AWWA JAW20914

Laboratory and field studies were conducted to determine the impact of granular activated carbon (GAC) drinking water filters and various operational variables on the release of populated filtration medium into finished water. Initially, various filtration media were compared. In laboratory column experiments, the surfaces of GAC, sand, and anthracite particles were populated to the same level with heterotrophic plate count (HPC) bacteria. However, GAC supported greater numbers of the coliform Klebsiella oxytoca than the other two media. A comparison of the media from operating drinking water filters showed that GAC-filtered water contained particles with attached HPC and coliform bacteria to a greater extent than sand- and anthracitetreated water. The involvement of various operational variables in the increased release of populated fines was evaluated at two facilities. Statistical analyses showed that GAC age does not affect the occurrence of populated fines in filtered water. However,a deeper GAC bed, an increase in applied water turbidity,and an elevated filtration rate were implicated as contributing to the presence of populated filtration medium in drinking water. Includes 27 references, tables.

Product Details

Edition:

Vol. 79 - No. 5

Published:

05/01/1987

Number of Pages:

5

File Size:

1 file , 1.2 MB