System Clogging - The Springfield Experience Nathan Hamm July - - PowerPoint PPT Presentation

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System Clogging - The Springfield Experience Nathan Hamm July - - PowerPoint PPT Presentation

Sep 25, 2023 252 likes •566 views

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

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SLIDE 1

Leachate System Clogging - The Springfield Experience

Nathan Hamm July 17, 2017

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SLIDE 2

MWCC 2017

Presentation Overview

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  • Facility Background
  • Challenges
  • Technical Approach
  • Findings
  • Remedial Approach
  • Design Recommendations
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MWCC 2017

Facility Background

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  • 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
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SLIDE 4

MWCC 2017

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Pump Station

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MWCC 2017

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Pumping System

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MWCC 2017

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Forcemain Construction

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MWCC 2017

Challenges

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  • 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
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MWCC 2017

Technical Approach

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  • 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
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MWCC 2017

Findings - Forcemain Pressure Test

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15 30 45 60 75 90 105 120 135 150 165 180 195 210 15 30 45 60 75 90 105 120 135 150 165 180 195 210 14:25 14:35 14:45 14:55 15:05 15:15 15:25 15:35 Pressure, PSI Time, Minutes

Forcemain Pressure Test Using Pump House Pumps

Pump 'AR-2" "AR-4' "AR-5" "AR-6" "AR-8" "AR-10"

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MWCC 2017

Findings - Forcemain Camera

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MWCC 2017

Findings - Leachate Analysis

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  • 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-CaCO3 and Siderite-FeCO3)

200 400 600 800 1000 1200 1400 Oct-01Oct-03Oct-05Oct-07Oct-09Oct-11Oct-13Oct-15 COD, mg/l

Chemical Oxygen Demand

50 100 150 200 250 300 Oct-01Oct-03Oct-05Oct-07Oct-09Oct-11Oct-13Oct-15 Ammonia as N, mg/l

Ammonia as N

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MWCC 2017

Leachate Lagoon Sludge

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MWCC 2017

Pumping System Strainer Basket Sludge

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MWCC 2017

Forcemain Sludge

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MWCC 2017

Forcemain Sludge

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MWCC 2017

Findings - Sludge Sampling and Analysis – EMSL Analytical

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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 Organic Matter 1 - 3% 1 - 2% Quartz 5 - 10% <1% Calcium Carbonate 30 - 40% 5 - 10% Mica <1% Iron Oxide 2 - 5% 40 - 50% Unidentified Inorganics 1 – 2% 10 - 20% Biological Organisms: Bacteria Trace Trace

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MWCC 2017

Findings - Summary

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  • 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

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MWCC 2017

Remedial Approach

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  • 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
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MWCC 2017

High Rate Flushing

Flushing Line North of AR-5 - Collecting with a Vac Truck

Location Station Valve Adjustment Dist to End, Feet Max Pressure, psi Flow Rate, gpm Gallons for

  • ne flush

# of Flushes Flush Time (min) Gallons Required Set Up Break Down, Hrs RT Haul, mi Load Rate Cycle Time, Hrs Pump Distance AR-3 to AR-5 26+00 Open AR-5 North Close AR-5 South Close AR-3 North Open AR-7 South Vac Truck at AR-5 Pump Truck at AR-3 8500 150 150 5548 1.5 55 8323 1.5 16 300 1.66 372 AR-3 to AR-1 (accounting for 6" pipe) 26+00 Open AR-5 South Close AR-3 South Open AR-3 North Close AR-1 North Vac Truck at AR-3 2234 150 150 2384 1.5 24 3575 1.5 16 300 0.83 372 Pump House to AR-1 26+00 Open AR-3 South Close AR-1 South Open AR-1 North Pump at AR-1 Vac Truck or Hose at PH 2600 200 150 1697 1.5 17 2546 1.5 5 100 0.99 200 Pump House to Leachate Pond Open AR-1 South Pump Truck at PH Open Suction Line Valve Pump to Leachate Pond 200 100 200 522 3 8 1567 1.5 5 100 0.99 20 Monitor Pressure at injection point Subtotal 104 min 16010 gal 6 hr 4 hr 12 hr Frac Tank Locations Totals 10 hr 107911 gal 19 hr 24 hr 53 hr 19

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MWCC 2017

Forcemain Pigging

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Foam Swabs and Scouring Pigs

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MWCC 2017

Forcemain Pigging

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Remote Tracking System

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MWCC 2017

Pigging - Launcher

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MWCC 2017

Pigging – Catcher System

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MWCC 2017

Pigging – Before and After Swabs

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MWCC 2017

Pigging – Before & After

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MWCC 2017

Lesson Learned – HDPE Restrictions

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MWCC 2017

Chemical Treatment

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  • Acid Blends
  • Large Volume Requirements
  • Safety Concerns
  • Disposal
  • Cost
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MWCC 2017

Overall Conclusions

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  • 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
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MWCC 2017

Questions

Nathan Hamm, P.E. SCS Engineers, Inc. 7311 W. 130th Street, Suite 100 Overland Park, KS 66213 nhamm@scsengineers.com (913) 749-0705 Direct Office Line

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