deep-well injection

Deep-well injection is a method of hazardous-waste management where liquid waste is pumped through a steel casing into porous rock formations deep underground. This process is relatively inexpensive and requires minimal pretreatment of the waste. However, it carries a significant risk of leaking and contaminating subsurface water supplies.1

This method is one of several land disposal options for hazardous wastes that are not destroyed by treatment processes like incineration. The injection zone must be located below an impermeable layer of rock or clay, potentially extending over half a mile below the surface. While fracking also involves injecting fluids underground, its primary purpose is to extract oil and natural gas, and it presents its own set of environmental concerns, including potential groundwater contamination and seismic activity. Brine solution mining, on the other hand, involves dissolving minerals to create underground caverns, often for storing brine or other substances.123