Leachate System Clogging - The Springfield Experience Nathan Hamm July 17, 2017 1
MWCC 2017 Presentation Overview • Facility Background • Challenges • Technical Approach • Findings • Remedial Approach • Design Recommendations 2
MWCC 2017 Facility Background • MSW Landfill • 120 Acres Pre-Subtitle D • 22.2 Acres Subtitle D • Historically Trucked Leachate to WWTP • Up to 15 MGY • Leachate Pumping System and Forcemain • Constructed in 2010 • Duplex Pump Station from Existing Storage Lagoon • 9 Mile, 4-Inch SDR 9 and SDR 17 HDPE Forcemain • Design Pump Flow 100 - 110 GPM (2.6 ft/sec) • >74M Gallons Pumped Since Commencement 3
MWCC 2017 Pump Station 4
MWCC 2017 Pumping System 5
MWCC 2017 Forcemain Construction 6
MWCC 2017 Challenges • July 2016 Leachate System Stops Operating • Pumps Ramp Up and Shut Down (High Pressure Limits) • City Attempts to Restore Service • Perform Pump Maintenance • Lagoon Intake Screen Dislodged • Turtles and Deer Bones • Attempts to Video / Camera Forcemain • Jetting Contractor Cleaned Select Section • Additional Clogs 7
MWCC 2017 Technical Approach • Determine Extent of Problem • Forcemain Pressure Analysis • Camera / Video Select Forcemain Sections • Assess Scale / Sludge Formation Mechanisms • Leachate Sampling and Analysis • Sludge Sampling and Analysis (Lagoons & Forcemain) • Develop Remedial Alternatives/Recommendations • Implement Selected Remedial Solutions 8
MWCC 2017 Findings - Forcemain Pressure Test Forcemain Pressure Test Using Pump House Pumps Pump 210 210 'AR-2" 195 195 "AR-4' 180 180 "AR-5" 165 165 "AR-6" "AR-8" 150 150 "AR-10" 135 135 Pressure, PSI 120 120 105 105 90 90 75 75 60 60 45 45 30 30 15 15 Time, Minutes 0 0 14:25 14:35 14:45 14:55 15:05 15:15 15:25 15:35 9
MWCC 2017 Findings - Forcemain Camera 10
MWCC 2017 Findings - Leachate Analysis • High TDS and Dissolved Metals • TDS 3,000 mg/L • Calcium, Iron, Magnesium, Sodium • Moderate to High Organics Concentrations • Scale Index Analysis and Precipitate Modeling • High Scaling Potential (Calcite-CaCO 3 and Siderite-FeCO 3 ) Ammonia as N Chemical Oxygen Demand 300 1400 Ammonia as N, mg/l 1200 250 1000 COD, mg/l 200 800 150 600 100 400 200 50 0 0 Oct-01Oct-03Oct-05Oct-07Oct-09Oct-11Oct-13Oct-15 Oct-01Oct-03Oct-05Oct-07Oct-09Oct-11Oct-13Oct-15 11
MWCC 2017 Leachate Lagoon Sludge 12
MWCC 2017 Pumping System Strainer Basket Sludge 13
MWCC 2017 Forcemain Sludge 14
MWCC 2017 Forcemain Sludge 15
MWCC 2017 Findings - Sludge Sampling and Analysis – EMSL Analytical Sample ID: 1 2 Description: Lagoon Sludge Forcemain Sludge Grouping Analyte Contribution Contribution Liquid Phase: Water 45 – 55% 35 - 45% Solid Phase: Plant Matter 1 - 3% 1 - 2% Decomposed 1 - 3% 1 - 2% Organic Matter Quartz 5 - 10% <1% Calcium Carbonate 30 - 40% 5 - 10% Mica <1% Iron Oxide 2 - 5% 40 - 50% Unidentified 1 – 2% 10 - 20% Inorganics Biological Bacteria Trace Trace Organisms: 16
