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Long-Term Leachate Management at the Tom Howe Landfill Site Kaela Roelens Haldimand County MWA Spring Workshop May 2014
Long-Term Leachate Management at the Tom Howe Landfill Site
Long-Term Leachate Management at the Tom Howe Landfill Site
Kaela Roelens Haldimand County
MWA Spring Workshop May 2014
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Background• Owned by Haldimand County & Norfolk County• Location: Part Lots 7&8 Concession 15 Walpole• Incoming waste from Haldimand County, Norfolk County, & Mississaugas of the New Credit First Nations.• Annual waste tonnage ~35,000 tonnes; anticipated closure: December 2015.• Current on-site leachate storage: 6 x 57m³ tanks = 342m³. Controlled by SCADA.• From 2008-2012 average hauled annual leachate volume: 67,000m³• Leachate Quality – ammonia is the key loading parameter in terms of WWTF impact, ~285 mg/L
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Managing Leachate On-SiteNeed: free up WWTF capacity, reduce hauling/ treatment costs, and accommodate leachate treatment post closure. How? Options - 1.Reduce volume of leachate through evapo-infiltration ponds; spray irrigation; poplar tree plantation2.Manage peak leachate volumes through additional on-site storage tanks; leachate ponds; hauling schedule3.On-Site treatment through mechanical/ chemical/ biological system; pre-treatment wetland; treatment lagoon; air stripping; breakpoint chlorination
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Preferred Approach• The following combination of options are explored for use at Tom Howe:
1. On-site pre-treatment
• Pre-treatment wetland
• Pre-treatment aerated lagoon (which may be used in combination with wetland)
2. On-site recirculation/irrigation
• Other alternatives will not reduce overall hauled leachate volumes, or involve treatment systems requiring significant operator control not appropriate at a closed landfill site.
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Leachate Pre-Treatment Wetland
• Sub-surface System: Leachate trickles through a media filter and wetland and is collected in a lagoon
• Anticipated 50% reduction of influent leachate flow rate
• Allows for reduction of ammonia loading through biological nitrification
to WWTF
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Leachate Pre-Treatment Wetland• Design based on:
• Influent flow of 220m³/day
• Influent ammonia of 285 mg/L
• *Effluent ammonia target of 50 mg/L
• Effluent flow target of ~110m³/day
• Leachate temperature of 5ºC
• This would result in a wetland with surface area of 6,300m², 1m depth• Preliminary construction cost: $1,280,000• Annual O&M costs: $80,000
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Leachate Re-Circulation & Poplar Plantation
• Leachate re-circulation: re-applying collected leachate to the waste fill areas to reduce volume through evaporation, transpiration and infiltration.
Examples include: injection, surface drip application/ irrigation, spray irrigation, surface evapo-infiltration ponds, mix leachate with incoming waste.
• Leachate percolates through waste which may improve leachate quality overtime by slowly degrading the waste mound.• Poplar plantation can be used in combination or alone
Alternate cap; intercept leachate plumes; leachate irrigation plantation.
Leachate Re-Circulation & Poplar Plantation Cont’d
• Poplar trees – 4,000/hectare or 1.5m spacing• Long-term leachate production – ~6,000m³/month• Residual leachate uptake - 300 L/tree/month• # of trees required to manage leachate on-site – 20,000 or 5 hectares of trees• Cost to purchase tree & prep ground – ~$120,000 • Total Cost of whips and drip irrigation system - $740,000• If combined with pre-treatment wetland, total costs would be reduced to $370,000
SummaryCombination of pre-treatment wetland and poplar plantation:• TOTAL Construction: $2,140,000 • TOTAL Annual O&M: $160,000
Next Steps• Pilot project to determine feasibility at Tom Howe
Benefits
• Frees up capacity at WWTF’s• Less ammonia loading to the WWTF’s• Reduction in hauling/ treatment costs• Less truck traffic
MWA Spring Workshop May 2014MWA Spring Workshop May 2014
Questions?Kaela Roelens – Waste Mgmt Tech.
Haldimand CountyP: 908-318-5932 Ext. 6222
Bruce Gall – UEM ConsultingE: [email protected]
