7/20023/7/20024/7/20025/7/20026/7/20027/7/20028/7/20029/7/200210/7/200211/7/200212/7/20021/7/20032/7/20033/7/20034/7/20035/7/20036/7/2003mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-46. System-H IDEA effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-40 Innovative System Performance System-L IDEA effluent over time 0 10 20 30 40 50 60 70 80 90 100 1/7/022/7/023/7/024/7/025/7/026/7/027/7/028/7/029/7/0210/7/0211/7/0212/7/021/7/032/7/033/7/034/7/035/7/036/7/037/7/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std TSS (mg/L) BOD5 (mg/L) Figure 6-47. System-L IDEA effluent over time. System-Y IDEA effluent over time 0 50 100 150 200 250 300 2/11/20023/11/20024/11/20025/11/20026/11/20027/11/20028/11/20029/11/200210/11/200211/11/200212/11/20021/11/20032/11/20033/11/20034/11/20035/11/20036/11/20037/11/2003mg/LNH4 As N (mg/L) TKN (mg/L) Nitrate-Nitrite As N (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-48. System-Y IDEA effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-41 Table 6-11. IDEA BESTEP performance statistics. All IDEA effluent (no apparent maturation periods) BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 340 1,075 97 25 7.6E+07 5.9 7.2E+07 5.9 N/A Geometric Mean 1.1E+07 5.8 9.5E+06 5.7 Median 66 89 61 15 1.0E+06 6.0 1.0E+06 6.0 Standard Deviation 765 4,090 207 52 2.6E+08 1.8 2.5E+08 1.8 Minimum 3.1 2.0 3.7 0.5 200 2.3 200 2.3 Maximum 4,600 27,000 1,400 352 1.6E+09 9.2 1.6E+09 9.2 Count 45 45 46 46 45 45 45 45 95% Confidence Level 230 1,229 61 15 7.7E+07 0.5 7.6E+07 0.5 99% Confidence Level 307 1,641 82 21 1.0E+08 0.7 1.0E+08 0.7 System-H IDEA effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 372 1,974 134 40 3.8E+06 4.9 4.4E+06 4.9 N/A Geometric Mean 8.4E+04 4.7 7.6E+04 4.7 Median 43 53 27 18 1.4E+05 5.1 8.0E+04 4.9 Standard Deviation 1,218 7,203 353 86 1.2E+07 1.4 1.5E+07 1.4 Minimum 11 2.0 4.2 12 420 2.6 400 2.6 Maximum 4,600 27,000 1,400 352 4.7E+07 7.7 5.6E+07 7.7 Count 14 14 15 15 14 14 14 14 95% Confidence Level 703 4,159 195 48 7.2E+06 0.8 8.6E+06 0.8 99% Confidence Level 980 5,799 271 66 1.0E+07 1.1 1.2E+07 1.1 System-L IDEA effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 296 866 60 15 4.1E+06 5.4 3.7E+06 5.3 N/A Geometric Mean 2.3E+05 5.1 1.8E+05 5.0 Median 95 300 29 6.1 6.0E+05 5.5 4.2E+05 5.4 Standard Deviation 416 1,349 78 22 6.2E+06 1.6 5.7E+06 1.7 Minimum 3.1 6.0 3.7 0.5 200 2.3 200 2.3 Maximum 1,300 4,600 250 80 1.8E+07 7.3 1.7E+07 7.2 Count 16 16 16 16 16 16 16 16 95% Confidence Level 222 719 42 11 3.3E+06 0.9 3.0E+06 0.9 99% Confidence Level 307 994 57 16 4.5E+06 1.2 4.2E+06 1.2 System-Y IDEA effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 354 458 99 20 2.2E+08 7.5 2.1E+08 7.4 N/A Geometric Mean 161 138 80 14 3.2E+07 7.4 2.8E+07 7.4 Median 210 100 93 15 3.0E+07 7.5 4.0E+07 7.6 Standard Deviation 525 1,082 61 18 4.2E+08 1.1 4.2E+08 1.1 Minimum 16 21 7.9 2.6 2.7E+05 5.4 2.1E+05 5.3 Maximum 2,100 4,300 280 76 1.6E+09 9.2 1.6E+09 9.2 Count 15 15 15 15 15 15 15 15 95% Confidence Level 291 599 34 10 2.3E+08 0.6 2.3E+08 0.6 99% Confidence Level 404 831 47 14 3.2E+08 0.8 3.2E+08 0.9 La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-42 Innovative System Performance (9) Innovative Trench Designs, Wert and Associates, Inc. The innovative trench designs, produced by Wert and Associates, Inc., embodied an attempt to replicate denitrification processed established in non-proprietary designs installed elsewhere in the state and nation. The trench designs are broken into two groups, Design A and Design B, and each group is replicated on three sites. Design A incorporates an AX-20 system in Mode 1 to pretreat the effluent prior to discharge to the trenches. The AX-20 recirculation rates were modified to provide nitrification while also discharging higher BOD5 levels than is typical of these systems. The pump chamber discharges to one of three trenches: standard trench (gravel and perforated pipe), a lined gravel trench, and a trench containing a tube filled with shredded wood fiber nested within a larger tube. The standard trench provided a control against which to compare the performance of the other two trenches. The lined gravel trench design (anoxic trench) intended to use the BOD5 carried over from the AX-20 system to provide a carbon source to promote denitrification as the effluent became anoxic at the bottom of the liner. The tube within a tube design (wood tube trench) provided an added carbon source in the form of the wood shavings to promote denitrification. The general schematic of the system is provided in Figure 6-49. Each trench was outfitted with either a lysimeter or sampling port in order to monitor their performance. Sampling points: y Septic tank effluent (STE) y Anaerobic trench effluent (ATE) y Wood tube denitrifier effluent (WTE) y Standard Trench Lysimeter (STD-E) y Monitoring well down gradient of disposal field (MW drain) Septic tank AdvantexTM Filter AX-20 Pump tank From House Standard trench w/ lysimeter Flow meters (3) Drainfield dosing and recirculation to filter via flow splitter valve1 MWDistributing valve Anoxic trench Wood tube trench Figure 6-49. Innovative trench design A schematic. The performance data over time of the anoxic trenches is presented in Figures 6-50 through 6-52. Each chart provides the performance data in comparison with the project’s performance standard and the TN concentrations discharged from the AX-20 unit discharging to the trenches. Each unit demonstrates a parallel between the TN concentrations discharged from the AX-20 units and the anoxic trench effluent. Similarly, the performance data over time for the wood tube trenches and the standard trenches are shown in Figures 6-53 through 6-59. In each case, it appears that the AX-20 treatment process dominates the overall effluent quality for the trenches. The anoxic trenches appear to achieve a small amount of denitrification during the second half of the sampling period as compared to the standard trenches’ effluent. The wood tube trenches do not demonstrate clear denitrification; the data suggests the BOD5 is slightly higher in the effluent from these trenches than that from the standard or anoxic trenches, however, it is not clear that this is significantly different from the effluent quality leaving the AX-20 overall. When the data is plotted on the performance chart (Figure 6-59) it appears that the dissolved oxygen (DO) level is related to denitrification in that the lowest concentrations of TN in the effluent correspond to the lowest concentrations of DO in the trench effluent. It is unclear from this data whether the DO is affected more by AX-20 performance or effluent retention time in the trench. And, it must be noted that the BOD5 levels also increase during the periods of greatest nitrogen reduction. