Pre-polymerised inorganic coagulants and phosphorus removal by coagulation - A review

This paper reviews the use of pn-polymerised inorganic coagulants in water and waste-water treatment, and discusses the removal of phosphorus by chemical precipitation and coagulation. Commonly used inorganic coagulants are aluminium or iron (IU) based salts, but a range of hydrolysed Al/Fe species. and not re Al/Fe salt itself, are responsible for the removal of impurities from water. By the development and use of polymeric inorganic coagulants, the coagulation performance can be improved significantly in some cases. Chemical precipitation and coagulation in phosphorus removal are two different processes. with the former related to the compound solubility acid the latter depending on the destabilisation-adsorption mechanism. Presently, there is uncertainty concerning the mechanisms and overall performance of phosphorus removal by pre-polymerised metal coagulants.