1 Evaluation of OSS Nitrogen Removal Technologies Regulatory Round Table Review Series March 11, 2014 Lynn Schneider, Washington Department of Health Office of Shellfish and Water Protection

2 $EPA Nutrient NEP Grant Study Partners

3 A.Source diversion B.Post-septic tank treatment C.Design of the soil dispersal component (drainfield) Wastewater Nitrogen Management Approaches A B C

4 Problems:  N reduction in OSS is highly variable  Limited treatment options  Regional environmental and water source affects on N removal not well-known OSS Nitrogen Removal Project Design Nitrogen In Nitrogen Out Biological System Changes Nitrogen from soluble to gaseous

5 Objectives:  Maximize N removal efficiencies  Verify performance objective (<20 mg/L TN full test avg.)  Expand reliable, affordable options OSS Nitrogen Removal Project Design

6 Methods: Partner with UW & Ecology to: Use ETV Nutrient Reduction Protocol Develop standards & guidance OSS Nitrogen Removal Project Design

7 ETV-Nutrient Reduction Protocol Minimum of 12 consecutive months Daily Design loading 480 gpd (100% + 10% of the rated capacity) 6 AM – 9 AM: ~35% of flow 11 AM – 2 PM: ~25% of flow 5 PM – 8 PM: ~40% of flow Stress Testing (effect of home activities) washday loading working parent low-loading power/equipment failure one week vacation

8 ETV-Nutrient Reduction Protocol Sampling Days: Minimum of 12 monthly samples + additional 38 stress day sampling Total 55 data days

9 ETV-Nutrient Reduction Protocol Performance Parameters: Total N, NH 3 -N, NOx-N (NO 3 +NO 2 ), Total P, CBOD, COD, TSS/VSS, alkalinity Site Grab for lab: fecal coliform In-situ samples: dissolved oxygen, pH, temperature

10 Meters & Probes

11 Snoqualmie WWTP Test Site

12 Snoqualmie WWTP Test Site w/autosampler locations

13 O2O2 O2O2 Organic N NH 4 + NO 2 - NO 3 - N 2 Ammonification Nitrification Denitrification (Aerobic) (Anoxic) Two step process: 1) Nitrification - nitrifies NH 4 + to NO 3 - 2) Denitrification - reduces NO 3 - to nitrogen gas Nitrogen Biochemical Transformations Organic N N2N2 Biological System ALKALI O2O2 C C C

14 Nitrification is a two step process: 1.Utilizing bicarbonate alkalinity, Nitrosomonas bacteria will oxidize ammonia to nitrite by NH O 2 + HCO 3 - C 5 H 7 O 2 N + NO H 2 O + H 2 CO 3 2.Then Nitrobacter bacteria will oxidize nitrite to nitrate mole for mole by NO2 - + NH H 2 CO 3 + HCO O 2 + C 5 H 7 O 2 N + H 2 O + NO 3 Nitrogen Biochemical Transformations

15 Denitrification is a one step process - Note: We used two variations: 1.NO 3 + Woodchips N 2 + OH - + CO 2 + H 2 O 2.NO 3 + BOD from septic tank influent N 2 + OH - + CO 2 + H 2 O Nitrogen Biochemical Transformations

16 Vegetated Recirculating Gravel Filter (VRGF) 1 8 Nitrification Denitrification

17 VRGF August 2012 June 2013

18 VRGF Influent and Effluent Nitrogen Over 12-Month Test Period

19 VRGF Influent and Effluent Fecal Coliform Over 12-Month Test Period

20 Parameter unitsInfluentEffluent Total Nmg/L48.6 (9.5)15.1 (1.9) NH 3 -Nmg/L29.3 (5.3)4.1 (1.0) NOx-Nmg/L-9.5 (2.1) Org-Nmg/L-1.6 (0.9) BOD/CBOD*mg/L314 (98)5.6 (1.8) TSSmg/L354 (137)3.2 (2.0) VSSmg/L324 (131)2.9 (1.7) COD/SCOD*mg/L715 (223)21.0 (7.2) Total Phosphorusmg/L5.8 (1.3)3.5 (1.1) Fecal Coliform** CFU/100 mL 8.4E+62.3E+5 Alkalinity as CaCO 3 mg/L231 (36)153 (23) pH 7.4 (0.3)6.8 (0.2) Average Performance for VRGF Over 12-Month Test (68.9% TN Removal) *Effluents, **Geometric mean, ( ) is standard deviation

