AWWA WQTC55010

The purpose of this study was to provide documentation describing the investigation into the nature, extent, and cause of the material deposits observed in the distribution system. The study culminated with the proposal of solutions, both for the prevention of the further accumulation of the deposits and the removal of deposits that are already in the system. To assess the nature and extent of the problem and to focus cleaning efforts to areas of need, the following investigative efforts were undertaken: review maintenance job sheets and customer complaints to track the presence of deposits by location; analyze the chemical composition of the deposits; view water meters removed from service to gain an understanding of how the deposits are formed; removal of sections of water main from the system; review of historical hydro use to assess the impacts of the material deposits in terms of system operating costs. Once it was confirmed that the composition of the deposits was dominated by aluminum, additional investigative efforts were pursued: generate aluminum solubility curves using the source water for the water supplier; jar testing with different combinations of coagulant type, coagulant dose, and pH; monitor plant operations and the distribution system as part of an intensive 10 week enhanced monitoring program for aluminum residuals and related parameters; and, pilot testing of direct filtration and conventional treatment as part of a 2 month side-by-side trial. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

01/01/2001

Number of Pages:

16

File Size:

1 file , 1.1 MB