What is cleanfill?
Cleanfill materials are natural soils such as clay, soil, and rock, and some manufactured materials such as concrete, brick or tiles.
Cleanfill landfills are sites where only cleanfill material is accepted for disposal. Because of the type of material accepted, cleanfill landfills shouldn’t have any adverse effects on people or the environment.
However, many cleanfills mistakenly accept the wrong types of construction and demolition waste, contaminated soils, greenwaste, and other materials that can have an adverse effect on the environment.
What is not cleanfill?
Cleanfill must not include:
- Combustible, putrescible, degradable or leachable components
- Products derived from hazardous waste treatment
- Hazardous substances
- Liquid waste
- Contaminated soils (see more below)
Materials such as timber, metal, asbestos, greenwaste, household rubbish, road sweepings and foundry sand should not be accepted.
The Ministry for the Environment Guide to Management of Cleanfills provides more information on acceptable and unacceptable materials. (https://www.mfe.govt.nz/node/7425)
Heavy metals and organic contaminants can sometimes be found in soils. This is mainly due to historic practices where chemicals were manufactured, used, stored and disposed of in ways that are now considered unacceptable.
At high enough concentrations, these contaminants can be toxic to people and the environment. Contaminated soils should not be accepted at cleanfill landfills.
The Ministry for the Environment’s Hazardous Activities and Industries List (HAIL) outlines the types of activities that involve hazardous substance. Soil from sites with a history that includes a hazardous activity may have the potential to be contaminated. Any soil accepted from a HAIL site should be tested to make sure it is not contaminated.
Soils may naturally contain low concentrations of heavy metals. To differentiate between clean and contaminated soils, clean soils should only contain concentrations of heavy metals within the range that occurs naturally within the disposal area.
The historic pesticide DDT, which is widespread in the rural environment in very low concentrations, should be less than 0.35 mg/kg. Other man-made chemicals should be not be detectable when analysed at a lab.
The Regional Plan: Waste allows for the operation of cleanfill landfills as a permitted activity, provided sediment does not enter a water body.
To operate under the permitted activity rule, cleanfill landfills must be have effective erosion and sediment control measures in place and stringent waste acceptance criteria.
Cleanfill landfill operators need to ensure that only cleanfill material is accepted. This requires careful monitoring of incoming loads to make sure they do not contain unacceptable material. Some contaminated soils won’t be obvious, so the Otago Regional Council recommends frequent testing to ensure that the site doesn’t become contaminated.
If these requirements aren’t met, a consent is required. A consent application may be declined if the location of the landfill or material accepted isn’t suitable. Please call us on 0800 474 082 if you have any queries, and ask to speak with someone in our consents team.