Calcium-Hypochlorite System Reduces Costs, Improves Safety

After dealing with ongoing issues from its 10-year-old chlorine gas system, Chandler Heights Citrus and Irrigation District switched to the Accu-Tab® tablet chlorination system from PPG Industries to reduce costs, improve safety and minimize maintenance and liability.

Located about 30 miles southeast of Phoenix, the Chandler Heights system was originally designed for irrigating citrus groves. Today, it serves 786 residential connections and a few remaining citrus operations over a two-square-mile area. Three wells feed into two tanks, with multiple chlorine injection points. Average treatment rate is 1 mgd, with a peak rate of 1.3 mgd.

Gene Rose, project manager for E2 Consulting Engineers, checks out the Accu-Tab PowerPro® FM3150 system.

“We had continuous problems with the gas injector filter clogging, and we also had to rebuild the gas regulator about every six months at a cost of $728 just for parts,” said Gene Rose, project manager for E2 Consulting Engineers, which designs and manages operations for the Chandler Heights system. “We were also facing higher gas transportation costs, and safe storage and operation was an ongoing concern.”

E2 began evaluating alternative systems, looking at liquid bleach and the Accu-Tab calcium hypochlorite system. After determining that a liquid bleach system had increased safety and environmental regulations and larger storage requirements, E2 selected the Accu-Tab PowerPro® FM3150 system.

“We liked the Accu-Tab system’s operating simplicity and safety,” said Rose. “It also costs less to operate and maintain, and we can use a Level II certified operator to save about $5 an hour in labor costs. In addition, we could install the system ourselves to further reduce costs.”

The NSF-listed Accu-Tab system combines a simple, patented chlorinator with slow-release calcium hypochlorite tablets to provide consistent and controllable chlorine dosages regardless of size and demand. The Accu-Tab PowerPro® FM3150 system includes all components necessary for a turnkey chlorination system and is adaptable for automatic control and multi-point injection.

The three-inch Accu-Tab SI (scale inhibitor) calcium hypochlorite tablets, also NSF-listed, are specifically formulated to help prevent scale formation inside the chlorination chamber, especially in hard-water areas. The tablets are pressed rather than formed, ensuring their physical integrity and eliminating brittleness and extensive breakage.

Chandler Heights’ upgraded system, which included a new piping system, redesigned flow for improved efficiency and the Accu-Tab system, came online in late March 2005. Early results include chlorine residuals of 0.70 mg/l and a system pH of 7.3.