BACKGROUND INFORMATION SHEET - PLAN FOR CHLORINATION/FLUSHING
Prior to 1982 the City of Coffeyville used free chlorination as disinfectant in the drinking water.
EPA determined that free chlorine combines with suspended particles to produce undesirable trihalomethanes (THMs).
By addition of ammonia, the chlorine and ammonia react to produce chloramines in place of the free chlorine. Chloramines do not combine with suspended particles to produce THMs. However, chloramines are not as effective as free chlorine for disinfection, and do not last as long in the system. In addition, any remaining ammonia which does not combine with chlorine to produce chloramines serves as a nutrient (food) for bacterial growth in the water lines, especially lines that do not have sufficient usage for their size to move the water through before the chloramines dissipate (are all used up). This is especially true for dead end lines. Then the bacteria in the lines deplete any chlorine or chloramines brought into the lines.
The Kansas Department of Health & Environment (KDHE) and the City’s water system consultants have recommended eliminating the addition of ammonia and disinfecting with free chlorine for a period of approximately two weeks in combination with hydrant flushing to attempt to remove the slime growth and bacterial after growth in the distribution system. This free-chlorination and flushing program was recommended to be performed on a bi-annual basis (once every two years), or more often if possible.
The free chlorine is a much stronger disinfectant and will kill much of the existing growth. The flushing will move the free chlorine into the lines where it is needed, as well as scouring the lines, breaking up the accumulated sediment/growth and moving it out of the lines.
However, breaking loose the accumulated sediment may give the water an unpleasant taste and odor (sulfur), and a murky appearance in some areas of the City. In some areas with iron lines the water may also have a reddish appearance. The effects are similar to those due to high use from a large water leak or the Fire Department drawing water from hydrants to fight a fire.
Although the chlorine concentration will be the same as before, and will not exceed KDHE regulations, the water may also have a stronger odor of chlorine (similar to a swimming pool). The odor is caused by the reaction of chlorine with the bacterial accumulation. Under our normal operation, ammonia combining with chlorine to form chloramines removes the chlorine odor, but chloramines are not as effective for disinfection at the same chlorine concentration.
Although the appearance, taste, and odor may be unpleasant, the water will continue to meet the requirements of KDHE for safe drinking water.
The following is information to assist you if you receive any calls during the project.
Main items to point out are:
< KDHE recommended the chemical modifications (eliminating ammonia use) and system flushing.
< The chlorine concentration is no higher than before, the elimination of ammonia just makes the chlorine smell stronger.
< The water will continue to meet requirements of KDHE throughout the project or KDHE
would not have recommended, or allowed, the project.
< The inconveniences are short term in any given area (possibly 1 week).
< The areas receiving the worst effects are the areas receiving the most benefit because they
have the most build-up being removed.
< The inconveniences are necessary in order to achieve the long term benefits of safe drinking
water and continued compliance with KDHE regulations.