Combination of coagulating agents (aluminum sulfate and cationic polymer) for biosolids dewatering and its impact to odors

A combination of two conditioning agents, aluminum sulfate and cationic polymer were applied to dewater anaerobically digested biosolids to study their impact to dewatering properties of biosolids and to sulfur based odor generation from dewatered biosolids. Lower sulfur based odor compounds were measured from dewatered biosolids conditioned with greater amount of aluminum sulfate (alum) while higher cationic polymer dose resulted in more sulfur based odors from dewatered biosolids. More alum deteriorated biosolids dewatering properties while more cationic polymer improved dewatering rates for biosolids. Overall data suggest that there exists an optimum combination of alum and cationic polymer dose for better biosolids dewatering characteristics and less sulfur-based odor generation from dewatered biosolids.