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-43 The phosphorus data provided in Tables 6-12 through 15 indicate that the reductions are not large, even in the standard trench. Apparently the rock used to bed the drainfield pipes, and which is typical of the rock used in onsite systems throughout the region, does not provide significant adsorption capacity for phosphorus reduction. Figure 6-50. System-B innovative trench design A (anoxic trench effluent). System-K innovative trench design A (anoxic trench) 0 10 20 30 40 50 60 70 80 8/6/200210/6/200212/6/20022/6/20034/6/20036/6/20038/6/200310/6/200312/6/20032/6/20044/6/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-51. System-K innovative trench design A (anoxic trench effluent). La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-44 Innovative System Performance System-P innovative trench design A (anoxic trench) 0 10 20 30 40 50 60 11/20/20021/20/20033/20/20035/20/20037/20/20039/20/200311/20/20031/20/20043/20/20045/20/20047/20/20049/20/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-52. System-P innovative trench design A (anoxic trench effluent). System-B innovative trench design A (wood tube) 0 10 20 30 40 50 60 70 9/4/200211/4/20021/4/20033/4/20035/4/20037/4/20039/4/200311/4/20031/4/20043/4/20045/4/20047/4/20049/4/200411/4/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-53. System-B innovative trench design A (wood tube trench effluent). La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-45 System-K innovative trench design A (wood tube) 0 10 20 30 40 50 60 70 80 8/6/200210/6/200212/6/20022/6/20034/6/20036/6/20038/6/200310/6/200312/6/20032/6/20044/6/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-54. System-K innovative trench design A (wood tube trench effluent). System-P innovative trench design A (wood tube) 0 20 40 60 80 100 120 10/30/200212/30/20022/28/20034/30/20036/30/20038/30/200310/30/200312/30/20032/29/20044/30/20046/30/20048/30/200410/30/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-55. System-P innovative trench design A (wood tube trench effluent). La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-46 Innovative System Performance System-B innovative trench design A (standard) 0 10 20 30 40 50 60 70 9/30/200211/30/20021/30/20033/30/20035/30/20037/30/20039/30/200311/30/20031/30/20043/30/20045/30/20047/30/20049/30/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-56. System-B standard (control) trench effluent. System-K innovative trench design A (standard) 0 10 20 30 40 50 60 70 80 8/6/0210/6/0212/6/022/6/034/6/036/6/038/6/0310/6/0312/6/032/6/044/6/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-57. System-K standard (control) trench effluent. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-47 System-P innovative trench design A (standard) 0 10 20 30 40 50 60 70 80 1/8/033/8/035/8/037/8/039/8/0311/8/031/8/043/8/045/8/047/8/049/8/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-58. System-P standard (control) trench effluent. System-P innovative trench design A (wood tube) 0 10 20 30 40 50 60 70 80 10/30/200212/30/20022/28/20034/30/20036/30/20038/30/200310/30/200312/30/20032/29/20044/30/20046/30/20048/30/200410/30/2004mg/L0 0.5 1 1.5 2 2.5 3 3.5 Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) AX-20 TN (mg/L) BOD5 (mg/L) Performance Std Dissolved Oxygen (mg/L) Figure 6-59. Example of dissolved oxygen in wood tube trench effluent. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-48 Innovative System Performance Table 6-12. Innovative trench design A standard trench effluent performance statistics. All System Standard Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 2.5 8.2 40 43 4.9 362 1.2 253 1.2 7.1 Geometric Mean 16 0.9 15 0.9 Median 1.3 4.0 41 42 4.6 14 1.1 10 1.0 6.9 Standard Deviation 4.0 12 17 20 4.3 1.7E+03 0.9 1.2E+03 0.8 1.7 Minimum ND ND 3.4 2.6 0.1 ND 0.3 ND 0.3 4.3 Maximum 24 72 68 86 15 1.1E+04 4.0 8.0E+03 3.9 11 Count 45 45 46 46 46 45 45 45 45 46 95% Confidence Level 1.2 3.6 5.1 6.1 1.3 506 0.3 362 0.3 0.5 99% Confidence Level 1.6 4.8 6.9 8.1 1.7 676 0.3 484 0.3 0.7 System-K Standard Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 2.5 4.1 53 52 7.4 1.0E+03 1.7 7.2E+02 1.6 7.2 Geometric Mean 48 1.3 39 1.2 Median 1.1 4.0 58 54 7.3 32 1.5 26 1.4 7.3 Standard Deviation 6.0 2.5 12 12 5.0 2.9E+03 1.2 2.1E+03 1.1 2.1 Minimum ND 1.0 32 27 0.2 ND 0.3 ND 0.3 4.3 Maximum 24 9.0 68 70 15 1.1E+04 4.0 8.0E+03 3.9 11 Count 15 15 16 16 16 15 15 15 15 16 95% Confidence Level 3.3 1.4 6.4 6.3 2.7 1.6E+03 0.6 1.1E+03 0.6 1.1 99% Confidence Level 4.6 1.9 8.9 8.8 3.7 2.2E+03 0.9 1.6E+03 0.9 1.5 System-B Standard Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 0.8 3.8 37 46 1.4 15 0.9 12 0.8 7.1 Geometric Mean 9 0.8 7 0.7 Median 0.5 3.0 38 42 0.5 11 1.0 8 0.9 6.9 Standard Deviation 0.4 2.8 17 25 2.3 16 0.5 15 0.4 1.5 Minimum ND ND 12 9.0 0.1 ND 0.3 ND 0.3 4.9 Maximum 1.6 11 65 86 7.2 60 1.8 54 1.7 10 Count 16 16 16 16 16 16 16 16 16 16 95% Confidence Level 0.2 1.5 9.0 13 1.2 9 0.2 8 0.2 0.8 99% Confidence Level 0.3 2.1 12 19 1.7 12 0.3 11 0.3 1.1 System-P Standard Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 4.5 18 28 30 6.0 32 1.0 35 1.1 7.0 Geometric Mean 10 0.8 12 0.9 Median 3.5 12 29 29 6.7 8 0.8 12 1.1 7.1 Standard Deviation 2.9 18 13 15 2.4 54 0.7 60 0.7 1.7 Minimum 2.0 2.0 3.4 2.6 2.2 ND 0.3 ND 0.3 4.4 Maximum 12 72 45 53 8.9 200 2.3 220 2.3 9.5 Count 14 14 14 14 14 14 14 14 14 14 95% Confidence Level 1.7 10 7.8 8.9 1.4 31 0.4 34 0.4 1.0 99% Confidence Level 2.3 14 11 12 1.9 43 0.6 48 0.5 1.4 ND = non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-49 Table 6-13. Innovative trench design A (wood tube) performance statistics. All Sys Wood Tube Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 11 13 38 41 11 1.3E+03 1.5 1.2E+03 1.5 1.8 Geometric Mean 34 N/A 28 N/A Median 6.6 4.0 39 43 11 44 1.6 36 1.6 1.5 Standard Deviation 14 58 19 20 4.0 8.2E+03 1.1 7.2E+03 1.1 1.0 Minimum ND ND 1.4 1.2 5.5 ND 0.0 ND 0.0 0.5 Maximum 76 450 68 77 20 6.5E+04 4.8 5.7E+04 4.8 4.9 Count 63 63 63 48 63 63 63 63 63 62 95% Confidence Level 3.5 15 4.8 5.9 1.0 2.1E+03 0.3 1.8E+03 0.3 0.3 99% Confidence Level 4.7 19 6.4 7.9 1.3 2.7E+03 0.4 2.4E+03 0.4 0.3 Sys-K Wood Tube Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 9.2 23 52 51 16 3.0E+03 1.4 2.7E+03 1.4 2.0 Geometric Mean 32 1.0 33 N/A Median 4.1 2.5 56 55 15 34 1.5 29 1.4 1.5 Standard Deviation 16 95 15 15 2.5 1.4E+04 1.2 1.2E+04 1.1 1.4 Minimum ND ND 19 19 10 ND 0.0 ND 0.0 0.5 Maximum 76 450 68 68 20 6.5E+04 4.8 5.7E+04 4.8 4.9 Count 22 22 22 16 22 22 22 22 22 22 95% Confidence Level 7.2 42 6.5 7.8 1.1 6.1E+03 0.5 5.4E+03 0.5 0.6 99% Confidence Level 9.8 58 8.8 11 1.5 8.4E+03 0.7 7.3E+03 0.7 0.8 Sys-B Wood Tube Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 7.2 5.1 34 43 9.1 5.1E+02 1.7 4.8E+02 1.6 1.6 Geometric Mean 44 N/A 31 N/A Median 4.8 4.0 37 41 8.5 40 1.6 24 1.4 1.6 Standard Deviation 6.8 2.5 20 25 2.1 1.1E+03 1.1 1.1E+03 1.2 0.7 Minimum 1.2 2.0 1.4 1.2 6.1 ND 0.0 ND 0.0 0.8 Maximum 31 11 60 77 12 4.4E+03 3.6 4.2E+03 3.6 3.2 Count 19 19 19 16 19 19 19 19 19 19 95% Confidence Level 3.3 1.2 9.6 13 1.0 5.4E+02 0.5 5.2E+02 0.6 0.3 99% Confidence Level 4.5 1.6 13 18 1.4 7.4E+02 0.7 7.1E+02 0.8 0.5 Sys-P Wood Tube Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) Mean 16 8.7 27 30 9.1 2.6E+02 1.5 2.3E+02 1.4 1.8 Geometric Mean 28 1.2 22 1.0 Median 11 4.0 25 25 8.6 64 1.8 53 1.7 1.5 Standard Deviation 15 23 13 16 2.7 6.6E+02 0.9 5.7E+02 1.0 0.7 Minimum 2.8 ND 9.1 8.4 5.5 ND 0.3 ND 0.3 0.5 Maximum 70 110 45 57 16 2.3E+03 3.4 2.3E+03 3.4 3.1 Count 22 22 22 16 22 22 22 22 22 21 95% Confidence Level 6.7 10 5.9 8.3 1.2 2.9E+02 0.4 2.5E+02 0.4 0.3 99% Confidence Level 9.2 14 8.1 11 1.6 4.0E+02 0.6 3.4E+02 0.6 0.4 ND = non detect, N/A = statistic not calculable La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-50 Innovative System Performance Table 6-14. Innovative trench design A (anoxic trench) performance statistics. All Systems anoxic trench effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) GPD Mean 6.8 3.2 34 39 10 1.4E+03 2.0 1.0E+03 2.0 1.4 116 Geometric Mean 87 1.7 72 1.6 Median 5.4 2.0 32 37 9.3 130 2.1 110 2.0 1.3 106 Standard Deviation 7.4 4.8 19 22 4.3 6.8E+03 0.9 4.9E+03 0.9 0.6 21 Minimum ND ND 1.3 3.9 2.4 ND 0.3 ND 0.3 0.5 103 Maximum 40 34 69 76 18 5.0E+04 4.7 3.7E+04 4.6 3.8 140 Count 57 57 57 48 57 57 57 57 57 57 3 95% Confidence Level 2.0 1.3 5.0 6.3 1.1 1.8E+03 0.2 