Definition - What does Aquifer mean?
An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be extracted using water wells. Aquifers occur at various depths. Those closer to the surface are more likely to be used for water supply and irrigation. They are also likely to be topped off by local rainfall. Aquifers are a major source of water for industrial processing units as well as residential use; therefore, the quality and purity of these aquifers are of prime importance.
Petropedia explains Aquifer
Aquifers contain layers or zones below the earth's surface which are capable of yielding a significant amount of water. There are two types of aquifers:
- Unconfined aquifers- These are aquifers allow water to seep in from the ground surface directly above the aquifer.
- Confined aquifers- These aquifers have an impermeable dirt/rock layer that prevents water from seeping into the aquifer from the ground surface located directly above.
An aquifer can be contaminated by many things. Deliberate disposal of waste at point sources such as landfills, septic tanks, injection wells and storm drain wells can have an impact on the quality of the groundwater in an aquifer. Contaminants can reach the water table by any natural or man-made route along which water can flow from the surface to the aquifer.
Chemical substances found in water and sulfate reducing bacteria can corrode metal well casings in an oilfield. Mineral incrustation is a common problem in some shallow-water-table-type aquifers where there is an abundance of dissolved minerals including calcium, magnesium, iron and iron bacteria. When water is pumped from the well, changes in pressure and temperature occur. This creates ideal conditions for minerals to precipitate or settle out, causing scale formation on piping, fixtures and industrial equipment. Saline aquifers contain highly concentrated aqueous salts such as sodium chloride and calcium chloride, which have high potential for corrosion. Aquifer water needs to purified, demineralized and conditioned for industrial uses to avoid corrosion.