METHOD FOR PLANT-SPECIFIC OPTIMIZATION OF POLYMER USE IN CONDITIONING OF TREATMENT RESIDUALS

Management of water treatment residuals is receiving increased attention for a variety of reasons, including the inability to directly discharge or recycle waste streams, and the need for drier solids for purposes of residuals transport, landfilling, disposal, or coagulant recovery. While much research has been performed to characterize the physical and chemical properties of water treatment residuals after dewatering, little information is available that would aid in actually optimizing the polymer addition prior to residuals dewatering. Yet, this step is crucial in obtaining a cost-effective and environmentally acceptable waste product.What can be done to bring down the costs and difficulties associated with residuals conditioning and dewatering, or even work towards optimizing these processes? A recent AWWARF-sponsored research project has developed a general approach, or protocol, for accomplishing this, and it is presented in this paper. It includes methods for defining process objectives, assessing current performance, evaluating the potential for improvement, characterizing the effects of variable flows and solids properties, determining if a change in polymer would be advantageous, and possible means of improved polymer dose control. The overall approach is flexible in order to be plant-specific, and is presented in a user-friendly context.