AWWA WQTC50377

Powdered activated carbon (PAC) treatment technology was evaluated for its capability in removing the taste-and-odor causing compounds in Detroit River source water under various process conditions. Impacts from the operational factors were investigated through statistical experimental design. Chlorine and PAC interaction was found to be critical in determining the feasibility of applying PAC for taste-and-odor (T&O) control for the four water plants at the Detroit Water and Sewerage Department (DWSD). The PAC-chlorine interaction reduces the PAC adsorption of odorants and lowers the chlorine residual. Such interaction intensifies under high PAC dose and chlorine doses; therefore, neither adding more PAC nor increasing chlorine dose can achieve both goals of T&O control and Ct compliance. Chlorine decay was evaluated under various PAC and chlorine doses. The relationship between the PAC dose and the required initial chlorine dose to meet the minimum Ct requirement was also developed. The current practice of adding PAC to rapid mix may require up to 10 mg/L chlorine dose during T&O episodes, in order to satisfy the Ct requirement. PAC removal of odorant may only be effective and feasible if PAC-chlorine interaction is completely avoided. For the DWSD plants, it may be achieved by practicing intermediate chlorination and retrofitting the clearwells. Includes 4 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

01/01/1999

File Size:

1 file , 270 KB