Tuesday, April 26, 2016

Groundwater Characteristics - PURICARE INDUSTRIAL ENTERPRISES Water Treatment Systems, Aganan, Pavia, Iloilo




Basic Groundwater Characteristics
Rain water that falls on porous terrains, such as sand or sandy loam, drains or percolates into the ground. In these cases, the water encounters a wide variety of minerals arranged in complex layers, or strata.
The minerals may include granite, basalt, and shale. In some cases, there may be a layer of very permeable sand beneath impermeable clay.
Ground water tend to be low in turbidity, high in dissolved minerals, and low in biological content than surface water.
In contrast to surface water, ground water sources are relatively free from suspended contaminants, because they are filtered as they move through the soil strata. This filtration also removes most of the biological contaminants. 
Some groundwater sources with a high iron content contain sulfate reducing bacteria. These are a source of fouling and corrosion in industrial water systems.
Groundwater may contain an undesirable level of scale forming solids, but due to its fairly consistent chemistry it may be treated effectively.
As groundwater encounters different minerals, it dissolves them according to their solubility characteristics. In some cases chemical reactions occur, enhancing mineral solubility.
A good example is the reaction of groundwater with limestone. Water percolating from the surface contains atmospheric gases. One of these gases is carbon dioxide, which forms carbonic acid when dissolved in water. The decomposition of organic matter beneath the surface is another source of carbon dioxide.  
Limestone is a mixture of calcium and magnesium carbonate. The mineral, which is basic, is only slightly soluble in neutral water. The slightly acidic groundwater reacts with basic limestone in a neutralization reaction that forms a salt and a water of neutralization. The salt formed by the reaction is a mixture of calcium and magnesium bicarbonate. Both bicarbonates are quite soluble. This reaction is the source of the most common deposition and corrosion problems. The calcium and magnesium (hardness) form scale on heat transfer surfaces if the groundwater is not treated before use in industrial cooling and boiler systems.
Structurally, limestone is porous. That is, it contains small holes and channels called "interstices". A large formation of limestone can hold vast quantities of groundwater in its structure. Limestone formations that contain these large quantities of water are called aquifers, a term derived from Latin roots meaning water bearing.
If a well is drilled into a limestone aquifer, the water can he withdrawn continuously for decades and used for domestic and industrial applications.
Unfortunately, the water is very hard, due to the neutralization / dissolution reactions described above. This necessitates extensive water treatment for most uses.



source: gewater.com


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