Jaffrey, New Hampshire

Transcription

1 Jaffrey, New Hampshire One community s experience Meeting the Challenges of Stringent Water Quality Based Discharge Limits NHWPCA SYMPOSIUM NPDES PERMITTING June 13, 2012: Manchester, NH Presented by: Neil P. Cheseldine, P.E. npc@wright-pierce.com Photograph by New England Aerial Photography

2 Jaffrey, New Hampshire Cheshire County Population: 5,500 WWTF 1.25 MGD design average flow 3.80 MGD design peak flow 40% of population served Significant Industries Millipore 120,000 GPD D.D. Bean 5,000 GPD

3 Jaffrey, New Hampshire Small New England Town Straddles Contoocook River Headwaters of Contoocook River

4 Jaffrey, New Hampshire Mount Monadnock Region

5 Jaffrey WW History 1960 s Stabilization ponds 1960 s 1970 s Facilities planning 1970 s planning study study Aerated lagoons, UV upgrade Contoocook R. WLA NPDES new limits limits (including ammonia and metals) 1995 Administrative Order (AO)

6 Jaffrey WW History Numerous studies AO mandated mandated upgrades to other existing wastewater facilities TMDL Study Study 2009 AWWTF AWWTF completed completed 2010 Final NPDES permit 2011 Tertiary Tertiary upgrade upgrade

7 Wastewater Discharge Compliance Drivers River flows are lowest at the headwaters in Jaffrey Town decided early on to sewer central areas to allow more dense development and protect the river Aged sewer infrastructure (50+ years) results in high I/I rates Relatively high discharge design flow Above factors lead to Low Dilution Factor

8 Compliance Challenges 1992 WLA study (NHDES): Modeling predicts DO problems Stringent BOD and Ammonia limits 1994 NPDES permit also included metals (copper, lead, silver, zinc) New aerated lagoon WWTF not designed for new limits Difficult to get public support to replace lagoon facility prior to 20- year design life Focus on compliance strategies that preserved lagoon facility

9 Contoocook River

10 Road to Compliance Initial Strategies Considered ( ) Solar aquatics Lagoon Fixed Film (Lemna, Ringlace) Decentralized systems Land-based discharge RIBs Effluent storage Creative permitting trigger flows dynamic limits Regionalization - Peterborough

11 Evaluation of Initial Compliance Strategies Large scale comprehensive evaluations of strategies because: High cost of a new AWT facility ($12-15 Million) Uncertainty of other future discharge limits associated with continued discharge to river (i.e. Phosphorus, aluminum, others?) Not many similar situations to learn from NHDES supported consideration of land based discharge

12 Lagoon Treatment Upgrade Strategies Solar aquatics and fixed film ammonia treatment Relatively new and unproven technology in 1990 s Pilot scale studies conducted Processes unreliable and not compatible with cold temps Phosphorus and aluminum discharge limits not considered

13 River Discharge Elimination Strategies NPDES National Pollutant Discharge Elimination System Decentralized system for existing sewered area not feasible high I/I flows lack of suitable discharge areas Land Based Discharge: NHDES first suggested RIBs during Value Engineering workshop Recent NH success for similar sized project in North Conway

14 Land Discharge Strategy RIBs determined most suitable for design flow Site survey studies conducted to identify candidates Intense field investigations conducted on at least five sites Mapping Test pits, borings, monitoring wells Infiltrometer and load cell tests Groundwater flow modeling Study costs > $1 million

15 Land Discharge Strategy (cont d) Land discharge more difficult to predict Higher study cost Go till No Field studies escalate in magnitude, comprehension, and cost (and keep going as long as still feasible). Jaffrey sites had suitable near field soils Sites failed for variety of reasons (discovered during modeling phase) Influence on significant potential private water source Influence on Town s closed landfill Hydraulic breakout and mounding

16 Initial Compliance Strategies Summary Treatment upgrades not technically feasible Decentralized cost prohibitive Land discharge not technically feasible (insufficient capacity on available land Regionalization cost prohibitive, same water quality issues Flow control and permit strategies Not legally possible within State water quality regs and insufficient storage volume All strategies that would preserve the existing lagoon treatment facility were determined not feasible Subsequent strategies focused on AWT facility and negotiation of discharge permit requirements

17 Water Quality Criteria Moving target Site specific limits more difficult than cookie cutter limits Contoocook River low flows in Jaffrey high value recreation sensitive downstream including impoundments (ponds) Low Dilution Factor < 2 to 1

18 TMDL Study TMDL Total Maximum Daily Load Contoocook River listed on 303(d) list due to Jaffrey NPDES noncompliance DO and chlorophyll-a water quality violations (based on previous modeling) River and WWTF data collection TMDL Preliminary Draft 2006 TMDL Final Draft 2007

19 TMDL Study (cont d) NHDES selects QUAL2E model Phosphorus impacts considered First experience using this model 2005 Town/W-P hire scientific consultant, HydroQual National and International experience with water quality modeling November 2005 Town requests AO compliance schedule extension for TMDL completion December 2005 EPA denies schedule extension and indicates technical concerns with TMDL

20 TMDL Study

21 TMDL Study

22 TMDL Study All other dissolved oxygen, phosphorous and chlorophyll a impairments are based on predicted water quality violations from modeling conducted for this study.

