Case Study: Gas Scrubber Effluent Scaling Problem

Effluent from a scrubber on the process gas stream, which had an average flow rate of 35 gpm, contained high water hardness (460 ppm) and alkalinity (300 ppm) and was orginally allowed to be direct discharged to the city without any treatment. In early 2007, the city directed the client that they now had to adjust the pH of the effluent stream to between 8 - 8.5.

Two issues developed as a result:

1) The amount of 50% sodium hydroxide required to maintain the required effluent pH increased dramatically to approximately 170 gpd.

2) Adjusting the pH caused a sever scaling issue that required routine cleaning of the piping in the facility as well as the line leading to the city system.