AWWA ACE91001

A host of regulatory guidelines for wastewater treatment plant sludges are now being applied to water treatment plant sludges. In addition, the nature and volume of wastes generated by water treatment plants is likely to change as utilities optimize and modify treatment processes to meet Safe Drinking Water Act regulations. As existing facilities renew their permits and new facilities go on-line, there is an increasing focus on evaluating residuals treatment and disposal alternatives with particular emphasis on impacts from discharges. This paper provides an overview of existing residuals management practices, a review of regulations that impact past practices, and a discussion of remedial handling, treatment and disposal technologies available for handling water treatment plant wastes. The author believes that mechanical dewatering will become the solids treatment process of choice at most existing facilities; a number of processes for dewatering sludge are briefly described. A table lists seven water treatment processes and the characteristics of the waste streams resulting from each process; the probable contaminants, disposal methods, and regulations for each are identified. A second table gives the aquatic life chronic criteria guidelines for a number of compounds. A third table lists the regulatory limits (in mg/L) of several hazardous constituents. A decision tree shows the steps involved in planning for coagulant sludge disposal.