AWWA WQTC60689

This paper describes the experiences of a Florida utility before, during and afterconversion to chloramines as a secondary disinfectant. Background information for thedecision to switch from free chlorine residual to chloramines is discussed. The utilityexperiences high temperatures, significant total organic carbon (TOC) levels and varying water sources duringnormal operations.Descriptions of the following are included:development of remedial actions with specific water quality triggers;distribution system flushing operations; and,storage reservoir operation and monitoring.Extensive water quality monitoring programs were conducted to establish baseline waterquality prior to the change to chloramines. Organic, inorganic and microbiologicalparameters were monitored. Changes in distribution system water quality are describedincluding significant increases in total coliform and heterotrophic plate count (HPC) organisms. Change in disinfection byproduct (DBP)concentrations, variations in inorganic parameters, rapid chloramine residual loss, andnitrification are discussed. Customer complaints regarding taste & odor, and rusty waterwere also experienced.Significant biofilm characterization was done before and after the change in secondarydisinfectant using denatured gradient gel electrophoresis, phospholipid fatty acid analysisand other techniques. Samples were collected from pipe coupons removed fromdistribution system piping and from annular reactors located at various points in thesystem. In a cooperative study with the Centers for Disease Control, Legionella andMycobacteria populations in plumbing systems in large buildings and residences wereexamined to determine the impact of disinfectant change. Apparent increases in algae inthe distribution system after chloramination were observed. Includes 6 references, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

16

File Size:

1 file , 330 KB