To Automate where No Plant Has Automated Before: Acid Washing of Packed-Tower Chemical Scrubbers

Abstract

The Orange County Sanitation District (Sanitation District), under a capital improvement project, developed an automated procedure to perform acid washing on packed tower chemical scrubbers. Packed-tower chemical scrubbers operate with an alkaline solution, composed of sodium hydroxide, an oxidant, and make-up water. The make-up water may be chlorinated secondary treated wastewater or city water, which are both hard water sources and contribute to scale build up on the random pack media in the chemical scrubbers. In addition, the use of sodium hydroxide contributes to scaling on the packed media. Acid washing is necessary to maintain optimum performance within the chemical scrubber.