1.3E+03 0.2 0.2 51 99% Confidence Level 2.6 1.7 6.7 8.4 1.5 2.4E+03 0.3 1.7E+03 0.3 0.2 118 Sys-K Anoxic Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) GPD Mean 10 4.3 49 52 15 2.7E+03 2.2 2.1E+03 2.1 1.6 106 Geometric Mean 142 2.0 128 1.9 Median 8.2 2.0 52 59 14 140 2.1 110 2.0 1.5 107 Standard Deviation 11 7.2 16 16 1.7 1.1E+04 0.8 8.2E+03 0.9 0.8 18 Minimum 1.7 0.5 22 21 12 8 0.9 6 0.8 0.7 79 Maximum 40 34 69 68 18 5.0E+04 4.7 3.7E+04 4.6 3.8 141 Count 20 20 20 16 20 20 20 20 20 20 16 95% Confidence Level 5.0 3.4 7.3 8.3 0.8 5.2E+03 0.4 3.8E+03 0.4 0.4 9.6 99% Confidence Level 6.8 4.6 10 12 1.1 7.1E+03 0.5 5.3E+03 0.6 0.5 13 Sys-B Anoxic Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) GPD Mean 3.7 2.7 27 36 7.7 1.1E+03 2.4 578 2.3 1.1 140 Geometric Mean 202 2.2 152 2.1 Median 3.2 2.0 25 35 7.2 251 2.4 231 2.4 1.0 136 Standard Deviation 2.9 3.3 19 26 2.6 3.1E+03 0.7 1.4E+03 0.7 0.5 40 Minimum ND ND 1.3 3.9 2.5 8 0.9 6 0.8 0.5 81 Maximum 12 14 55 76 11 1.4E+04 4.1 6.4E+03 3.8 2.3 275 Count 20 20 20 17 20 20 20 20 20 20 17 95% Confidence Level 1.4 1.5 8.7 13 1.2 1.4E+03 0.3 647 0.3 0.2 21 99% Confidence Level 1.8 2.1 12 18 1.7 2.0E+03 0.5 885 0.4 0.3 29 Sys-P Anoxic Trench Effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosph. (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli Dissolved Oxygen (mg/L) GPD Mean 6.5 2.4 23 28 6.6 206 1.5 247 1.4 1.5 103 Geometric Mean 23 1.2 19 1.1 Median 6.5 2.0 25 24 7.2 28 1.4 20 1.3 1.4 94 Standard Deviation 4.4 2.0 10 14 2.0 507 0.8 641 0.8 0.5 35 Minimum 1.2 ND 7.0 6.9 2.4 ND 0.3 ND 0.3 0.5 54 Maximum 15 8.0 36 49 10 1.6E+03 3.2 2.0E+03 3.3 2.6 202 Count 17 17 17 15 17 17 17 17 17 17 16 95% Confidence Level 2.3 1.0 5.2 7.9 1.0 260 0.4 330 0.4 0.2 19 99% Confidence Level 3.1 1.4 7.1 11 1.4 359 0.6 454 0.6 0.3 26 ND = non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-51 Table 6-15. AX-20 performance statistics in design A. System-K AX-20 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. coli Mean 8.0 5.0 53 15 5.1E+03 2.2 3.2E+04 2.3 Geometric Mean 5.8 3.6 51 15 165 2.0 203 2.0 Median 7.5 5.0 54 15 110 2.0 100 2.0 Standard Deviation 5.8 3.3 12 3.0 1.8E+04 1.1 1.1E+05 1.3 Minimum ND ND 30 7.3 10 1.0 4 0.6 Maximum 24 13 69 20 7.2E+04 4.9 4.2E+05 5.6 Count 16 16 16 16 16 16 16 16 95% Confidence Level 3.1 1.8 6.6 1.6 9.5E+03 0.6 5.6E+04 0.7 99% Confidence Level 4.3 2.4 9.1 2.2 1.3E+04 0.8 7.8E+04 1.0 System-B AX-20 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. coli Mean 7.8 8.5 37 9.1 1.1E+03 2.2 820 2.1 Geometric Mean 6.8 7.5 33 8.9 165 1.9 134 N/A Median 7.6 8.0 38 8.2 100 2.0 100 2.0 Standard Deviation 4.2 4.3 16 2.1 2.6E+03 1.0 1.5E+03 1.0 Minimum 2.3 3.0 11 6.4 ND 0.3 ND 0.0 Maximum 17 17 59 12 1.1E+04 4.0 6.0E+03 3.8 Count 17 17 17 17 17 17 17 17 95% Confidence Level 2.1 2.2 8.5 1.1 1.4E+03 0.5 770 0.5 99% Confidence Level 2.9 3.0 12 1.5 1.9E+03 0.7 1.1E+03 0.7 System-P AX-20 effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. Coli Log E. coli Mean 12 5.6 32 10 126 1.5 104 1.4 Geometric Mean 10 5.2 30 9.3 31 1.3 26 1.2 Median 11 5.0 30 8.9 19 1.3 22 1.3 Standard Deviation 7.2 2.5 11 3.0 239 0.7 210 0.7 Minimum 2.7 3.0 14 5.8 ND 0.3 ND 0.3 Maximum 22 12 51 17 880 2.9 820 2.9 Count 16 16 16 16 16 16 16 16 95% Confidence Level 3.9 1.3 5.9 1.6 128 0.4 112 0.4 99% Confidence Level 5.3 1.8 8.1 2.2 176 0.5 154 0.5 ND = non detect Innovative trench design B used a soil bed for the nitrification process during the first portion of the field test. The soil bed received effluent via a drip distribution system. This soil bed then drained through gravel to an underlying lined gravel filled trench that included two wood tubes for an added carbon source. (Figure 6-60) The lined trench was designed to become the anoxic environment to facilitate denitrification. The soil filter for System-J was replaced with a sand filter early in the field test period. The soil filters were also replaced at the end of the sampling period for System-P and System-M. These repairs were performed due to either hydraulic or organic overload to the soil filter or errors in installation or design that caused premature failure. The performance data over time is provided in Figures 6-61 through 6-63. These systems demonstrate good nitrification capabilities during the first portion of the sampling period (Systems-P and –J) and some possible denitrification (System-M). After this point, the nitrification processes for both Systems-M and –P begin to decline La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-52 Innovative System Performance and TN, BOD5 and TSS concentrations increase. The soil filters for these systems were not replaced until the summer of 2004 and the sampling events for these systems halted while they were in obvious failure; therefore there is only one sample point following this repair. The performance charts indicate the gap in data by dashed lines on the effluent quality parameters. The trends implied by the dashed lines cannot be verified by the data existing for these systems. Figure 6-60. Innovative trench design B schematic. 0 10 20 30 40 50 60 70 80 9/3/200211/3/20021/3/20033/3/20035/3/20037/3/20039/3/200311/3/20031/3/20043/3/20045/3/20047/3/20049/3/200411/3/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std Figure 6-61. System-J innovative trench design B effluent. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-53 0 20 40 60 80 100 120 140 8/27/200210/27/200212/27/20022/27/20034/27/20036/27/20038/27/200310/27/200312/27/20032/27/20044/27/20046/27/20048/27/200410/27/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std The dashed line at the end of the sampling record indicates a long interval between samples. Any potential trend indicated by the lines is unverifiable by existing data. Figure 6-62. System-M innovative trench design B effluent. 0 10 20 30 40 50 60 70 8/27/200210/27/200212/27/20022/27/20034/27/20036/27/20038/27/200310/27/200312/27/20032/27/20044/27/20046/27/20048/27/200410/27/2004mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) TSS (mg/L) BOD5 (mg/L) Performance Std The dashed line at the end of the sampling record indicates a long interval between samples. Any potential trend indicated by the lines is unverifiable with existing data. Figure 6-63. System-P innovative trench design B effluent. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-54 Innovative System Performance Table 6-16. Innovative trench design B performance statistics. All System Innovative Trench Design-B effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 21 13 26 27 1.8 5.6E+04 2.8 4.3E+04 2.7 170 Geometric Mean 6.8E+02 2.2 4.8E+02 2.1 Median 5.8 6.0 21 19 1.1 3.8E+02 2.6 3.0E+02 2.5 125 Standard Deviation 32 18 18 24 2.1 2.2E+05 1.6 1.8E+05 1.5 79 Minimum ND ND 3.4 0.0 0.2 ND 0.3 ND 0.3 124 Maximum 140 88 77 123 9.7 1.4E+06 6.1 1.2E+06 6.1 261 Count 43 43 44 45 45 43 43 43 43 3 95% Confidence Level 10 5.6 5.6 7.1 0.6 6.7E+04 0.5 5.7E+04 0.5 196 99% Confidence Level 13 7.5 7.5 9.5 0.8 9.0E+04 0.7 7.6E+04 0.6 452 System-J Innovative Trench Design-B effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 5.9 4.3 34 34 2.1 2.7E+04 2.6 1.6E+04 2.4 261 Geometric Mean 3.6E+02 1.8 2.3E+02 1.7 Median 3.6 3.0 39 18 1.7 2.0E+02 2.3 2.0E+02 2.3 243 Standard Deviation 4.9 4.0 20 33 1.8 7.0E+04 1.6 4.7E+04 1.5 96 Minimum ND ND 7.2 0.0 0.4 ND 0.3 ND 0.3 95 Maximum 16 13 73 123 6.4 2.6E+05 5.4 1.8E+05 5.3 482 Count 15 15 14 15 15 15 15 15 15 15 95% Confidence Level 2.7 2.2 12 18 1.0 3.9E+04 0.9 2.6E+04 0.9 53 99% Confidence Level 3.8 3.1 16 25 1.4 5.4E+04 1.3 3.6E+04 1.2 74 System-M Innovative Trench Design-B effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 41 22 26 28 2.4 1.3E+04 2.9 1.3E+04 2.9 124 Geometric Mean 7.9E+02 2.6 7.4E+02 2.6 Median 28 12 22 19 1.6 6.6E+02 2.8 5.9E+02 2.8 97 Standard Deviation 43 25 21 22 2.9 2.3E+04 1.2 2.4E+04 1.3 59 Minimum 1.2 1.0 4.0 5.7 0.2 10 1.0 14 1.1 84 Maximum 140 88 77 68 9.7 6.4E+04 4.8 7.2E+04 4.9 300 Count 15 15 15 15 15 14 14 14 14 14 95% Confidence Level 24 14 12 12 1.6 1.3E+04 0.7 1.4E+04 0.7 34 99% Confidence Level 33 19 16 17 2.2 1.9E+04 1.0 2.0E+04 1.0 47 System-P Innovative Trench Design-B effluent BOD5 (mg/L) TSS (mg/L) TN (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 16 13 18 20 0.8 1.3E+05 3.0 1.0E+05 2.8 125 Geometric Mean 1.1E+03 2.2 6.3E+02 2.0 Median 4.1 6.0 19 20 0.6 1.3E+03 3.1 1.1E+03 3.0 122 Standard Deviation 22 14 9.2 11 0.7 3.7E+05 1.9 3.2E+05 1.8 34 Minimum ND ND 3.4 4.3 0.2 ND 0.3 ND 0.3 69 Maximum 72 36 36 45 2.5 1.4E+06 6.1 1.2E+06 6.1 202 Count 13 13 15 15 15 14 14 14 14 15 95% Confidence Level 13 8.5 5.1 6.0 0.4 2.1E+05 1.1 1.8E+05 1.1 19 99% Confidence Level 19 12 7.1 8.3 0.5 3.0E+05 1.5 2.6E+05 1.5 26 ND = non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-55 Figure 6-64. Nayadic unit cross-section. (10) Nayadic, Consolidated Treatment Systems, Inc. The Nayadic unit is designed with nested chambers: an inner reactor vessel, where the forced aeration process occurs, and an outer clarification chamber, where the suspended growth matter settles from the effluent. The overall shape of the unit derives from the Imhoff cone. (Figure 6-64) While operating, primary clarifier effluent is discharged to the inner reactor where compressed air is pumped into the bottom of the chamber and allowed to rise in a pipe, creating a Venturi effect. The outer chamber is a quiescent area where solids can settle out of suspension and fall towards the bottom of the cone. The white ring shown in Figure 6-64 is a scum baffle to keep floating material from leaving the unit. Figure 6-65 provides a basic schematic of the La Pine Project installations and a more detailed description of the process is available on the web site for Consolidated Treatment Systems, Inc. at: http://www.consolidatedtreatment.com/nayadic.asp. Figures 6-66 through 6-68 provide the performance data over time for the three systems installed for the La Pine Project. The first year of operation was often characterized by high BOD5 and TSS values, which may have been due to system maturation confounded by air compressor or recirculation pump malfunctions. The high spike in TN with an accompanying decline in nitrification in March 2003 in Figure 6-68 corresponds to a time when the recirculation pump failed and the control panel for the pump needed to be re-programmed; it is unclear if the compressor experienced problems at the same time as the recirculation pump but compressor problems might be implied by the decline in nitrification. Performance of this system improved for the balance of the sampling period with some excursions in BOD5 quality. The other two systems have experienced multiple air compressor related problems with a corresponding impact on effluent quality. Bacteria reductions in all three systems exceeded the performance standard by achieving a 2.6 to 2.8 log reduction based on individual geometric means. No phosphorus reduction was expected or recorded in these systems. Overall, (Table 6-17) the systems appear capable of producing relatively good effluent quality (for example, System-B); however, the general performance of the systems serves to highlight the need for particular attention to maintenance requirements with these systems and perhaps onsite systems in general. Communication between the vendor and the installer/maintenance provider may have been an issue in the La Pine Project in that some important maintenance activities (e.g. compressor maintenance) were overlooked during the first year to year and a half of operation (example, Figure 6-68). Conversations with the designated maintenance provider during the field test also highlighted potential conflicts that may arise when the maintenance provider is also an onsite system installer or excavator. This combination of businesses may increase the maintenance provider’s response time to service calls on malfunctioning systems if they are working against a deadline to complete an installation job. Additionally, the maintenance providers in the La Pine Project using this business model tended to be more reactive than proactive when addressing maintenance issues. However, this could also have been a result of the informal nature of the training received during the demonstration project. As a result of observing this type of business model, the project team recommends a strong educational component included in any maintenance provider certification program with the certification program also allowing homeowner, vendor and regulator feedback to the quality of work of the maintenance provider. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-56 Innovative System Performance Figure 6-65. Nayadic system schematic. System-B Nayadic effluent over time 0 20 40 60 80 100 11/5/011/5/023/5/025/5/027/5/029/5/0211/5/021/5/033/5/035/5/037/5/039/5/0311/5/031/5/043/5/045/5/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-66. System-B Nayadic effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-57 System-D Nayadic effluent over time 0 20 40 60 80 100 120 140 160 11/5/011/5/023/5/025/5/027/5/029/5/0211/5/021/5/033/5/035/5/037/5/039/5/0311/5/031/5/043/5/045/5/047/5/049/5/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-67. System-D Nayadic effluent over time. System-M Nayadic effluent over time 0 20 40 60 80 100 120 140 160 11/5/011/5/023/5/025/5/027/5/029/5/0211/5/021/5/033/5/035/5/037/5/039/5/0311/5/031/5/043/5/045/5/047/5/049/5/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-68. System-M Nayadic effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-58 Innovative System Performance Table 6-17. Nayadic performance statistics. All systems' Nayadic effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 42 17 37 12 1.2E+05 2.7 1.1E+05 2.6 121 Geometric Mean 680 2.4 550 2.3 Median 36 11 35 11 380 2.6 400 2.6 101 Standard Deviation 34 17 17 4.5 6.6E+05 1.4 6.1E+05 1.5 48 Minimum 1.6 ND 5.9 5.0 ND 0.3 ND 0.3 86 Maximum 150 96 101 24 4.6E+06 6.7 4.2E+06 6.6 176 Count 78 80 80 79 80 80 80 80 3 95% Confidence Level 7.7 3.8 3.8 1.0 1.5E+05 0.3 1.4E+05 0.3 119 99% Confidence Level 10 5.0 5.1 1.3 2.0E+05 0.4 1.8E+05 0.4 275 System-D Nayadic effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 48 14 38 12 1.1E+04 2.8 9.8E+03 2.7 101 Geometric Mean 930 2.6 780 2.5 Median 40 13 40 12 640 2.8 420 2.6 99 Standard Deviation 29 10 12 1.7 2.1E+04 1.4 1.8E+04 1.4 15 Minimum 14 2.0 18 10 4 0.6 ND 0.3 75 Maximum 110 44 65 15 6.4E+04 4.8 5.8E+04 4.8 140 Count 25 26 26 25 26 26 26 26 22 95% Confidence Level 12 4.0 4.9 0.7 8.5E+03 0.6 7.2E+03 0.6 7 99% Confidence Level 16 5.4 6.6 0.9 1.1E+04 0.8 9.8E+03 0.8 9 System-M Nayadic effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 56 30 36 7.5 3.5E+05 3.0 3.3E+05 3.0 176 Geometric Mean 1.4E+03 2.4 1.3E+03 2.4 Median 40 25 27 7.4 1400 3.1 1350 3.1 134 Standard Deviation 42 22 22 1.4 1.1E+06 1.9 1.1E+06 1.9 114 Minimum 1.6 6.0 5.9 5.0 ND 0.3 ND 0.3 5.9 Maximum 150 96 101 10 4.6E+06 6.7 4.2E+06 6.6 361 Count 26 26 26 26 26 26 26 26 23 95% Confidence Level 17 8.9 8.8 0.6 4.6E+05 0.8 4.3E+05 0.8 49 99% Confidence Level 23 12 12 0.8 6.2E+05 1.0 5.8E+05 1.0 67 System-B Nayadic effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 23 8.1 38 16 1.7E+03 2.3 1.4E+03 2.2 86 Geometric Mean 240 2.2 