Kontek
Heavy Metal Removal
Reduction
Reduction is a process that adjusts the solution’s pH levels to change the waste particles’ chemical composition. It is most commonly used to extract heavy metals from water in aerospace engineering and metal finishing plants.
Caustic, acid and bleach additives quickly alter hexavalent chromium
Whereas hexavalent chromium is highly toxic, benign trivalent chromium appears in food and water. In order to transform chromium into its trivalent form, the solution’s pH needs to be elevated to very high levels. This is achieved by adding caustic soda powder. At the same time, bleach raises the tank’s oxidation reduction potential (ORP). By precisely adjusting ORP and pH levels, KONTEK’s system is able to transform hexavalent chromium into trivalent chromium before moving into the neutralization phase.
During neutralization coagulants and flocculants are added in sequence, compelling tiny chromium hydroxide particles to become denser particles that sink. Clarification removes these waste particles, leaving behind uncontaminated water that complies with environmental codes.
Source: http://kontekecology.com/heavy-metal-removal/