Recovery and reuse of coagulants from treatment of water and wastewater

The focus of water quality research in the decade ahead will emphasize the development of processes which will enable reclamation and reuse as opposed to wastewater treatment and disposal to a nearby water course. In th is regard the importance of chemical treatment processes similar to those utilized by the water utility industry for many years is now well established. Two problems in this type of system are the increasing expense and scarcity of appropriate chemicals and the resulting large volumes of sludge. The use of coagulant recovery techniques promise~ to alleviate both problems. Until economical coagulant recovery schemes have been developed, the potential benefits associated with water reuse cannot be fully realized.

The primary objectives of this research were to evaluate the possibilities and procedures for coagulant recovery in chemical treatment processes employed in water and wastewater treatment systems. Attention was focused on the extent of coagulant recovery achievable; the separation, dewatering, and ultimate disposal of the remaining solids after recovery; the effectiveness of the recovered coagulant during reuse; and the economic considerations which determine the feasibility of utilizing the proposed processes.