The purpose of neutralisation is to adjust the pH value to meet the requirements of the different processing units in the wastewater treatment system.
Mining and some other industrial waste streams contain high concentrations of metals and sulphate. Elevated sulphate concentrations are normally associated with water from coal mining due to bacterial and chemical oxidation of pyrite (FeS), resulting in Acid Mine Drainage (AMD). AMD is formed when the mineral pyrite comes into contact with oxygen and water, producing elevated sulphate, metal and acidity concentrations.
As a result of the high concentrations of dissolved heavy metals and sulphate, these waters may not be discharged into public streams. This presents storage and management cost issues for industries.
Reduce Space Required By Brine Ponds and Evaporation Ponds
Desalination is an established technique of removing salts from water in order to produce ultrapure, drinking and process water (used for cooling towers, boilers, chillers etc). In addition to fresh water recovery, desalination offers additional benefits by cutting down disposal costs and the potential to recover valuable by-products from the waste stream.
Wastewater may contain valuable metals such as cobalt, copper, nickel and uranium which companies can reuse or sell once they are removed. The recovery of other saleable products, for example sulphur and calcium carbonate, from typical industrial wastes is also possible.
