Municipal Water Treatment
Weighing tanks of chlorine and polyphosphate for drinking water treatment
The Monona Water Utility in the city of Monona, Wisconsin was looking for a better way to monitor its rural well sites.
At each site, chlorine was being used to disinfect the water supply while polyphosphate was also being added to control pH in order to improve the effectiveness of the chlorine. The current process required frequent visits by water utility personnel to insure the accuracy of the chlorination process and a consistent level of disinfectant in the drinking water supply.
According to Bob Jacobs, the lead operator of the water utility, “The problem was two-fold – one, the sites were unmanned and two, because of low usage, they only needed to be visited every three to four weeks to load a new container. This meant trips had to be made several times a week to each well site to monitor the chemical feeding and ensure proper dosing of the water supply.”
The goal was to improve operational efficiency and reduce labor costs associated with monitoring the chemicals. In addition, they wanted to improve the accuracy of the chlorination and pH control processes by taking advantage of newer digital technologies that would allow remote monitoring from the central office.
Scaletron’s local distributor CTW Corporation, met with the water utility to evaluate the current process and determine their requirements. After careful analysis, they recommended Scaletron’s corrosion resistant, digital tank scales as an excellent solution to handle the weighing of the corrosive chemicals. Specifically designed for accurate weighing of corrosive chemicals, the Model 4040 features corrosion resistant construction with rugged steel frame that is zinc oxide primed and dry powder epoxy coated and a solid PVC deck.
To meet the water utilities needs, two 36”x36” Model 4040™ Digital Platform Scales were installed at each well site to weigh 500 lb. polyethylene tanks containing chlorine and polyphosphate. To reduce equipment costs, a single Model 1020-2™ Dual Channel Controller with a 5 digit electronic display is used to control both scales. With a 4-20 mA output as standard, this controller made remote monitoring of chemical usage from their central office via SCADA possible thus eliminating frequent visits to the sites as well as improving the accuracy of the chemical dosing process.
The new Scaletron platform scales enabled the Monona Water Utility to meet its goal of reducing labor costs associated with frequent visits to its well sites by allowing real-time, remote monitoring of the chemical feeding from a central office.
In addition, the new scales gave them greater control over the chlorination process by offering insights on feed rates, consumption, time till empty, etc. on a daily basis that was not practical with unmanned sites.