Split treatment evaluation, optimization, and operation of the Ames water treatment plant

The City of Ames Water Treatment Plant underwent a water treatment and optimization study because of Force Majeure declarations from their supplier of carbon dioxide due to the coronavirus pandemic of 2019. The Force Majeure declaration received by the City of Ames in March 2020, stated that the contracted supplier could guarantee only 50% of the contracted amount of carbon dioxide and added a sixty dollar per ton surcharge. The uncertainty of carbon dioxide availability and increased cost created a need to evaluate alternative treatment technologies. After consulting with professors from Iowa State University and other industry experts, the Ames Water Treatment Plant decided to pursue a split treatment trial. Split treatment is advantageous, because it reduces the demand for carbon dioxide needed for pH adjustment while still producing a high-quality product. Split treatment is implemented when a facility bypasses a portion of their influent raw water from the typical treatment process. This bypassed water is added back to the lime softened water at later stages. When the bypassed water encounters the lime softened effluent, it effectively reduces the pH, thus requiring less carbon dioxide for final pH adjustment. Prior to this trial the Ames Water Treatment plant obtained approval from the Iowa Department of Natural Resources to pursue the use of this treatment technology. During this trial, the Ames Water Treatment plant found split treatment to be a viable method to reduce carbon dioxide demand for their treated product water.