Aluminum hydrolysis effects on phosphorus removal from wastewaters

Summarization: The effectiveness of the aluminum hydrolysis species in phosphorus removal from wastewater was examined. These species were formed by partially neutralizing an aluminum chloride solution under controlled conditions and called polymerized basic aluminum chloride (PBAC). The results were compared with those for alum, the most common aluminum coagulant. Supernatant suspended solids removal, settling rates, sludge filtrability, and organics removal were evaluated. The factors that affected the efficiency of the coagulants were: the molar ration of hydroxide to aluminum in the preparation of PBAC; the molar ratio of aluminum to phosphorus; pH; and the presence of other ionic species. Phosphorus removal could be adequately explained by complex formation and precipitation. The removal of organics could not be attributed to a strictly chemical interaction.Presented on