Within the past few decades, the realization that subsurface injection could
contaminate ground water has prompted many states to develop programs and
methods to protect underground sources of useable water. Additionally, to
increase ground water protection, a federal Underground Injection Control (UIC)
program was established under the provisions of the Safe Drinking Water Act (SDWA)
of 1974. This federal program establishes minimum requirements for effective
state UIC programs. Alabama has EPA’s approval to run the UIC program in the
state. Since ground water is a major source of drinking water in Alabama, the
UIC program requirements were designed to prevent contamination of Underground
Sources of Drinking Water (USDW) resulting from the operation of injection
wells.
What is An Underground Injection Well?
Most of the injection wells regulated by ADEM, are designed much like the
gravity flow field lines used to dispose of domestic wastewater from a home.
Common uses are for treated discharges from small car washes and laundromats
that are located in an area where a public sewer system is not available. There
are also treated discharges from small wastewater collection and treatment
systems for residential areas, and discharges of treated groundwater from
systems designed to cleanup groundwater contamination.
When properly sited, constructed, and operated, injection wells can be an
effective and environmentally safe means of fluid waste disposal. There are many
different types of injection wells, but they are all similar in their basic
function. The federal and Alabama UIC program has grouped injection wells into
five categories:
Class I Wells: Injection of
pollutants below an USDW. These wells are prohibited by regulation in Alabama
Class II Wells: Injection of
wastes from oil & gas productions. The Alabama Oil & Gas Board regulates these
types of wells.
Class III Wells: Solution mining
of certain minerals. Alabama currently regulates one facility with this type of
well. Fresh water is injected to dissolve minerals, such as salt, and the salt
solution is used as a raw material in a manufacturing process.
Class IV Wells: Injection of
Hazardous Waste above an USDW. These wells are banned nationally by Federal
regulations. If any are found, they are required to be closed.
Class V Wells: All other types
of wells not regulated as a Class I, II, III or IV well. These make up about 90
% of permitted injection wells in Alabama.
