Long-Term Leachate Management at the Tom Howe Landfill Site Kaela Roelens Haldimand County MWA 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 Current on-site leachate storage: 6 x 57m³ tanks = 342m³. Controlled by SCADA. From 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 2014 Managing Leachate On-Site Need: 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 plantation 2.Manage peak leachate volumes through additional on-site storage tanks; leachate ponds; hauling schedule 3.On-Site treatment through mechanical/ chemical/ biological system; pre-treatment wetland; treatment lagoon; air stripping; breakpoint chlorination

MWA 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 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 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 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 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

Summary Combination 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 2014 Questions? Kaela Roelens – Waste Mgmt Tech. Haldimand County P: Ext E: OR Bruce Gall – UEM Consulting E: