- Injection well
An injection well is an underground
well into which water, other liquids, or gases are injected instead of being pumped out.Applications
Injection wells are used for many purposes. One of these is
waste water dumping, in which waste water is injected into the ground between impermeable layers of rocks to avoid pollutingfresh water supplies. In this case, when the injection well is full, it would becement ed to seal it to avoid leakage from the injection point.Another use of injection wells is in
petroleum production. Steam,carbon dioxide , water, and other substances can be injected into an oil-producing unit in order to heat the oil and/or lower its viscosity, allowing it to flow to a producing well nearby.Yet another use for injection wells is in environmental remediation, for cleanup of either soil or groundwater contamination. Injection wells can insert clean water into an
aquifer , thereby changing the direction and speed of groundwater flow, perhaps towardsextraction well s downgradient, which could then more speedily and efficiently remove the contaminated groundwater. Injection wells can also be used in cleanup of soil contamination, for example by use of an ozonation system. Complexhydrocarbons and other contaminants trapped in soil and otherwise inaccessible can be broken down byozone , a highly reactive gas, often with greater cost-effectiveness than could be had by digging out the affected area. Such systems are particularly useful in built-up urban environments where digging may be impractical due to overlying buildings. [ [http://yosemite.epa.gov/opa/admpress.nsf/6427a6b7538955c585257359003f0230/7bfcdcd6fef70da285257163005c159c!OpenDocument East Islip Superfund Site cleanup] ; example of use of ozonation wells for remediation in situ]Theoretically, a injection well is a safe way to dump waste waters as wastes are injected into layer of rocks where water can't go through and building an injection well is strictly controlled, however injection wells are known to be prone to leaking because of
earthquakes andfractures in the rock structure.Regulatory requirements
In the United States, injection well activity is regulated by the
United States Environmental Protection Agency (EPA) and state governments under theSafe Drinking Water Act . EPA has issued Underground Injection Control (UIC) regulations in order to protect drinking water sources.Notes
References
* [http://www.frtr.gov/matrix2/section4/4-54.html Deep Well Injection]
* [http://www.pollutionissues.com/Ho-Li/Injection-Well.html Injection Well]External links
* [http://www.epa.gov/safewater/uic EPA - Underground Injection Control Program]
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