AWWA JAW56675

Although utilities strive to maintain water quality from thetreatment plant, through the distribution system, and intocustomers' homes and businesses, at times microbialindicators are present but go undetected in treated water. Thisresults in apparent contamination downstream in the distributionsystem.Causes of this contamination can be diminished by trackingand eliminating low-pressure events (including transitory ones),cross-connections, and inadequate disinfection procedures duringdistribution system maintenance. However, the complexity ofdistribution systems and the dispersion of related information,such as water quality, hydraulics, asset condition, and operationand maintenance, often prevent the causes of water qualityfailures from being identified. This lack of understanding of theorigin of positive coliform samples leads to a nonactive approachas long as the problem is not acute with regard to public health orcompliance issues.Key points to understanding and solving coliform existencein distribution system water include taking into account thehydraulics and daily operation and maintenance of storagetanks and pipe systems. The authors believe that analyzingcoliform problems is the first step toward solving them, andthey review the parameters involved in understanding andpredicting these problems. They also make a strong case forreplacing coliform testing with Escherichia coli-testing as aregulatory tool. Includes 151 references, tables, figures.

Product Details

Edition:

Vol. 94 - No. 8

Published:

08/01/2002

Number of Pages:

15

File Size:

1 file , 1.2 MB