Presentation on theme: "On-Site Leachate Management RM of Tache Pilot Study."— Presentation transcript:
On-Site Leachate Management RM of Tache Pilot Study
Leachate Any liquid that is in contact with refuse –Waste will absorb moisture up to its field capacity. Beyond this point, any additional moisture will contribute to leachate (not accounting for channelling).
Quantity of Leachate Function of: Landfill size (footprint) Water Balance (precip, evap) Runoff/surface water shedding Water content of incoming waste –Incoming waste typ 20% moisture –Field Capacity typ 55% moisture
Leachate We can influence the amount we generate,but We can’t ‘stop the flow’
Operations to Minimize Leachate Generation Minimize active face area Cover daily Grade intermediate slopes to shed water
Leachate Management Through design and operations, the objective is to minimize leachate What can we do with the leachate we do generate?
Leachate Currently allowed in MB: –Spectre of no treatment permitted in MWWTP –No recirculation –Not acceptable to exfiltrate from base of landfill –No purpose made leachate treatment facility in MB
Leachate So what do we need to have happen?
Leachate The Province can’t write a law that prohibits landfills from generating leachate so We need to create options for leachate treatment/management
Leachate Management On site storage (tank, pond, sump) Off site treatment (WTP) On site management –bioreactor –evaporation pond –on site treatment plant
Leachate Management off site transportation costs and risk treatment cost sludge and effluent disposal on site --- desireable
On site Treatment For practical/ cost reasons this is rarely selected Complexity of operation Availability of Municipal wastewater treatment plant capacity
Problems with using Municipal plants Allocation of available municipal treatment plant capacity to high strength leachate Limitations of loading rates to plants Loss of municipal plant capacity for conventional community growth
Leachate In the interim, what do landfill operators do? Ones that own MWWTPs still use that option ( sunsetting) Ones that don’t have MWWTPs?? [ie. municipalities and private]
Typical Leachate Treatment in Manitoba Trucked to MWWTP ( sunsetting) No removal from landfill On site holding Other?? Unreported action
Here’s an option Overview of Pilot Study of Evaporation Pond and Treatment in the RM of Tache Description of Operations Operating Parameters Summary of Pilot Study 7 Years of operation –Quantity –Quality Observations
On Site Leachate Volume Reduction Use the net water deficit opportunities Mid west region application
RM of Tache Pilot study began in 2002, under the authority granted by MBC. Primary function of the evaporation pond; - reduce the quantity of leachate to be treated, and, - to improve the quality for ultimate discharge. Leachate from waste cells is pumped to evaporation pond. Evaporation pond equipped with spray nozzles to evaporate the liquid.
Water Balance June thru Sept net water deficit: Winnipeg / Steinbach records June 68.8 mm July89.8 mm August71.8 mm Sept43.9 mm
Waste Cell Waste Cell Evaporation Pond Retention Pond Site Plan
Operation Goals On-site responsibility for leachate management; Optimize leachate volume reduction; Elimination of chemicals addition for treatment of leachate or hauling to WWTP; Acceleration of leachate stabilization. Pretreatment of leachate on-site to reduce biological load; Minimize long-term liability.
Nozzles and Water Droplet Design Spray Nozzle Spray Pattern
Description of Operations Operational monitoring requirements includes recording: –Precipitation, wind speed, ambient temperature, –Daily time (duration) of aeration pump operation and pond gauge reading, –Data collecting: physical – chemical analysis, –Volume of transferred liquid from EP to Retention Pond at the end of operation seasons.
Operating Parameters On average 100 kPa (15 psi) in the sprayer/by-pass circuit with leachate spraying (< 1m high), permit continuous operation of the EP If, with the “by-pass” opened, the spray from the evaporation pond drifts beyond the top of the berm, the sprayer pump shall be turned off. Hours of operation of the sprayer system will be recorded on the “Leachate Pond Operating Record”, which is maintained by landfill operators
Monthly Volume of Liquid Processing in Evaporation Pond
Summary of 2008 Pilot Study Quantity ParameterValue Volume leachate pumped to evaporation pond: 1,440 m 3 Volume of rainfall accumulation in evaporation pond: 690 m 3 Volume of liquid managed in evaporation pond: 2,130 m 3 Volume of liquid evaporated:1,470 m 3 Average daily evaporation rate:9.5 m 3 /day
Quantity of liquid processing in Evaporation Pond ( Year)
BOD and TOC over time in Evaporation Pond for 2008
Observations For 2008 Pilot Study, 2,130 m 3 of liquid was managed in the evaporation pond and 1,470 m 3 of liquid was evaporated (9.5 m3/day) Organic content expressed as BOD and TOC were reduced in the operation of the spray evaporation pond.
The spraying/evaporation process is enabling significant biological stabilization of organic content. This is considered to be due to anaerobic stabilization of organics, as the leachate resides in the landfill waste mass, prior to extraction. Dissolved metals are precipitating as metal sulphides as pH is adjusted ‘up’ in the spray pond. Summary of Pilot Study - Quality
Typical leachate generation rates; 200 to 500 cu m/ha/yr Tache 600 cu m/ha/yr Total evaporation achieved 6 cu m/1000m2 evap pond/day Using 100 operating days, evaporation pond sizing 1 ha evap pond per 10 ha landfill Pilot Study- Design Parameter Development
Go Forward Challenges End of operating season –Off site haul for treatment? –Where to? –Quality for surface discharge? –Return to Landfill –Is return flow recirculation? Current attitude of regulator Options for Operators/Owners