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Transfer Stations and Landfills
Transfer Stations – What are they?
Transfer Stations are facilities which Council have placed around the district for people to take their refuse, garden waste and recyclables to. The refuse is transported to Oamaru Landfill for disposal, and the garden waste is either mulched on site, or transported to Oamaru Landfill where it is mulched and used to grow grass on the closed areas of the landfill. What happens to the recyclables is slightly different at each transfer station however there are no facilities to process these materials in the Waitaki District so the materials either get transported elsewhere in New Zealand or overseas for processing. Some transfer stations operate a second hand goods store where you can purchase items that have been dropped off.
Landfills – What are they?
Landfills are areas where rubbish is buried in the ground. Consents are required to operate a landfill, and strict guidelines must be adhered to.
Contaminants from the waste can seep into the ground and pollute groundwater (and some drinking water). These contaminants are called leachate. For this reason Oamaru Landfill has a leachate collection system in place to collect this “leachate” and it is sent to the sewage treatment plant for processing. Most modern landfills have a liner either clay or synthetic to prevent leachate from entering the ground, however Oamaru Landfill is an old landfill and was built before such ideas became into practise. Regular monitoring is undertaken around the site to ensure there are no adverse affects from leachate on the local groundwater.
When organic materials decompose in the absence of oxygen a gas called methane is formed. Methane is classed as a greenhouse gas, and has been linked to climate change. Most modern landfills require this gas to be collected and either burnt (which turns it into a less harmful gas, carbon dioxide) or is used for heating. Oamaru Landfill is too small to generate sufficient gas to collect. Never the less, Council wishes to minimise the amount of organic material which goes to landfill to reduce the generation of landfill gas, and to lower the risk of climate change. For this reason garden wastes are separated and mulched and used to grow grass on the closed parts of the landfill. By setting the charges for garden waste to be much cheaper than refuse charges, Council encourages people to separate their garden wastes out, and so reduces the formation of landfill gas.
When landfills are closed Council is obliged to monitor them to make sure there is no adverse affects on the environment, for many years to come. Due to the risks involved in landfills, these areas are generally not built on, and are of limited use to future generations.
Council is responsible for the care and monitoring of thirteen closed landfills in the Waitaki District.
Modern Landfills are very expensive to build. It is estimated that to build a new landfill in the Waitaki District would cost $20,000,000. On top of this the annual operating cost need to be added. It costs around $700,000 to operate Oamaru Landfill for one year. The operating costs for a new modern landfill is expected to be more expensive.
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