Design, Construction and Startup of the First Enhanced Nutrient Removal Plant in Maryland Funded by the Chesapeake Bay Restoration Fund Rip Copithorn, Jeff Sturdevant, Vince Maillard GHD Clients People Performance
Introduction Chesapeake Bay 2000 Agreement Maryland, Virginia, Pennsylvania, DC Reduce N and P by 20 million and 1 million lbs, resp. Follows the 1983 agreement that resulted in the BNR program Enhanced Nutrient Removal (ENR) Program ENR Program requires WWTFs to achieve annual average effluent TN of 3 mg/l and TP of 0.3 mg/l New limits achieve only 1/3 of the reduction in Agreement
Background All WWTFs in the Chesapeake Bay watershed will be subject to strict effluent nutrient loading limits: Maryland, Pennsylvania, and Virginia already have nutrient limits Delaware, New York, and West Virginia are developing similar requirements Maryland has regulations for all 66 major WWTFs USGS MD-DE-DC Water Science Center
Funding All WWTFs 0.5 mgd or greater (total of 66 plants) Required to upgrade to BNR levels first ENR eligible items are 100% fundable Statewide flush tax ($50/yr per household) Easton, MD was first plant to enter the ENR program in MD in 2003
Easton, MD
Nitrogen Removal Previous MD Goal/ Standard Approximate Limit of Technology Nitrification BNR ENR UNR 20 mg/l 10 mg/l 5 mg/l 0 mg/l Original Permit had NH 3 Removal Only Easton Goal (3 mg/l) Permit = 4.0 mg/l
Phosphorus Removal Previous MD Standard Approximate Limit of Technology 10 mg/l 1 mg/l 0.1 mg/l 0.01 mg/l Original Permit (1.2 mg/l) New Permit (0.3 mg/l)
Overview of Existing Facility Chlorine Contact Tank Laboratory Overland Flow Terraces Maintenance Building Cl 2 & SO 2 Buildings Facultative Lagoons Outfall
Existing Process Flow Diagram Secondary Lagoon Raw Influent Primary Lagoon Overland Flow Terraces (5) Recycle Pumps Cl 2 SO 2 Post Aeration Outfall
Existing Facility Capacity = 2.35 mgd Limits BOD 5 (6/1-10/31) 20 mg/l (11/1 5/31) 30 mg/l Ammonia (6/1 10/31) 5 mg/l
New Facility Average = 4.0 mgd Design (Max Month) = 5.5 mgd Peak Day = 7.8 mgd (higher flows equalized) Limits BOD 5 (4/1-9/30) 11 mg/l (10/1 3/31) 30 mg/l TSS 30 mg/l Ammonia (4/1-9/30) 2.1 mg/l (10/1 3/31) 3.7 mg/l TP 1.2 mg/l
Future Limits and Current Goals On an average annual basis TN 4.0 mg/l (goal 3.0 mg/l) TP 0.3 mg/l
Biological Process Selection Selection of EIMCO 5-Stage Bardenpho System Workshop 2 Qualitative and quantitative analysis of remaining alternatives Biolac Orbal Bardenpho Workshop 1 Biolac Orbal Bardenpho Schreiber Batch SBR ICEAS SBR 5-Stage BNR Site Visits Capital and O&M Cost Estimates
Overview of New Facility Solids Processing Building Waste Sludge Holding Tanks Effluent Filters Pump & Blower Building Secondary Clarifiers Preliminary Treatment UV Disinfection Dried Biosolids Storage Silo Operations Building 5-Stage Bardenpho Reactors
Easton WWTF Bioreactors Process includes two (2) parallel oxidation ditches followed by postanoxic and re-aeration tanks, clarifiers, and deep bed continuouslybackwashing up-flow filters
Easton WWTF Bioreactors Oxidation ditches configured as 5-stage Bardenpho process with a racetrack style central aerobic cell aerated w/ vertical shaft surface aerators
Easton WWTF Bioreactors Process cut-away showing the Bioreactors at the Easton WWTF Aerated Racetrack Zone Anaerobic and Pre-Anoxic Zones OVIVO Eimco Water Technologies (EWT) Carrousel System Surface Aerator
Easton WWTF Bioreactors SCADA control screen for the Bioreactors at the Easton WWTF
Easton WWTF Bioreactor Volume Because influent flow and load are only about 60% of the full design values, the plant operators have only operated one of the two bioreactors since the plant went on line. Treatment Stage Units in Service Volume in Service (m 3 ) (MG) Percent of Reactor Volume Anaerobic 1 681 0.18 8% Pre Anoxic 1 681 0.18 8% Oxidation Ditch 1 5,867 1.55 70% Post Anoxic 2 1 908 0.24 11% Reaeration 1 189 0.05 2% Total Volume 8,328 2.2 100% 1 The second post anoxic zone was placed into service from October 2008 to April 2009 and October 2009 to March 2010.