MWCC 2017 Findings - Summary • Sludge / Sediment Buildup Throughout Forcemain • Loose Sludge with “Chips” vs. Hard Cementation • Heaviest Buildup in Middle Sections • Observed Scaling on Pipe Walls in Section Closest to Pumps • Significant Sludge Buildup in Lagoon (>18-Inches) • Sucked into Pumping System • Sludge Chemical Composition Different Between Lagoon and Forcemain • Leachate Conducive to Precipitate Scale Formation 17
MWCC 2017 Remedial Approach • Modify Lagoon Intake Structure • Phased Cleaning Approach • High Rate Flushing and Suction • High Pressure Jetting • Chemical Cleaning (Acid Treatment) • Camera the Pipes After Cleaning to Observe Effectiveness • Develop a Long-Term Routine Maintenance Program • Pigging • Lagoon Aeration • Routine Flushing or Jetting • Chemical Scale Inhibitors • Biocides 18
MWCC 2017 High Rate Flushing Flushing Line North of AR-5 - Collecting with a Vac Truck Max Dist to End, Pressure, Flow Rate, Gallons for # of Flush Time Gallons Set Up Break Cycle Pump Location Station Valve Adjustment Feet psi gpm one flush Flushes (min) Required Down, Hrs RT Haul, mi Load Rate Time, Hrs Distance Open AR-5 North Close AR-5 South Close AR-3 North Open AR-7 South Vac Truck at AR-5 AR-3 to AR-5 26+00 Pump Truck at AR-3 8500 150 150 5548 1.5 55 8323 1.5 16 300 1.66 372 Open AR-5 South Close AR-3 South AR-3 to AR-1 Open AR-3 North (accounting for Close AR-1 North 6" pipe) 26+00 Vac Truck at AR-3 2234 150 150 2384 1.5 24 3575 1.5 16 300 0.83 372 Open AR-3 South Close AR-1 South Open AR-1 North Pump at AR-1 Pump House to AR-1 26+00 Vac Truck or Hose at PH 2600 200 150 1697 1.5 17 2546 1.5 5 100 0.99 200 Open AR-1 South Pump Truck at PH Pump House to Open Suction Line Valve Leachate Pond Pump to Leachate Pond 200 100 200 522 3 8 1567 1.5 5 100 0.99 20 Monitor Pressure at 104 min 16010 gal 6 hr 4 hr 12 hr injection point Subtotal 10 hr 107911 gal 19 hr 24 hr 53 hr Frac Tank Locations Totals 19
MWCC 2017 Forcemain Pigging Foam Swabs and Scouring Pigs 20
MWCC 2017 Forcemain Pigging Remote Tracking System 21
MWCC 2017 Pigging - Launcher 22
MWCC 2017 Pigging – Catcher System 23
MWCC 2017 Pigging – Before and After Swabs 24
MWCC 2017 Pigging – Before & After 25
MWCC 2017 Lesson Learned – HDPE Restrictions 26
MWCC 2017 Chemical Treatment • Acid Blends • Large Volume Requirements • Safety Concerns • Disposal • Cost 27
MWCC 2017 Overall Conclusions • Analyze Leachate for Scaling Potential During Design • Design Forcemain Systems for Sediment Resuspension • > 3.5 ft/sec for loose scale removal and resuspension • < 8 ft/sec to avoid excess head and water hammer • Forcemain Pipe ≥ 4 -inch Diameter to Facilitate Maintenance • Design for Maintenance • Cleanouts Spaced 400-500 ft Maximum • Pig Launchers and Catchers • Chemical Treatment Equipment • Develop and Follow a Routine Maintenance Plan 28
MWCC 2017 Questions Nathan Hamm, P.E. SCS Engineers, Inc. 7311 W. 130 th Street, Suite 100 Overland Park, KS 66213 nhamm@scsengineers.com (913) 749-0705 Direct Office Line 29
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