23 TMDL Study

24 TMDL Study 3 - Threatened means that either an effluent parameter is in significant non-compliance with the approved NPDES permit (4B-T) and/or a calibrated water quality model indicates that under full design flow and limiting conditions the NPDES permit would result in WQS exceedances (5-T).

25 TMDL Summary Cooperative effort NHDES & Town Initial TMDL draft recommends phosphorus limit 0.2 mg/l subsequently increased in response to Town (HydroQual) comments Numerous technical negotiations: sediment oxygen demand, reaeration rates, periphyton impact, biological kinetic rates, etc. Draft TMDL completed by NHDES February 2007 submitted to EPA for approval recommended P Limit 0.5 mg/l (summer) TMDL NOT approved by EPA

26 Parallel Compliance Efforts NHDES issued AOs 2004-present EPA issued AOs AO compliance schedule (AWT) required parallel effort with TMDL Town was reluctant to design and construct new AWT until TMDL completed and NPDES limits set EPA refused to link AWT schedule to future NPDES limits (i.e. Phosphorus). Suggested design for P=0.2 mg/l and add more treatment later if limit any lower

27 NPDES Permit 2007 Draft NPDES Permit issued P Limit 0.16 mg/l (based on Gold book criteria) 30 days to submit Town comments Town Team assembled: DPW Director, Town Engineer Legal: Dana Bisbee, Esq (Devine, Millimet & Branch) Engineer: Wright-Pierce Scientist: HydroQual Significant Town comments 2 years no EPA response, Compliance clock still ticking

28 NPDES Permit (cont d) September 2009 final NPDES Permit issued by EPA 30 days for appeal Town Team reconvened New state (DES) requirements summer flow reduction 1.25mdg -> 0.75 MGD future P criteria references Appeals submitted Comments limited to Draft Permit comments and new additions to permit EPA Environmental Appeals Board (EAB) NHDES Water Council 401 Cert.

29 NPDES Permit (cont d) Negotiations with DES and EPA over 9 month period Heavy dose of legal and technical discussions Key items dilution factor phosphorus mass limit summer flow limit aluminum limit EAB appeal stayed to accommodate negotiations

30 NPDES Appeal Strategy EAB appeal - Little chance of success most cases go on to Federal court Estimated legal and consultant costs of appeal were high Town selected for ARRA funding for tertiary treatment upgrade Agreements reached Town appeals withdrawn NPDES Permit modification September 2010

31 NPDES Permit Limits Summer (Jul 1 Sep 30) Non-Summer (Oct 1 Jun 30) Flow 1.25 mgd 1.25 mgd CBOD 10 mg/l 10 mg/l TSS 10 mg/l 10 mg/l NH3-N 1.0 mg/l 7.0 mg/l) (5.3 mg/l May) (1.1 mg/l Oct) TP-P 1.54 lb/d (0.15 mg/l) Apr 1 - Oct 30 Dissolved Oxygen 1.0 mg/l 7.0 mg/l 8.0 mg/l Aluminum 87 ug/l 87 ug/l Copper 5.0 ug/l 5.0 ug/l

32 AWT Implementation Design completed June 2006 Includes tertiary filtration Bids received August $15.5M Special Town Meeting FAILED ReDesign completed January 2007 Filtration and Admin Building as Bid Alternates Base Bid - $10.5M March 2007 Town Meeting EPA attends to encourage passage PASSED AWT Construction Completed April 2009

33 Jaffrey NH AWT Upgrade Process flow diagram (A 2 O process with tertiary P removal) Influent Anaerobic Zone Anoxic Zone Aeration Tanks Oxic Zone Secondary Clarifiers Metal Salt Tertiary Process Effluent Internal Nitrate Recycle Return Activated Sludge To Solids Handling WAS to Solids Handling Tertiary Treatment Lagoon facility replaced with mechanical plant to achieve low N and P limits A 2 O oxidation ditch plant followed by ballasted flocculation* Both Bio-P and chemical P removal Design Performance P<0.1ppm* Ammonia N < 0.61 mg/l TSS/BOD < 10 mg/l (lower with tertiary treatment) *ballasted flocculation system construction recently completed

34 Tertiary Treatment Selection Originally selected cloth disk filters Design P level 0.2 mg/l included as bid alternate on AWT contract not built (NPDES limits not finalized) ARRA funding obtained ($2.87M) P limit 0.16 mg/l (possibly lower in future) Switched to Actiflo Ballasted Flocculation

35 Ballasted Flocculation

36 Tertiary project Implementation March 2009 Town Meeting Vote FAILED ARRA funding not confirmed Continued uncertainty about NPDES permit limits April 2009 ARRA funding confirmed (50% grant) November 2009 Special Town Meeting Vote PASSED Construction bid in hand Complete construction April 2011

37 Financial Information Capital Costs AWT Project - $18 M (including other facility upgrades and studies) Tertiary Project - Funding $2.8M USDA, EDA, EPA Stag, SRF Grants - $7.4M State Aid Grant program (30%) terminated in 2008 Loss of $4.2M grant funding User Rate Impact - $600 + /user

38 Other Watershed Actions Peterborough AWT to replace lagoons (recently completed) Jaffrey Aluminum AO Ambient levels exceed criteria Powder Mill Pond TMDL (ongoing) Additional phosphorus loading reductions may be necessary

39 Questions & Answers