Facing increased regulations, tight budgets and many long water mains covering miles of geography, Consolidated Water Services (CWS) in Centralia, Ill., had been looking for new ways to increase its operating efficiency. What’s more, the company faced a constant struggle with maintaining chlorine residuals and other water quality issues, primarily flushing dead-end water mains.
However, it was the task of water main flushing that occupied most of the working hours for the seven employees of CWS.
“Flushing, especially early in the year, was taking my employees away from other, more productive tasks” said Jason Green, owner of CWS.
The older parts of the water system managed by CWS served several rural locations around southern Illinois where chlorine residuals and manganese issues were a constant headache.
Additionally in areas of new construction, rapid growth required the installation of long water mains, which ultimately serve very few customers. These long mains, in particular, had a tendency to lose chlorine residuals due to low demand.
In some cases, CWS employees found themselves spending two straight days each spring flushing each one of these troublesome dead-end long water mains in order to boost the residuals from near zero to 2 ppm. This process prevented the completion of other tasks and caused great strain on the pumps and tanks within the CWS water system.
However, the long hours put in by CWS employees revealed that residual levels would usually stay high until the following spring.
But there were other drawbacks in addition to the long man-hours demanded by the flushing process. The process was expensive due to travel time and actual time spent flushing, not to mention wear and tear on vehicles and pumps.
“Our old way of flushing during daytime hours would sometimes run our tanks so low that the alarms would sound. We really preferred to flush at night but we didn’t have the manpower” said Green.
Because flushing was being conducted during daytime hours, customers complained of water waste and in some cases loss of water pressure. Flushing also caused customers to experience some discolored water.
Technological solution
Early in 2003, CWS placed five 9700 automatic hydrant-flushers manufactured by the Kupferle Co., at strategic points on the outskirts of the CWS water distribution system. These automatic flushers incorporated by CWS into the water system installed instantly to a male 21?2-in. NST connection and offered a wide range of flushing parameters.
“CWS wanted a simple controller that would give the benefits of true flexibility and reliability,” explained Rick Russell, a sales manager Kupferle Co.
Additionally, the valve and controller for the automatic flushing system were located inside the aluminum, epoxy coated and lockable box as an extra measure against the elements and for security reasons.
During the operation process, water flows into the flusher and out of a perforated bottom. Another activation sequence involves manually attaching a hose or pipe on the discharge is desired one portion of the perforated bottom can be removed, gaining access to a female 2-in. IP connection.
Additionally, water flow can be controlled to obtain the proper velocity needed for the size of the pipe and to control upstream pressure loss. Options were available to provide a sampling bibb inside the box, adding dechlorination tablets within the box and metering the water flushed as well.
Because the flushers were portable, CWS’s plan was to place the devices on five dead-ends at a time, moving them around until springtime flushing was accomplished and then leaving them on the trouble spots until winter.
For the long mains managed by CWS, the devices were set to flush each morning at 2 a.m. for one hour. Tests were made periodically until residuals reached 2 ppm and then the device was moved.
“We found our flushers needed to
be at the long dead-ends for about eight days, flushing for two hours each
night, to gain the residuals we needed,”
said Green.
Flushing in the early morning hours, when demand was low, greatly eased the strain on the pumps. In addition, the flushing was inconspicuous to customers and also allowed sediment to settle before customers woke for the day.
CWS also found that the automatic flushing program made all other flushing done later upstream much faster. The time required to flush to obtain water clarity and chlorine residuals was greatly reduced. Another bonus was the greater confidence in all bacteriological sampling done within the systems due to increased disinfectant levels.
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