Generalities of the Coagulation-Flocculation Process: A Perspective on Biocoagulants

Water treatment is a necessity for social and industrial development. Coagulation-flocculation is a fundamental process for the reduction of colloidal particles present in the water to be treated. The use of synthetic coagulants in effluent or wastewater treatment leads to a high production of non-biodegradable sludge and water containing trace elements that are harmful to ecosystems. Biocoagulants are a very efficient alternative that produces a low volume of sludge and has no harmful effects on flora or fauna. This chapter presents the generalities of the coagulation-flocculation process related to water treatment and identifies the advances in the field of biocoagulants. The chapter develops theoretical aspects of colloidal systems, their stability, and the interactions between particles. The coagulation-flocculation process is also described, as well as the influencing factors (temperature, pH, water composition, among others). Finally, the kinetic aspects of the processes of colloidal destabilization, floc formation, and sedimentation are described.