07-12-2012, 06:19 PM
Electrocoagulation?
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What is Electrocoagulation?
Electrocoagulation, also known as Radio Frequency Diathermy or Short Wave Electrolysis, is a technique used for wash water treatment, wastewater treatment, industrial processed water, & medical treatment. Electricity-based electrocoagulation technology removes contaminants that are impossible to be removed by filtration or chemical treatment systems, such as emulsified oil, TPH, suspended solids, and heavy metals. Fully automated, modular system has no filters to clean or replace and does not require use of chemicals.
The Electro coagulation process is based on valid scientific principles involving responses of water contaminants to strong electric fields and electrically induced oxidation and reduction reactions. This process is able to take out over 99 percent of some heavy metal cations and also appears to be able to electrocute microorganisms in the water. It is also able to precipitate charged colloids and remove significant amounts of other ions, colour, colloids, and emulsions.
Electro coagulation systems have been in existence as early as 1900 using a variety of anode and cathode geometries, including plates, balls, fluidized bed spheres, wire mesh, rods, and tubes.
Electrocoagulation in water treatment
With the latest technologies, reduction of electricity requirements, and miniaturization of the needed power supplies, EC systems have now become affordable for water treatment plants and industrial processes worldwide.
Background
Electrocoagulation (Electro meaning to apply an electrical charge to water and Coagulation meaning the process of changing the particle surface charge, allowing suspended matter to form an agglomeration) is an advanced and economical water treatment technology. It effectively removes suspended solids to sub-micron levels, breaks emulsions such as oil and grease or latex, and oxidizes and eradicates heavy metals from water without the use of filters or the addition of separation chemicals.
A wide range of wastewater treatment techniques are known, which includes biological processes for nitrification, denitrification and phosphorus removal, as well as a range of physico-chemical processes that require chemical addition. The commonly used physico-chemical treatment processes are filtration, air stripping, ion exchange, chemical precipitation, chemical oxidation, carbon adsorption, ultra filtration, reverse osmosis, electro dialysis, volatilization, and gas stripping.
POSSIBLE MECHANISMS
The pH, pollutant type and concentration, the bubble size and position,floc stability and agglomerate size all influence the operation of the electrocoagulation unit. The complexity and number of possible interactions are highlighted in Figure 1. The overall mechanism is a combination of mechanisms functioning synergistically. The dominant mechanism may vary throughout the dynamic process as the reaction progresses. The dominant mechanism will almost certainly shift with changes in operating parameters and pollutant types.