The monograph is devoted to the treatment of wastewater with coagulants and flocculants. The book analyzes the characteristics of wastewater contaminants removed using reagents, types, properties and methods for obtaining three groups of reagents: coagulants, flocculants and composite reagents based on them. Efficiency of application of separate groups of reagents for wastewater treatment is considered depending on their characteristics, type of contamination, technological parameters of treatment.