February 25, 2010

New water treatment process begins Monday

New water treatment process begins Monday
By STU MERRY

Conversion to a chloramine disinfection method for the city and rural water distribution system will begin Monday.
The goal of the changeover is twofold: The addition of chloramine into the distribution system is an effort to produce a higher quality drinking water, which will meet the EPA’s Stage 1 and Stage 2-disinfectant/disinfection byproducts rule.
The city presently uses chlorine to disinfect raw water that comes from Lake Sakakawea. With the new method, a secondary disinfectant will be added, which is a longer lasting residual and will reduce byproduct in the system.
Will customers notice any difference in taste, smell or color? City officials said the result is not known, but it is expected that the new treatment method should reduce any taste and odor problems that may exist.
The changeover is the third and final stage of a number of capitol improvements to the water system. The changes that have taken place over the past 15 months affect all aspects of the process: Bringing raw water from the lake to the treatment plant; the treatment process; the storage facility, then to the tap.
Improvements have been made to the water intake facility located on the southwest tip of Fort Stevenson State Park. Variable frequency drive (VFD) pumps are being utilized to control the speed to match the rate at which water is produced. The pumps previously used for this purpose could not accept VFD control.
The new pumps with VFD’s at the wet well will provide a constant flow to the water treatment plant. The pumps will slow down or speed up to maintain a constant flow rate and pressure to the plant.
 


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