Selection of Bio-Solids Treatment Process Existing process required no sludge treatment or disposal New process will produce approximately 5,000 lbs dry solids per day under average conditions Outline of major decisions Class A or B Bio-Solids Treatment method to meet Class A or B Dewatering Method Storage and/or disposal of final product
New Solids Process Flow Diagram Aerated Holding Tanks Centrifuge Dryer Storage Silo Disposal Landfill Distribution or Disposal Landfill Daily Cover Landscaping Nurseries Farms General Public
Construction $26,000,000 construction cost (50% BNR, 25% ENR) Notice to proceed 12/04 Liquid Processes Operational Oxidation Ditch 10/06 (one train, limited controls) Filter 12/06 (no chemical addition until mid 1/07) Solids Processes Operational 1/07 Substantial Completion 3/07 Startup of Oxidation Ditch w/o seeding Only one train available for > 50% flow Limited controls due to sequencing of work
MLSS and Effluent NH 3 vs. Time 4000 [MLSS] (mg/l) 3500 3000 2500 2000 1500 20 15 10 Effluent [NH3](mg/l) 1000 5 500 MLSS NH3 (mg/l) 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Time (Days) 0
Effluent Nitrogen 11 10 Start Up Plant Upset 9 8 Nitrogen (mg/l) 7 6 5 Average TN 3.18 mg/l w/o Supplemental Carbon Addition Average TN 5.52 mg/l TN Goal Average TN 2.26 mg/l w/o Supplemental Carbon Addition 4 3 2 1 0 12/15/06 3/25/07 7/3/07 10/11/07 1/19/08 4/28/08 Ammonia Nitrate TN TN Goal Average TN
Easton WWTF Nitrogen Removal Performance 45.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Influent TKN, mg/l Mar-10 Apr-10 May-10 Jun-10 Effluent Nitrogen, mg/l 4.0 mg/l Effluent TN Goal Influent TKN Effluent TN Effluent NH3 Effluent NO3
Nitrate Concentrations through Process 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 May-10 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 NO3 Concentration, N mg/l Jun-10 2ndPost-Anoxic Tank Put in Service NO3 @ Pre Anox Exit NO3 @ Ox Ditch Exit NO3 @ Post Anox Exit
Effluent Phosphorus 1.8 Start Up Plant Upset 1.5 1.2 Average TP 0.66 mg/l Phosphorus (mg/l) 0.9 Average TP 0.23 mg/l Average TP 0.22 mg/l 0.6 TP Goal 0.3 0.0 12/15/06 3/25/07 7/3/07 10/11/07 1/19/08 4/28/08 Ortho P TP TP Goal Average TP
Easton WWTF Phosphorus Removal Performance 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Jan-08 Feb-08 Mar-08 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Influent Phosphporus, mg/l Apr-10 May-10 Jun-10 Effluent Phosphorus, mg/l 0.3 mg/l Effluent TP Goal Influent TP Effluent TP Effluent OP Effluent TP GOal
OP Concentrations Through Process 25.0 20.0 15.0 10.0 5.0 0.0 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Jan 08 Feb 08 Mar 08 Apr 08 May 08 Jun 08 Jul 08 Aug 08 Sep 08 Oct 08 Nov 08 Dec 08 Jan 09 Feb 09 Mar 09 Apr 09 May 09 Jun 09 Jul 09 Aug 09 Sep 09 Oct 09 Nov 09 Dec 09 Jan 10 Feb 10 Mar 10 Anaerobic & Recycle OP Concentration, OP mg/l Apr 10 May 10 Jun 10 Ox Ditch & Post Anoxic OP Concentration, OP mg/l Anearobic Eff OP in Recycle Stream OP @ Ox Ditch Exit OP @ Post Anox Exit
Ongoing Improvements
Questions? rip.copithorn@ghd.com