Hamilton City Council is working on improving leachate levels at the Horotiu landfill.
A monthly report to Environment Waikato’s Regulatory Committee this week said leachate pumping capacity remained a concern to Environment Waikato staff.
The council is introducing measures to ensure full compliance soon, and Hamilton City Council’s Water and Waste Services Manager Leroy Leach outlined the actions proposed. These included partial capping of 75 percent of Stage 4 to reduce leachate which would completed next month. Gas from this stage would be reticulated and flared off by July to reduce greenhouse gases and control odour.
A system to turn landfill gas into electricity would begin in September. Meanwhile the council was using tankers and on-site open tanks for leachate storage. New pipework would be established in June and daily checks were being made on the leachate pumping stations.
Cutoff bunds and additional catchpits had been installed to deal with stormwater and leachate levels and were now being monitored weekly, he said.
Environment Waikato Resource Officer Barry Campbell told the meeting that landfill operations had continued to be acceptable in the last month, with low odour levels and improved burial of special wastes. Leachate depths had increased following the wettest February on record for over 100 years.
He said Environment Waikato staff previously had concerns about the ability of Stage 6 to store leachate in wet weather, as the extraction system was under-designed and prone to clogging. Recent improvements in management at the site have resulted in less likelihood of problems in the future.
The Regulatory Committee heard actions that Hamilton City Council was undertaking at the landfill to ensure that leachate levels were reduced. Leachate levels were the single outstanding issue with the landfill, as covering of the rubbish was much improved, and there was little problem with flies and gulls, he said.