170 2.0 Median 19 6.0 45 16 185 2.3 130 2.1 90 Standard Deviation 19 5.4 17 4.6 5.7E+03 0.8 4.9E+03 0.9 16 Minimum 2.1 ND 8.9 10 8 0.9 10 1.0 38 Maximum 68 22 63 24 3.0E+04 4.5 2.6E+04 4.4 112 Count 27 28 28 28 28 28 28 28 19 95% Confidence Level 7.6 2.1 6.7 1.8 2.2E+03 0.3 1.9E+03 0.3 7 99% Confidence Level 10 2.8 9.1 2.4 3.0E+03 0.4 2.6E+03 0.5 10 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-59 (11) NiteLess, On Site Wastewater Management, LLC The NiteLess wastewater treatment system (On Site Wastewater Management, LLC, Cherry Hill, NJ)is contained entirely within a single tank that was manufactured in Oregon to the designer’s specifications. The designer installed the treatment components on site. The system incorporates a suspended growth forced aeration process for the nitrification portion of the treatment train. The effluent then enters a divided settling chamber where a powdered carbon source mixed with bacteria is added in an anoxic environment to promote denitrification. The effluent then enters a pump chamber before discharge to the soil absorption unit. (Figure 6-69) Figure 6-69. NiteLess system schematic. The performance data over time provided in Figures 6-70 through 6-72 indicate that the nitrification portion of the process never fully established itself within any of the three systems. In order to evaluate possible reasons why the process was not working, the project team first reviewed the alkalinity available to support the nitrification process. Table 6-18 indicates that, on average, sufficient alkalinity is present in the effluent to allow most of the NH4 in the effluent to be nitrified. Secondly, a review of the homeowner surveys does not reveal any significant sources of toxins from chemicals or prescription medications used in the households. Thirdly, the dissolved oxygen (DO) levels recorded in the pump chamber that discharges to the soil absorption field average 0.9 mg/L on average in the three systems, which is lower than the DO levels in the primary clarifier (average = 1.2 mg/L). A low DO content in the final clarifier is not necessarily unexpected because of the anoxic environment created in the secondary settling process; however, the DO results coupled with high TN and the absence of NO3 indicate there were other issues with the treatment process. The short periods around October 2002 shown on the performance charts are times when the aeration process was running 24 hours a day. At that point, the nitrification appears to increase and the TKN and NH4 levels decline. However, the field notes observe that the vendor returned the aeration process to cycling on and off during the day shortly thereafter and the effluent was not nitrified for the duration of the sampling period. Based on these observations and the data, it appears that the nitrification process was limited by the quality of the aeration unit serving the system, either due to inadequate aeration time during the process day or due to the effectiveness of the air delivery mechanism. Each system also produced high spikes of BOD5 that are shown in Figures 6-70, 6-73, and 6-74. For example, the spike on Figure 6-73 (BOD5 = 600 mg/L) is significantly higher than the BOD5 contained in the primary clarifier effluent sample taken the same day (370 mg/L) and it is higher than the BOD5 level discharged from the primary La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-60 Innovative System Performance clarifier on average for the previous four months (average BOD5 = 230 mg/L). These spikes may be a result of difficulties controlling the amount of the carbon/bacteria powdered mixture added to the effluent because of caking from the moisture present in the system. TSS reductions achieved by this system are comparable to a two-compartment septic tank or somewhat better (Table 6-19). Because of the tank design, it is not possible to determine whether the TSS reduction achieved is due to the treatment process or the meandering flow path through the multiple chambers in the processing tank. Bacteria removal in these systems was low, 0.6 log reduction, for the three systems based on the geometric mean. Based on the effluent quality from these systems over all the monitored parameters (Table 6-19), these systems did not meet the field test performance criteria. Table 6-18. Alkalinity requirements for the NiteLess systems. Alkalinity requirements for nitrification (mg/L) Sys-P Total Alkalinity available Sys-P Alk needed Sys-L Total Alkalinity available Sys-L Alk needed Sys-T Total Alkalinity available Sys-T Alk needed All sys Total Alkalinity available All Sys Alk needed Mean 320 352 319 280 327 340 323 324 Median 338 414 306 300 300 321 325 321 Standard Deviation 102 163 61 105 72 76 78 120 Minimum 85 45 238 121 150 164 85 45 Maximum 488 621 415 478 493 478 493 621 Count 19 19 20 20 23 23 62 62 95% Confidence Level 49 79 29 49 31 33 20 30 99% Confidence Level 68 108 39 67 43 45 26 40 System-T NiteLess effluent over time 0 20 40 60 80 100 120 140 12/17/012/17/024/17/026/17/028/17/0210/17/0212/17/022/17/034/17/036/17/038/17/0310/17/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std TSS (mg/L) BOD5 (mg/L) Figure 6-70. System-T NiteLess effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-61 System-P NiteLess Effluent Nitrogen Species over time 0 10 20 30 40 50 60 70 80 90 100 2/20/024/20/026/20/028/20/0210/20/0212/20/022/20/034/20/036/20/038/20/0310/20/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-71. System-P NiteLess effluent nitrogen species over time. System-L NiteLess Effluent Nitrogen Species over time 0 10 20 30 40 50 60 70 80 90 1/8/023/8/025/8/027/8/029/8/0211/8/021/8/033/8/035/8/037/8/039/8/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std Figure 6-72. System-L NiteLess effluent nitrogen species over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-62 Innovative System Performance System-P NiteLess Effluent BOD/TSS over time 0 100 200 300 400 500 600 2/20/024/20/026/20/028/20/0210/20/0212/20/022/20/034/20/036/20/038/20/0310/20/03mg/LBOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-73. System-P NiteLess effluent BOD5/TSS over time. System-L NiteLess Effluent BOD/TSS over time 0 100 200 300 400 500 600 700 1/8/023/8/025/8/027/8/029/8/0211/8/021/8/033/8/035/8/037/8/039/8/03mg/LBOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-74. System-L NiteLess effluent BOD5/TSS over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-63 Table 6-19. NiteLess performance statistics. All System NiteLess effluent (NTE) (no apparent maturation period) BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 122 46 61 10 4.1E+05 4.7 3.6E+05 4.6 108 Geometric Mean 4.6E+04 4.5 3.8E+04 4.4 Median 74 41 61 9.8 7.4E+04 4.9 5.9E+04 4.8 106 Standard Deviation 126 28 18 3.0 1.1E+06 1.1 1.1E+06 1.1 27 Minimum 26 8.0 27 4.8 10 1 10 1 63 Maximum 680 180 120 20 7.4E+06 6.9 7.6E+06 6.9 192 Count 61 62 62 62 62 62 62 62 51 95% Confidence Level 32 7.0 4.6 0.8 2.8E+05 0.3 2.7E+05 0.3 8 99% Confidence Level 43 9.4 6.1 1.0 3.8E+05 0.4 3.6E+05 0.4 10 System-P NTE (no apparent maturation period) BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 175 64 67 12 2.1E+05 4.1 1.8E+05 4.1 84 Geometric Mean 1.3E+04 3.8 1.2E+04 3.7 Median 91 60 74 11 1.7E+04 4.2 1.4E+04 4.1 82.5 Standard Deviation 152 33 21 3.4 5.3E+05 1.4 4.3E+05 1.4 16 Minimum 34 25 35 8.2 10 1 10 1 63 Maximum 600 180 100 20 2.3E+06 6.4 1.8E+06 6.3 114 Count 18 19 19 19 19 19 19 19 16 95% Confidence Level 76 15.9 10.0 1.6 2.6E+05 0.7 2.1E+05 0.7 8 99% Confidence Level 104 21.8 13.7 2.2 3.5E+05 0.9 2.8E+05 0.9 11 System-L NTE (no apparent maturation period) BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 139 45 53 7.6 3.7E+05 5.0 3.1E+05 4.9 114 Geometric Mean 1.1E+05 5.0 7.6E+04 4.8 Median 86 38 57 7.1 1.0E+05 5.0 8.3E+04 4.9 109 Standard Deviation 148 26 15 2.0 8.3E+05 0.7 5.9E+05 0.8 28 Minimum 30 9.0 27 4.8 8200 3.9 3800 3.6 74 Maximum 680 110 80 12 3.7E+06 6.6 2.5E+06 6.4 192 Count 20 20 20 20 20 20 20 20 17 95% Confidence Level 69 12 6.9 1.0 3.9E+05 0.3 2.8E+05 0.4 14 99% Confidence Level 94 16.6 9.4 1.3 5.3E+05 0.4 3.8E+05 0.5 20 System-T NTE (no apparent maturation period) BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 66 32 63 11 6.0E+05 4.8 5.7E+05 4.8 122 Geometric Mean 7.0E+04 4.7 6.4E+04 4.7 Median 69 34 61 10 7.2E+04 4.9 6.6E+04 4.8 125 Standard Deviation 26 13 16 1.7 1.6E+06 1.0 1.6E+06 1.0 21 Minimum 26 8.0 47 7.8 1400 3.1 1600 3.2 89 Maximum 130 51 120 13 7.4E+06 6.9 7.6E+06 6.9 157 Count 23 23 23 23 23 23 23 23 18 95% Confidence Level 11 5.7 7.0 0.7 6.9E+05 0.4 7.0E+05 0.4 10 99% Confidence Level 15 7.8 9.5 1.0 9.4E+05 0.6 9.6E+05 0.6 14 La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-64 Innovative System Performance (12) NITREX™ filter, University of Waterloo / Lombardo Associates, Inc. The NITREX filter contains a “proprietary patented nitrate-reactive media” to convert nitrate to nitrogen gas (denitrification). The NITREX media is contained in a prefabricated tank for the typical residential installation. As installed for the La Pine Project (Figure 6-75), the tanks are open to the surface and covered by wood chip mulch. Nitrate-rich wastewater flows by gravity from the lined sand filter that precedes the NITREX unit and which provides the nitrification step required prior to discharge to the NITREX. The project team decided to install the NITREX filter in this configuration in order to avoid pairing proprietary devices in a field test situation. (Figure 6-76) This system represents one of few systems in the La Pine Project that are designed to denitrify wastewater by using a supplemental carbon source rather than recirculating the effluent to the septic tank. More information on this product is available on the web at: http://www.lombardoassociates.com/nitrex.shtml. Figures 6-77 through 6-80 show the performance data of two NITREX systems over time. These charts represent about three years of monthly or bimonthly sampling data. Figures 6-77 and 6-78 provide the nitrogen species over time. The initial spike in the nitrogen species in both systems shows the effluent has been well nitrified by the sand filter. Note that the spike is not high compared to the sand filter effluent quality (mean = 51 mg/L, Table 5-9) and the nitrogen levels decline signficantly in the first six months of the sampling period. The data presented in these charts is not corrected for dilution; however, they provide the relative concentrations of the nitrogen species. The vertical exaggeration present in the charts creates the illusion that the effluent is not well nitrified because TKN comprises most of the remaining TN. However, when the values of the concentrations are considered, the effluent quality is significantly better than the performance standard. The vertical red line in Figure 6-77 indicates a point at which the homeowner stated that she had started using every flush toilet bowl cleaners. The homeowner left the tablets in the toilet tanks until they dissolved, which appeared to disrupt the performance of the NITREX filter as shown. The tablet dissolved in January 2004, which is after the end of the sampling period. The NITREX filter, while apparently disrupted somewhat by the action of the toilet tablets, still performed better than the La Pine Project TN performance standard of 10 mg/L. A review of the performance of the sand filter preceding this unit shows that the toilet tablets did not significantly disrupt the nitrification process. (Figure 6-81) This result may indicate the relative sensitivity of the nitrifying vs. denitrifying bacteria to toxins in the effluent and points to a potential research need, particularly for the use of onsite systems in areas with nitrogen sensitive receiving environments. Figures 6-79 and 6-80 show the BOD5 and TSS data for the same systems. There is a large spike in the BOD5 levels in the effluent that declines in the first year of the sampling period. Reviewing the performance of the sand filter (Table 5-9) preceding the NITREX unit, it is apparent that the increase in BOD5 is a function of the NITREX filter maturation process. A significant amount of hydrogen sulfide was released in the pump chamber following the NITREX unit and this subsided significantly along with the BOD5 levels during the first year of operation. The sampling team observed no odors (when the pump chamber was closed) or liquid at the surface of the NITREX unit during this maturation period. The charts of the performance data over time are not adjusted for any dilution effects from precipitation or irrigation whereas the nitrogen statistics provided in Table 6-20 are adjusted for dilution. Overall, the two systems performed well in relation to the La Pine Project performance standard. The BOD5 average is high but that statistic includes a portion of the initial spike; the nitrogen species (particularly the nitrification of the effluent) defined the maturation period of the innovative systems rather than BOD5 or TSS removal because of the overall project emphasis on nitrogen reduction. Figure 6-75. NITREX filter during installation. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-65 The bacteria present in the NITREX filter effluent are very low in number and represent at least a 5-log reduction from septic tank effluent. However, it is important to note that the sand filters preceding the units achieve a significant bacteria reduction before the effluent enters the NITREX filter. Therefore, while the NITREX filter demonstrates an additional level of bacteria reduction, it is not possible to quantify the full reduction achievable by the unit from the data produced by this study. Similarly, the phosphorus reduction capacity of the NITREX filters is not clear from the performance statistics in Table 6-20 because the lined sand filters preceding these units remove between 60 and 65% of the phosphorus in the effluent before it enters the NITREX filter. However, significant phosphorus reduction would not be expected by these units because of the lack of apparent adsorption sites in the media. Figure 6-76. NITREX system schematic. System-S NITREX Effluent Nitrogen Species over time 0 2 4 6 8 10 12 14 16 18 12/26/002/26/014/26/016/26/018/26/0110/26/0112/26/012/26/024/26/026/26/028/26/0210/26/0212/26/022/26/034/26/036/26/038/26/0310/26/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std The data in this chart has not been corrected for dilution. The chart illustrates the relative levels between the different nitrogen species. Owner began using an every flush toilet bowl cleaner tablet. The toilet tablet dissolved in January 2004. Figure 6-77. System-S NITREX effluent nitrogen species over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-66 Innovative System Performance System-F NITREX Effluent Nitrogen Species 0 5 10 15 20 25 30 35 40 12/26/002/26/014/26/016/26/018/26/0110/26/0112/26/012/26/024/26/026/26/028/26/0210/26/0212/26/022/26/034/26/036/26/038/26/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) Performance Std The data in this chart has not been corrected for dilution. The chart illustrates the relative levels between the different nitrogen species. Figure 6-78. System-F NITREX effluent nitrogen