Since its construction in 1977, the Stockton East Water District Dr. Joe Waidhofer Water Treatment Plant in Stockton, California, has used two Fischer & Porter model 70C4500 series gas chlorinators with 71P1100A pressure reducing valves for water disinfection. For more than 29 years, the equipment provided reliable and efficient disinfection for the 290,000 plus residents of the Stockton area, located 80 miles due east of San Francisco.
In 1997, the district began investigating replacing the system with new, state-of-the-art gas chlorination equipment. However, budget constraints prevented the district from purchasing new equipment until 2005. At that time, Richard Bermudez, operations supervisor, worked with Ward Technical Products, Inc. to investigate ways of meeting the
Uniform Fire Code (UFC) while keeping gas chlorination equipment as their primary disinfection treatment. The UFC requires that a total containment treatment system be available for emergency use when using gas chlorination.
Dry vs. Wet Scrubbers
The most common scrubber systems used by municipalities are wet scrubbers. Such systems have a lower initial first cost and can easily be fabricated of corrosion-resistant materials. However, dry scrubbers are increasingly being placed in municipal water systems across the country. While these systems are typically more expensive than wet systems, the full long-term investment of dry versus wet scrubbers is not always understood. The cost of the dry system media should be compared to the practical cost of the alternative wet caustic soda solution and related maintenance.