Town of North Castle, NY Sewer District No. 2 WWTP

Transcription

1 Town of North Castle, NY Sewer District No. 2 WWTP Robert Butterworth, PE, BCEE Project Principal Jan Salzman, PE, BCEE Project Manager March 9, 2016

2 Presentation Overview Purpose and Scope of Study Background Existing Conditions WWTP Limits and Capacity Recommendations Project Cost Estimates Age and Condition Related Improvements Staffing

3 Purpose and Scope Purpose of Study assist the Town in planning for the future while protecting the environment Scope of Study - Evaluate two alternatives Increase Capacity to 0.60 mgd Increase Capacity to 0.70 mgd

4 Historical Background 1983 Construction and commissioning (0.38 mgd) EPA develops LIS nitrogen requirements Nitrogen limits added to WWTP permit 2005 WWTP improvement projects begin 2009 Sewer Capacity Task Force Study 2010 WWTP improvement completed, NYSDEC modifies permit to 0.45 mgd 2012 NYSDEC modifies permit to 0.50 mgd 2013 Sewer Capacity Study Update 2015 Pilot Test: Activated Carbon 2016 Capacity Increase Study 0.60/0.70 mgd

5 Existing Conditions Flows and Loading Parameter Influent Flow Rate Average annual Maximum month (design flow) Peak day Peak hour Recent Influent Data (September 2013-August 2015) mgd mgd mgd 0.82 mgd CBOD Average daily Maximum month TSS Average daily Maximum month Ammonia Average daily Maximum month 860 lbs/day 1200 lbs/day 860 lbs/day 1,300 lbs/day 70 lbs/day 95 lbs/day

6 Existing Conditions WWTP Performance at Current Flows Excellent! Parameter Permit Limit Recent Effluent Data Total Suspended Solids 10.0 mg/l 2.1 mg/l CBOD 5.0 mg/l 2.2 mg/l Total Nitrogen 13 lbs/day 7.5 lbs/day Ammonia 1.18/2.20 mg/l 0.2 mg/l

7 Total Nitrogen (TN) Limit Special requirement for NC SD2 WWTP due to Long Island Sound Aggregate limit for Zone 7: Westchester County and the Town of North Castle 13 pounds per day Limit - calculated on 12-month rolling average DEC will not allow increase in TN limit To increase flow without increasing pounds per day, need to decrease concentration (mg/l) Need to improve nitrogen removal

8 Process Flow Schematic (Existing) INFLUENT PUMPS GRINDER EQT PST RBC FST PUMP STATION DENITE FILTER UV DIS- INFECTION POST AERATION OUTFALL CLOTH FILTER 20% Methanol RDT SLUDGE HOLDING

9 Process Flow Schematic (New) INFLUENT PUMPS GRINDER EQT PST RBC FST PUMP STATION DENITE FILTER UV DIS- INFECTION POST AERATION OUTFALL CARBON FILTER 20% Methanol RDT SLUDGE HOLDING

10 WWTP Capacity Needs WWTP Capacity (MGD) Existing Permit Limit IBM Reserve IBM Reserve IBM Reserve IBM Reserve Recent Maximum Month Flow 2013 Capacity Study Maximum Month Flow 0.60 mgd Maximum Month Flow 0.70 mgd Maximum Month Flow 0 Utilized Capacity Projected Flow Evaluated Capacity Evaluated Capacity

11 Capacity Needs by Process Max Mo (Design) Flow Influent Pumping Prelim Treatment Primary Clarification R B C Secondary Clarification Filter Pump Station Denite Filter G A C UV Disinfection Equalization Reaeration Solids Handling 0.60 mgd 0.70 mgd X X X X X X X X X X X = Improvement Needed

12 Recommendations for Capacity Related Improvements Future Maximum Month Flow of 0.60 mgd Necessary Improvements: Construct one additional primary clarifier. Construct one additional denitrifying filter cell. Construct a granular carbon adsorption system for additional nitrogen removal. Construct additional solids handling capacity Construct building and site improvements. Future Maximum Month Flow of 0.70 mgd Construct additional equalization storage volume. Construct one additional primary clarifier. Construct an additional rotating biological contactor train (RBC). Construct two additional denitrifying filter cells. Construct a granular carbon adsorption system for additional nitrogen removal. Construct additional solids handling capacity Construct building and site improvements.

13 Preliminary Opinion of Project Cost 0.60 mgd Cost Component Installed Cost (Rounded) Primary clarifier $350,000 Rotary drum thickener $530,000 Piping modifications $350,000 Plant water system $200,000 Carbon adsorption system $650,000 Additional denitrifying filter cell $500,000 Building and site improvements $500,000 Subtotal $3,100,000 Electrical allowance $650,000 Contingency $750,000 Fiscal, legal, administrative, engineering $650,000 PROJECT COST $5,200,000

14 Preliminary Opinion of Project Cost mgd Cost Component Installed Cost (Rounded) Equalization $300,000 Primary clarifier $350,000 Nitrifying RBC train $500,000 Denitrifying filter (2 new cells) $900,000 Rotary drum thickener $530,000 Piping modifications $350,000 Plant water system $200,000 Carbon adsorption (GAC) $850,000 Building and site improvements $1,000,000 Subtotal $5,000,000 Electrical allowance $1,500,000 Contingency $1,200,000 Fiscal, legal, administrative, engineering $1,200,000 PROJECT COST $9,000,000

15 Age and Condition Related Improvements Plant Water System Site Lighting Existing UV Disinfection Building Existing RBC Building* UV Disinfection System* Clarifier Scum Boxes* Odor Control Systems* Sludge Holding Tank Blowers* Administration Building* *Not included in cost estimates

16 Staffing Increased Capacity: more equipment more run time = more maintenance more sludge to process more process control measures More Labor Increased Complexity Additional Labor must be Skilled and Qualified Recommendation: Full Time, Grade 2 WW Operator

17 Next Steps Select desired WWTP capacity Meet with NYSDEC (recommended) Begin the Design Process: Work with Engineer to develop Design Documents and Engineering Report Complete Form NY2A (Permit Modification Request) Approvals Bidding Construction

18 Questions?

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