species over time. System-S NITREX Effluent BOD/TSS over time 0 20 40 60 80 100 120 140 160 180 200 12/26/002/26/014/26/016/26/018/26/0110/26/0112/26/012/26/024/26/026/26/028/26/0210/26/0212/26/022/26/034/26/036/26/038/26/0310/26/03mg/LBOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-79. System-S NITREX effluent BOD5 and TSS performance over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-67 System-F NITREX Effluent BOD/TSS over time 0 50 100 150 200 250 12/26/002/26/014/26/016/26/018/26/0110/26/0112/26/012/26/024/26/026/26/028/26/0210/26/0212/26/022/26/034/26/036/26/038/26/03mg/LBOD5 (mg/L) TSS (mg/L) Performance Standard Figure 6-80. System-F NITREX effluent BOD5/TSS over time. System-S Lined Sand Filter Performance 0 10 20 30 40 50 60 70 12/26/002/26/014/26/016/26/018/26/0110/26/0112/26/012/26/024/26/026/26/028/26/0210/26/0212/26/022/26/034/26/036/26/038/26/0310/26/03mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) Performance Std Figure 6-81. System-S lined sand filter effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-68 Innovative System Performance Table 6-20. NITREX system performance statistics. Two Systems NFE after maturation BOD5 (mg/L) TSS (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 18 3.9 2.4 4.0 5 0.5 6 0.4 148 Geometric Mean 3 0.4 3 0.4 Median 10 3.0 1.7 4.2 ND 0.3 ND 0.3 149 Standard Deviation 17 3.1 2.0 1.9 8 0.4 14 0.4 47 Minimum 2.5 ND ND 0.9 ND 0.3 ND 0.3 36 Maximum 66 15 8.5 7.9 44 1.6 82 1.9 243 Count 29 48 37 48 46 46 46 46 48 95% Confidence Level 6.5 0.9 0.7 0.5 2 0.1 4 0.1 14 99% Confidence Level 8.7 1.2 0.9 0.7 3 0.1 6 0.2 18 System-F NFE after maturation BOD5 (mg/L) TSS (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 24 4.3 1.8 4.3 7 0.5 9 0.5 125 Geometric Mean 3 0.4 3 0.4 Median 17 3.0 1.6 4.4 ND 0.3 ND 0.3 132 Standard Deviation 20 3.6 0.9 2.0 10 0.4 19 0.5 37 Minimum 5.7 ND 0.8 0.9 ND 0.3 ND 0.3 36 Maximum 66 15 3.9 7.9 44 1.6 82 1.9 189 Count 14 24 19 24 23 23 23 23 24 95% Confidence Level 11 1.5 0.4 0.9 4 0.2 8 0.2 16 99% Confidence Level 16 2.0 0.6 1.2 6 0.3 11 0.3 21 System-S NFE after maturation BOD5 (mg/L) TSS (mg/L) TN w/o dilution Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 8.0 3.5 3.0 3.6 3 0.4 3 0.4 170 Geometric Mean 3 0.4 ND 0.3 Median 6.6 3.0 1.7 3.4 ND 0.3 ND 0.3 173 Standard Deviation 4.9 2.6 2.6 1.7 4 0.3 3 0.2 45 Minimum 2.5 1.0 0.5 1.0 ND 0.3 ND 0.3 67 Maximum 21 12 8.5 6.4 22 1.3 16 1.2 243 Count 13 24 18 24 23 23 23 23 24 95% Confidence Level 3.0 1.1 1.3 0.7 2 0.1 1 0.1 19 99% Confidence Level 4.2 1.5 1.7 1.0 3 0.2 2 0.1 26 ND = Non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-69 (13) Puraflo®, Bord na Móna, Inc. Bord na Móna, Inc. (http://www.bnm-us.com/puraflo.html) produces the Puraflo® system (Figure 6-82), a packed bed filter using Irish peat fiber as the filter media. The systems installed for the La Pine Project used 6 modules with the flow from three of the modules returned to the beginning of the septic tank to promote denitrification; the other three modules dispersed treated effluent to the basal soil. The vendor installed the modules on a gravel pad to distribute the effluent from their bases. The system schematic is provided in Figure 6-83 and the wastewater sampling locations for the system included pump tank effluent and peat filter effluent. The performance data over time is presented in Figures 6-84 through 6-86. The three systems installed for the field test performed comparably to each other and met the project’s performance criteria for BOD5, TSS and bacteria reduction; in terms of reduction levels, the three systems’ performance compared favorably to sand filter performance (Tables 5-4, 5-8 and 5-9) for these parameters and exceeded the project’s standards. The TN levels discharged by the systems (Table 6-21) also appear comparable to the single-pass sand filters in the project. Because the actual septic tank effluent quality cannot be determined at these sites due to recirculation to the primary clarifier, the performance of these systems can be compared to the data from the single-pass septic tank population in the La Pine Project. Using this comparison, the Puraflo units appear to achieve the same level of denitrification as sand filters. However, the data implies that the actual denitrification rate is much higher. Each Puraflo system achieves near perfect nitrification of the wastewater (TN = 51 mg/L, NO3 = 48 mg/L, TKN = 3 mg/L) and the pump tank effluent samples contain no NO3 (TN = 57 mg/L, NO3 = 0.02 mg/L, TKN = 57 mg/L), which indicates that all NO3 returned to the primary clarifier is denitrified. Because 50% of the flow is returned to the primary clarifier, it should follow that close to 50% of the TN discharged from the residence is removed from the effluent. The actual effectiveness of the denitrification process may be obscured by dilution from the incoming household wastewater and, possibly, high incoming household waste strengths. A simplistic estimate of influent waste strength can be calculated by doubling the effluent TN concentrations, which produces 96, 86 and 130 mg/L TN for System-M, -F, and –S respectively. (This is not an accurate representation of waste strength because the return flow is governed by timer while the system receives whatever flow the house is discharging. Therefore the return flow will be a varying percentage of the total.) The average influent TN concentration using this approach would be 102 mg/L, which is somewhat high but still within the range of average concentrations discharged by single-pass septic tanks in the La Pine Project. Thirty-five percent of the La Pine septic tanks discharged TN concentrations more than 70 mg/L on average and with values ranging to a maximum of 233 mg/L. It is somewhat unusual to have all three households with one type of system all have high waste strength but not impossible. Two of these households have children that were prescribed antibiotics, one household used liquid fabric softeners, all the households used antibacterial cleaning products, and one household used every flush toilet bowl deodorizers. Each house used some of these products and so no control was available to determine if the chemically or biologically active substances affected the waste strength of the households and/or the performance of these systems. The system, as installed for the La Pine Project, is designed to promote denitrification by returning 50% of the forward flow to the inlet pipe of the septic tank. The amount of forward flow returned to the primary clarifier in these installations cannot be changed because the rate is controlled by the design of the peat modules rather than by a splitter basin or other flow splitting device that would allow modification of the recirculation rate based on treatment needs. Typical recirculation rates for recirculating gravel or sand filters range between 3:1 to 5:1 with the majority of the flow returned through the treatment system. (Crites and Tchobanoblous, 1998) The 1:1 recirculation rate set in these Puraflo systems is significantly lower than these typical rates. A study of these systems under varying recirculation ratios could help clarify the denitrifying capability of the product. Figure 6-82. Puraflo module. