Definition - What does Underground Waste mean?
Underground Waste is a category of waste that has to be buried at certain depths beneath the earth's surface so that it does not contaminate underground water bodies. For disposal of oil and gas waste, class I and class II type disposal wells, also known as injection wells are used. The well is usually an oil or gas well which has been exhausted and before abandonment it acts as a disposal well.
Petropedia explains Underground Waste
Underground waste can be classified as:
- Municipal waste
- Chemical Waste
- Nuclear Waste
Municipal waste is treated and generally buried up to depths of 2000 feet, whereas industrial chemical and toxic waste is buried up to depths of 4000 feet and nuclear waste is deeply buried up to depths of 10000 feet or more.
Disposal wells are typically subjected to regulatory requirements as per the Environment norms. They are used for injecting high salt and minerals content water, and other impurities produced with hydrocarbons into the underground zones for safe and eco-friendly disposal of the unwanted materials extracted along with the hydrocarbons. Disposal wells are also known as Class II underground injection wells as they can be used to dispose of any fluid which is used in the extraction oil and gas. The oil and gas industry uses disposal wells to dispose the following:
- High salt content wastewater
- Heavy metals
- Radioactive materials