<1ppm Phosphorus A BNR With No Chemical Addition Case Study

Transcription

1 WWOA 51 st Annual Conference October 2017 Arn Johnson Walker Process Equipment Div. of McNish Corp. 1

2 Todd Toelle, Superintendent City of Phillips, WI WWTP Chris Kaempfer, P.E. Kaempfer & Associates, Inc. Oconto Falls, WI Donald J. Heikkila, P.E. Ruekert & Mielke, Inc. Oconto Falls, WI Acknowledgements: Jeff Simpson & Karen Harter WWOA 2

3 City of Phillips Price Co. WI WWTP Plant Info mgd Avg. Annual Flow Max. Daily 1.2 Peak 1.4 Discharge to Elk Lake Current WPDES Limit mg/l CBOD Mo. Avg. 25 CBOD Wk. Avg. 40 SS Mo. Avg. 30 SS Wk. Avg. 45 Tot Phos. 6-mo. Avg 0.7 May Oct. Tot Phos. Mo. Avg 1.0 3

4 1980 s Plant Process Flow -Process incapable of year 2000 Nutrient Effluent Limits -Evaluate several process change options 4

5 OVERFLOW ~ <1ppm Phosphorus A BNR With No Chemical Addition SR/RBC Process SO 2 POLYMER WASTE PRIMARY SAMPLE SAMPLE AIR EFFLUENT FROM PHILLIPS PLATING CO. 18" INFLUENT SEWER BYPASS SCREEN SEWAGE INFLUENT SHREDDER FLOW METER INFLUENT PUMP STATION RAW SEWAGE PUMPS (3) BYPASS MECHANICAL BAR SCREEN SCREENINGS TO LANDFILL GRIT BLOWER BYPASS AERATED GRIT CHAMBER GRIT DEWATERING SCREW GRIT TO LANDFILL PRIMARY CLARIFIERS (2) BYPASS CONTACT TANK (4) BYPASS RBC UNIT AIR RBC AERATION BLOWERS (2) SECONDARY RBC CLARIFIERS UNIT (2) RETURN SECONDARY PUMPS (2) Cl2 CHLORINE CONTACT TANK 16" OUTFALL SEWER ELK LAKE WASTE SECONDARY M RETURN PRIMARY PUMPS (2) RETURN METER SUBNATENT RBC UNIT M PRIMARY METER WASTE METER DAFT M M THICKENED THICKENED PUMP METER THICKENER PUMPS Biological phosphorus removal was the Lowest Net Present Worth over 20-year Life. Add Return Sludge, Sludge Contact Tank and optimize operation no chemical addition Add DAFT for thickening waste secondary sludge WET WELL SUPERNATANT OVER FLOW ANAEROBIC DIGESTER TRANSFER PUMP RECIRCULATION PUMP HEAT EXCHANGER WASTE DIGESTED METER M STORAGE TANKS (2) INFLUENT SANITARY SEWER WASTE METER TO LAND M APPLICATION LOADING PUMPS (2) LEGEND CENTRIFUGAL PUMP BLOWER ROTARY LOBE PUMP Cl2 WASTEWATER, SCUM, & SUPERNATANT PARSHALL FLUME CHLORINE SOLUTION PROCESS FLOW SCHEMATIC M PROGRESSING CAVITY PUMP MAGNETIC FLOWMETER SO2 SULFUR DIOXIDE SOLUTION 5

6 - SCT design allows RSS to be added to any of 4 compartments and primary effluent to enter either half of the tank. Primary clarifier effluent presently mixes with RSS in the 1st compartment for anoxic reaction favorable for denitrification and SBOD 5 removal. - Flow then passes into anaerobic compartment with conditions favorable for phosphorus accumulating organisms (PAO), allowing phosphorus release and SBOD 5 removal. - Reactor compartments are mixed. Mechanical aeration is provided for any compartment to be aerated if additional aerobic treatment is needed. 6

7 30 year old RBC s replaced 4 compartment Sludge Contact Tank (SCT) -approx. 10,000 gal each 7

8 CONCENTRATION, mg/l <1ppm Phosphorus A BNR With No Chemical Addition PHILLIPS WASTEWATER TREATMENT PLANT EFFLUENT CHARACTERISTICS Historical BOD and SS effluent levels well below limits Historical Phosphorus effluent shown M S 93 M S 94 M S 95 M S 96 M S 97 M S 98 M S 99 M S 00 M S 01 M S 02 M S 03 M S 04 M S 05 M S 06 M S 07 M S MONTH PHOSPHORUS PROPOSED PHOSPHORUS LIMIT 1.6 PHOSPHORUS LIMIT Phosphorus Limit lowered to 1.0 mg/l and 0.7 mg/l in : SR/RBC BNR process operational, Phosphorus limit permitted at 1.6 mg/l 8

9 Jan thru mid 2017 Phosphorus consistently <1 mg/l year-round and < 0.7 on 6-mo. avg. May-Oct vintage Autotrol RBC s replaced 2015 with Walker Process Equipment EnviroDisc RBC s. Secondary Treatment Characteristic % Removal from Primary Effluent SBOD 5 96 TSS 92 TKN 81 N-NH 3 77 TP 90 Orthophosphate 91 9

10 Additional sampling and analysis was done during cold-water Winter months of 2016 along with Volatile Fatty Acid addition in the SCT to explore the relationship between low temperature/primary sludge fermentation organism dormancy and artificial VFA augmentation to feed the PAO. Somewhat surprisingly, the BNR did not deteriorate in colder water conditions. Thus the VFA addition had little effect. 10

11 SUMMARY BNR with RBC s and well engineered, modest investment process addition meet current Phosphorus standards -Potential Final Limit of 0.04 mg/l Total P would require new Tertiary Treatment 11

12 For More Information: COMPLETE CASE STUDY REPORT: Select: Literature Select: Featured Articles 1ppm EFFLUENT PHOSPHORUS FROM SR/RBC PROCESS - PLANT TRIAL RESULTS ENGINEERING: Chris Kaempfer, P.E. Kaempfer & Associates, Inc. (920) Donald J. Heikkila, P.E. Project Manager Ruekert-Mielke (920)