AWWA QTC98329

This paper describes the effect of the changes in the operation of conventional, sludge blanket, or solids contact clarifiers on water quality. The goals were to determine the changes in effluent concentrations of various contaminants when operational changes were made to the clarification process. Where possible, data was collected on treatment trains operating in parallel. Costs associated with the water quality improvements were calculated based on the results of the study. The first of three trials analyzed dual superpulsator trains with normal operations and with decreases in sludge blowdown frequency to determine what affects on water quality this intervention would have. Results indicate that decreasing the sludge blowoff time did not improve water quality when compared to normal treatment conditions. The focus of the second trial was to evaluate the impacts of powdered activated carbon (PAC) on water quality and operations of solid contact clarifiers. Water quality from normal operation conditions was compared to treatment when 5 mg/L of PAC was incorporated into the treatment scheme. Results did not suggest a significant improvement in total organic carbon (TOC), disinfection byproducts (DBPs) and DBP precursors as the result of PAC addition. The purpose of the third trial was to evaluate enchanced coagulation practices with that of the normal (baseline) treatment. In addition to evaluating enhanced coagulation practices, sludge blowdown times and PAC doses were varied. Results showed that with enhanced coagulation treatments TOC removal levels were increased on average by 7% in settled water and 8% in the effluent; however, turbidity levels suffered during this treatment scheme.

Product Details

Published:

01/01/1998

ISBN(s):

0898679796

Number of Pages:

53

File Size:

1 file , 440 KB