Replacement Of Gas Chlorination System: City Takes Advantage Of Special NaOCl Dosing Unit For Reliability And Cost-Effectiveness

By Cliff Lebowitz

Operations management for a municipal direct water filtration plant reports achievement of a reliable and cost-effective change in chlorination systems that has continued to provide for effective disinfection, while better meeting safety and efficiency criteria.

The plant has a treatment capacity of about 150 MGD. Average flow is about 50 MGD. For chlorination, the plant previously relied on three chlorinators capable of feeding 2000 lb. of chlorine each, 24/7, with typically 12 chlorine cylinder tanks delivered every two weeks, and 18 cylinders on site at a time.

In 2006, they switched to a special, vacuum-driven sodium hypochlorite (NaOCl) delivery system that includes four 11,000 gal. tanks for storage. The bulk-purchased NaOCl is delivered by 4500-gal. tanker truck, and six patented, metered feeders provide a total of 1300 gal./day for their treatment train, via 9 different application points.