Case Study for Customer Location CA95:
Reservoir or Lake Use:
This is one of 40 elevated water storage tanks for potable water. The facility plans to convert to chloramine in June 2005.
System Overview and Reservoir:
The system is composed of above ground steel tanks that range from 1 to 4 million gallons (MG), all above 30 ft high. The city’s Water Division (WD) converted to chloramine in June 2005.
Reported Problem Before SolarBee Installation:
During the summer months there was a 7-8° F difference in water temperatures from the top to the bottom of the tanks; during the fall months, temperature differences were 3-4° F. This stratification creates unequal water age in the tanks, and promotes undesirable nitrification in chloraminated systems. Therefore, objectives were to thoroughly mix the water in the tanks to eliminate stratification, short-circuiting and stagnant water conditions, and to provide a uniform 2-3 day water age.
SolarBee Installation:
Date: Dec. 2004, one (1) SB1250v12-PW was installed. April – June 2005, thirty-three (33) SB1250v12-PW units were installed in the other above ground tanks, so now all of the potable water storage tanks in the WD system utilize SolarBees for circulation.
Results:
Testing by the WD demonstrated the SolarBee’s ability to quickly destratify and completely mix water in the tank. When they injected chlorine for boosting in order to maintain a 1 mg/L concentration, testing showed that concentrations of free chlorine in the SolarBee tanks were 0.98 – 1.0 mg/L throughout the tank. Because the tanks are close to the distribution, rapid and complete mixing is essential. Of the various options considered by the WD, some costing over 2 million dollars, none worked as well as the SolarBee. Based on the performance of the unit tested and comparing the SolarBee performance results to the other types of equipment tried in the past, the city purchased 33+ more units in 2005 and 2006. Operator is very pleased with the proven mixing abilities of the SolarBees and more consistent chlorine residuals, which has made their conversion to chloramine much easier.
Potable water tank with SolarBee crew on top.
Update: 05/09/2007
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