Full Description

This article discusses pilot-plant studies conducted by the US Environmental Protection Agency's Drinking Water Research Division to evaluate the use of slow-rate filtration by small water systems for the removal of particulates, total coliforms, standard plate count bacteria, total organic carbon, and trihalomethane formation potential (THMFP). The article describes two pilot-plant scale filtration systems: a slow sand filter, operated for 800 days, and a second slow sand filter operated in parallel with a slow-rate filter containing granular activated carbon (GAC), operated for 200 days. Operating experiences and water treatment data for the two pilot systems are presented. Results indicate that slow sand filtration can be effective for turbidity, particulate, and bacterial control. Postchlorination could further reduce the bacterial densities of filter effluent. Small systems with a raw water containing high THMFP levels may not find slow sand filtration suitable for controlling THMs, but slow activated carbon filtration may provide the required control for THMs and other organics. The Drinking Water Research Division anticipates further studies of these pilot-scale filters. Includes 5 references, tables, figures.

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Edition: Vol. 76 - No. 12 Published: 12/01/1984 Number of Pages: 7File Size: 1 file , 1.5 MB