Polymers for Coagulation and Flocculation in Water Treatment

Abstract

The desires to improve on the operational efficiency of coagulation/ flocculation (CF), a unit process in water and wastewater treatment, and to obviate the other challenges synonymous with the use of inorganic coagulants (i.e. alu- minium- and iron-based alum) impelled the search for alternative coagulants that can ameliorate the identified shortcomings. Amongst the array of synthetic and natural origin materials that have been screened as alternatives to the conventional inorganic alum, polymeric coagulants have shown better promise. The inherent structural features of polymeric coagulants enhanced the CF process operation and economy. This treatise is an exposition on the variables that define the choice of polymeric coagulant as an alternative to the conventional inorganic coagulants. The theoretical bases for the choice of the different polymeric coagulants were dis- cussed. Using the identified active coagulating species in the different polymeric coagulant as a premise, the underlying CF mechanisms in the use of this genre of coagulants were expounded. The research gap in the use of polymeric coagulant as substitute to the conventional inorganic coagulant was also highlighted