AWWA ACE68964

This powerpoint presentation begins by providing a brief overview of the City of Raleigh distribution system, water quality parameters affected by nitrification, the current Total Coliform Rule (TCR), and possible future regulatory compliance. The beginning of coliform studies by CDM in 2004 is presented, along with a water quality monitoring plan, and distribution system field studies. A 2005 CDM distribution system water quality field study is outlined, including sampling plan improvements, TCR sample site plan update, and study completion and summary of changesimplemented. Results achieved include the following:dramatic decline in number of coliform positives; improved communication within the Water Plant Division, and between the Water Plant Division and otherPublic Utilities Divisions using GIS;tracking and trending of laboratory data; and,better prepared when drought hit in 2007-08. Summary of key past and future items thatimprove TCR compliance is presented, including the following:high residual chlorine concentrations;additional monitoring and enhanced operation ofdistribution system to keep tanks turned over anddead-ends flushed and to watch for nitrification;enhanced full-system flushing with elevated amountsof free chlorine flushed though sample sites, deadends; updated TCR Sampling Plan;improved model and identification of isolation zones; developed a Department Operating Procedure forcoliform occurrence investigation and bridgedepartment sharing of relevant information with GIS (spotflushing, main breaks, sample plans, new lines,backflow, plumbing), Response Team formed;expand cross-connection control program, siteplumbing investigations;implement nitrification control procedures (lowerammonia, flushing, etc.); and,corrosion control and infrastructure upgrades andmaintenance. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

37

File Size:

1 file , 2.8 MB