21 VRGF Clogging Problem

22 Enhanced Recirculating Gravel Filter (ERGF) 1 8 (5) Nitrification Denitrification

23 ERGF July 2012 January 2013

24 Parameter unitsInfluentEffluent Total Nmg/L48.6 (9.5)8.6 (2.2) NH 3 -Nmg/L29.3 (5.3)6.8 (1.9) NOx-Nmg/L-0.6 (0.6) Org-Nmg/L-1.3 (0.5) BOD/CBOD*mg/L314 (98)8.6 (1.9) TSSmg/L354 (137)5.3 (2.2) VSSmg/L324 (131)4.4 (2.0) COD/SCOD*mg/L715 (223)24.6 (5.7) Total Phosphorusmg/L5.8 (1.3)3.5 (1.4) Fecal Coliform**CFU/100 mL8.4E+64.6E+5 Alkalinity as CaCO 3 mg/L231 (36)203 (27) pH 7.4 (0.3)6.9 (0.2) Average Performance for ERGF Over 12-Month Test (82.3% TN Removal) *Effluents, **Geometric mean, ( ) is standard deviation

25 ERGF Influent and Effluent Nitrogen Over 12-Month Test Period

26 ERGF Influent and Effluent Fecal Coliform Over 12-Month Test Period

27 Recirculating Gravel Filter (RGF) & Woodchip Bed - Two Stage System Nitrification Denitrification days

28 RGF & Woodchip Bed August 2012 June 2013

29 RGF & Woodchip Bed July 2012 June 2013

30 Parameter unitsInfluentRGF Effluent Average Woodchip Effluent Total Nmg/L48.6 (9.5) 23.9 (5.4)4.0 (3.8) NH 3 -Nmg/L29.3 (5.3) 0.7 (0.4)0.5 (0.5) NOx-Nmg/L- 21 (5.5)2.4 (3.7) Org-Nmg/L- 2.2 (1.2)1.1 (0.3) BOD/CBOD*mg/L314 (97.8) 4.7 (2.6)10.8 (14.1) TSSmg/L354 (137) 10.1 (12.7)2.1 (2.0) VSSmg/L324 (131) 5.8 (5.5)0.9 (2.3) COD/SCOD*mg/L715 (223) 21.6 (5.5)37.6 (20.7) Total Phosphorus mg/L5.8 (1.3) -3.4 (1.9) Fecal Coliform** CFU/100 mL 8.4E+6 1.6E E+03 Alkalinity as CaCO 3 mg/L231 (36) 84 (28)154 (36.6) pH 7.4 (0.3) 6.8 (0.3)6.6 (0.2) Average Performance for RGF-Woodchip Bed Over 12-Month Test Period *Effluents, **Geometric mean, ( ) is standard deviation (91.8% TN Removal and 960 CFU/100 mL effluent fecal coliform)

31 Nitrogen Removal in RGF and Woodchip Bed Over 12-Month Test Period

32 Fecal Coliform Removal in RGF and Woodchip Bed Over 12-Month Test Period

33 CBOD in RGF and Woodchip Bed Effluents Over 12-Month Test Period

34 ParameterUnit Vegetated RGF Enhanced RGF RGF/ Woodchip Bed Total Areaft Treatment Media Depthft RGF 2.8-Woodchip Bed Average Effluent TNmg/L15.1 (18.5)8.6 (12.3)4.0 (13.1) Average TN removal% Average Effluent CBODmg/L5.6 (8.2)8.6 (11.22)10.8 (28.9) Geometric mean of Effluent Fecal Coliform CFU/100 mL230,000460, Comparison of the 3 Nitrogen Removal Systems ( ) is 95% Percentile

35 1.Webpage posting the ETV Reports summarizing the results from the 3 systems 2.Provide technical support for Hood Canal On-Site Sewage System Nitrogen Reduction (HCOSSNR) demonstration project 3.Complete RS&Gs for the RGF/Woodchip Bed and the VRGF systems Project Outcomes

36 UW Civil and Environmental Engineering David Stensel - UWCEE Project Coordinator Michael Brett – UWCEE Project QA Manager Crystal Grinnell – Research Assistant Stephany Wei - Research Assistant Songlin Wang – UWCEE field engineer City of Snoqualmie Wastewater Treatment Plant Tom Holmes - Wastewater Superintendent Lyle Beach - Laboratory Analyst Brian Richardson - Senior Operator Peter Lombardi, Orenco Systems Inc. Dennis Hallahan, Infiltrator Systems Inc. Acknowledgements from Health

37 To learn more about the project go to search for Denitrification Lynn Schneider (360) Washington State Department of Health Office of Shellfish and Water Protection

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