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-70 Innovative System Performance 1 Figure 6-83. Puraflo system schematic. System-F Puraflo effluent over time 0 10 20 30 40 50 60 12/10/012/10/024/10/026/10/028/10/0210/10/0212/10/022/10/034/10/036/10/038/10/0310/10/0312/10/032/10/044/10/046/10/048/10/0410/10/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-84. System-F Puraflo effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-71 System-M Puraflo effluent over time 0 10 20 30 40 50 60 70 80 12/10/012/10/024/10/026/10/028/10/0210/10/0212/10/022/10/034/10/036/10/038/10/0310/10/0312/10/032/10/044/10/046/10/048/10/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-85. System-M Puraflo effluent over time. System-S Puraflo effluent over time 0 20 40 60 80 100 120 140 160 180 200 4/2/026/2/028/2/0210/2/0212/2/022/2/034/2/036/2/038/2/0310/2/0312/2/032/2/044/2/046/2/048/2/0410/2/0412/2/04mg/LNH4 As N (mg/L) Nitrate-Nitrite As N (mg/L) TKN (mg/L) TN (mg/L) BOD5 (mg/L) TSS (mg/L) Performance Std Figure 6-86. System-S Puraflo effluent over time. La Pine National Decentralized Wastewater Treatment Demonstration Project Page 6-72 Innovative System Performance Table 6-21. Puraflo effluent performance statistics. All Systems' Puraflo Effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 2.6 3.6 51 12 7.1E+03 2.4 4.8E+03 2.2 171 Geometric Mean 267 2.1 205 2.0 Median 1.9 3.0 52 9.5 195 2.3 120 2.1 162 Standard Deviation 2.6 3.7 14 6.1 3.2E+04 1.1 2.0E+04 1.0 56 Minimum ND ND 28 5.1 ND 0.3 ND 0.3 93 Maximum 16 18 91 25 2.3E+05 5.4 1.4E+05 5.1 366 Count 54 54 53 54 54 54 54 54 62 95% Confidence Level 0.7 1.0 3.9 1.7 8.8E+03 0.3 5.6E+03 0.3 14 99% Confidence Level 0.9 1.3 5.2 2.2 1.2E+04 0.4 7.4E+03 0.4 19 System-M Puraflo Effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 1.7 2.8 48 9.1 688 1.8 597 1.7 140 Geometric Mean 49 1.4 49 1.5 Median 1.6 3.0 47 8.4 40 1.6 42 1.6 116 Standard Deviation 1.0 2.0 12 2.5 2.1E+03 0.9 1.9E+03 0.9 47 Minimum ND ND 28 6.1 ND 0.3 ND 0.3 97 Maximum 3.9 8.0 72 16 8.6E+03 3.9 7.8E+03 3.9 241 Count 17 17 17 17 17 17 17 17 20 95% Confidence Level 0.5 1.0 6.1 1.3 1.1E+03 0.5 9.7E+02 0.4 22 99% Confidence Level 0.7 1.4 8.4 1.8 1.5E+03 0.7 1.3E+03 0.6 30 System-F Puraflo Effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 2.8 4.2 43 8.2 1.4E+04 2.7 8.8E+03 2.5 207 Geometric Mean 597 2.6 336 2.2 Median 2.2 3.0 43 8.8 340 2.5 210 2.3 217 Standard Deviation 2.0 4.7 9.1 1.6 5.0E+04 1.0 3.1E+04 1.1 63 Minimum ND ND 29 5.1 16 1.2 ND 0.3 93 Maximum 7.7 18 57 10 2.3E+05 5.4 1.4E+05 5.1 366 Count 21 21 20 21 21 21 21 21 22 95% Confidence Level 0.9 2.1 4.3 0.7 2.3E+04 0.5 1.4E+04 0.5 28 99% Confidence Level 1.2 2.9 5.8 1.0 3.1E+04 0.6 1.9E+04 0.7 38 System-S Puraflo Effluent after maturation BOD5 (mg/L) TSS (mg/L) TN (mg/L) Total Phosphorus (mg/L) Fecal Coliform Log Fecal E. coli Log E. coli GPD Mean 3.3 3.5 65 21 5.0E+03 2.5 4.1E+03 2.4 164 Geometric Mean 655 2.4 529 2.4 Median 1.9 2.0 63 21 345 2.5 130 2.1 159 Standard Deviation 3.9 3.6 11 2.0 1.5E+04 1.0 1.3E+04 1.0 30 Minimum ND ND 51 18 10 1.0 10 1.0 117 Maximum 16 16 91 25 6.0E+04 4.8 5.2E+04 4.7 225 Count 16 16 16 16 16 16 16 16 20 95% Confidence Level 2.1 1.9 6.0 1.1 8.0E+03 0.6 6.9E+03 0.5 14 99% Confidence Level 2.9 2.7 8.3 1.5 1.1E+04 0.8 9.5E+03 0.7 19 ND = non detect La Pine National Decentralized Wastewater Treatment Demonstration Project Innovative System Performance Page 6-73 Conclusions The La Pine National Demonstration Project produced a large amount of information on the field performance of innovative onsite wastewater treatment systems. While the primary goal of the study was to identify the best denitrifying technologies and designs, useful information was also collected on the performance of septic tanks, conventional systems, and those innovative systems that may be useful for situations where there may be treatment needs other than denitrification (ex. BOD5/TSS or bacteria reduction). The findings of the field test highlight the need for a formal, well-organized approach to developing the maintenance provider profession. The La Pine Project required the vendors of the innovative systems to select and train their designated maintenance providers which resulted in an uneven level of training from one product to the next. The baseline level of training (ex. basic information on the biochemistry of wastewater treatment processes) was missing in most cases, which created difficulties and additional instances of miscommunication when vendors were troubleshooting system performance from a distance. The lack of defined maintenance schedules and reporting requirements also served to undercut the effectiveness of this type of maintenance program. A main recommendation of the project is to promote the development of the maintenance provider profession so that individual providers can focus on onsite system maintenance as a primary business. The combination of the excavator/installer business with providing onsite system maintenance did not work well in this demonstration project because these individuals tended to respond first to the needs of the excavation/installation business and secondly to maintenance requirements. The maintenance provider profession can be promoted by enlarging the pool of systems participating or required to participate in the maintenance program. Sand filter and pressure distribution systems are as technologically complex as most innovative treatment systems (i.e. both types of systems are controlled by comparable control panels, floats, pumps and effluent distribution systems) and therefore require comparable maintenance for the long term. The EPA voluntary maintenance guidelines assume that all decentralized systems are included in maintenance programs. Another recommendation of this project is to develop long-term data on the performance of onsite systems. Most studies, including this demonstration, are short lived and do not provide extended examination of systems that are expected to operate for twenty years or more. Informal observations of effluent quality from the La Pine Project systems after the field test ended indicate that the performance of these systems has changed. Without continued organized monitoring and evaluation, it is not possible to determine whether these changes are detrimental or beneficial to the environmental protection goals of the region. And, if decentralized systems are expected to be permanent solutions to wastewater treatment needs, then long-term attention to the quality of their performance is warranted. Alternative or innovative wastewater treatment systems can provide comparable or improved performance over conventional systems, particular where such systems are designed and installed to promote denitrification. Recent information generated by studies of trace constituents in wastewater, including personal care products and pharmaceuticals, indicates that decentralized wastewater treatment systems can provide high levels of treatment for traditionally measured wastewater constituents. However, the emerging focus on trace constituents in wastewater is highlighting the need to maintain sufficient separation in the soil between wastewater discharges and water tables (Hinkle, 2005; George Tchobanaglous, personal communication) because the soil provides additional adsorption and treatment capacity to attenuate these trace constituents. References Burks, B.D. and M.M. Minnis. 1994. Onsite Wastewater Treatment Systems. Hogwarth House, Limited, Madison, WI. Crites, R., and G. Tchobanoglous. 1998. Small and Decentralized Wastewater Management Systems. McGraw- Hill, Boston, MA. Hinkle, S.R., R.J. Weick, J.M. Johnson, J.D. Cahill, S.G. Smith, B.J. Rich. 2005. Organic Wastewater Compounds, Pharmaceuticals, and Coliphage in Ground Water Receiving Discharge from Onsite Wastewater Treatment Systems near La Pine, Oregon: Occurrence and Implications for Transport. US Geological Survey Scientific Investigations Report 2005-5055, 98 p.