New Phosphorus Removal Requirement Tips the Scales: Lessons Learned on Biosolids Management and Odor Control at the Southington CT Treatment Plant.

Transcription

1 New Phosphorus Removal Requirement Tips the Scales: Lessons Learned on Biosolids Management and Odor Control at the Southington CT Treatment Plant.

2 Plant Overview Plant Operations Interim Phosphorus Permit The Odor Surprise Operators Response Fast Track Facility Planning Sludge Thickening & Odor Control Project What s Next

3 Plant Design Capacity 7.4 MGD Average Day 15.9 MGD Peak Hourly Flow Running at o 25 % of Design Load o 55 % of Design Flow Located Central CT Quinnipiac River CT Nitrogen Trading Program Phosphorus Limits o < 0.7 mg/l interim o < 0.12 mg/l long term Map courtesy of CT Department of Economic and Community Development

4 1958 Pump Station, Primarys, Trickling Filters Secondary Clarifiers, Digesters 1980 Upgrade (Nitrify/Capacity) Primarys > Sludge Thickener Secondarys > CCTs New Primarys Added Nitrification Reactors Expanded Digester 1990 UV Disinfection 2008 Denitrification Filters

5 Pump 1950 s Plant Intermediate STs Trickling Filters Nitrification Reactors Pump Denite Filters Primary STs Nitrification STs UV Dsnfctn Pump Influent Aerated Grit River

6 Belt Filter Presses Intermediate STs Primary STs Gravity Thickeners Nitrification STs Denite Filters Digester Influent Wet Well (Cosettle)

7 Belt Presses in Operations Building Permanganate Added o To Press Feed o To Filtrate (Head of Plant) Settling Tank Odors Primary - Misting System Intermediate Misting System Pump Waste Sludge at Night Tickling Filter Humus 1 Hr Nitrification Waste 1 Hr

8 2009 Denitrification Filter Online Mud Well (Backwash) Solids Cosettled in Primarys 2012 Digesters Off Line Stopped Heating/Digesting Needed cleaning (1 st in 25 Years) Needed $750,000 repairs/paint Started Hauling Primary 3% Fixed Cover Digester For Truck Loading

9 2013 Phosphorus Interim Limit Deal Total P ~ 2.7 mg/l (Typical Leaving Plant) Total P < 0.7 mg/l (Immediately 2 Months) Total P < 0.12 mg/l (@ Design Flow by 2022) Crash Course in Phosphorus Removal Biological Not a Option Chemical PACl o No Alkalinity impact o Dose After Trickling Filters o Buy Totes

10 Theoretical Dose: 0.87 lbs Aluminum per lb Phos Removed Actual = Theoretical X Multiplication Factor Multiplication Factor 0.7 Effluent 1.7 TF Eff SOLUBLE P

11 Spring 2013 Removing Phosphorus ~ 0.7 mg/l PACl Usage Close to Prediction lbs/day Intermediate Solids Summer 2013 Cosettling Failed Overnight Significant Odors Primary s/trickling Filters Lost Primary Sludge Blankets Odor Complaints / Newspaper Articles

12 Public Relations Neighbors Starting Hauling More Sludge Thinner 1-2% - $$$$ More Odor Control Chemicals Turned up Permangante Hypochlorite Few Others Adjusted Wasting Schedule Temporarily Stopped Cosettling Odors Subsided in Late Fall

13 Fall 2013 Fast Track 20-Yr Facilities Plan Eliminate Cosettling (& Odor Potential) o Install Rotary Drum Thickeners o $4,000,000 o 8-10 year Payback Eliminate Cosettling & Upgrade Digesters/Dewatering o 20 year payback

14 Designed/Bid Thickener& Odor Control Project Retrofitted Hypo Room gpm RDTs Thickeners Converted to Storage Tanks Odors Came Back Late Sept Blankets Up Project Awarded after November Referendum Passed

15 Retirements New Team Thickener Project in Construction No Major Odor Complaints Better Time Separation Humus / Nitrate Rich RAS Minimized Blankets Installed More Misting Systems

16 Odor Scrubber 2 RDTs and Polymer Upstairs Blowers Sludge Pumps in Basement 3 Aerated Sludge Storage Tanks

17 RDT Start Up Scheduled Next Week Facility Planning Complete Confirmed Fast Track Conclusions Digester Upgrade Not Cost Effective o No Sludge to Energy Project o Recycle Load (TKN) Cost Driver (50+ gal/day Methanol) Designing on Plant Upgrade Low Level Phos Ballasted Flocculation Pre-Selection Preview

18 Acknowledgements John DeGioia, Town of Southington James Grappone, Town of Southington George Pendleton, MCA & PhotoFlight - Shawn Shepard, Tighe & Bond - Rendering Discussion & Questions Frederick Mueller, P.E Tighe & Bond Middletown, CT famueller@tighebond.com