Vermont Agency of Natural Resources drafts new Underground Injection Control (UIC) Regulations. Injection wells are classified by the U.S. Environmental Protection Agency into six classes according to the type of fluid they inject and where the fluid is injected, as follows:
- Class I wells – inject hazardous and non-hazardous wastes below the lowermost underground source of drinking water (USDW). Injection occurs into deep, isolated rock formations that are separated from the lowermost USDW by layers of impermeable clay and rock.
- Class II wells – inject fluids associated with oil and natural gas production operations. Most of the injected fluid is brine that is produced when oil and gas are extracted from the earth.
- Class III wells – inject super-heated steam, water, or other fluids into formations to extract minerals. The injected fluids are then pumped to the surface and the minerals in solution are extracted. Generally, the fluid is treated and re-injected into the same formation.
- Class IV wells – inject hazardous or radioactive wastes into underground sources of drinking water. These wells are banned under the Underground Injection Control (UIC) program because they directly threaten public health.
- Class V wells – are injection wells that are not included in the other 4 classes. Some Class V wells are wastewater disposal wells used by the geothermal industry, but most are wells such as septic systems and cesspools. Generally, they are shallow and depend upon gravity to drain or “inject” liquid waste into the ground.
- Class VI wells – inject carbon dioxide (CO2) into deep underground subsurface rock formations for long-term storage, or geologic sequestration. The Division does not have primacy to regulate Class VI wells. Class VI wells are permitted and regulated though the US EPA.
Mark Bannon sits on the State Technical Advisory Committee and will review and comment on new regulations. Check back on the Bannon Engineering website for updates.