Chlorine Gas Decision Tool

The Chlorine Gas Decision Tool (March 2006) provides water and wastewater utilities with the means to conduct a simple assessment of alternatives to chlorine gas disinfection. The U.S. Department of Homeland Security’s (DHS) Science and Technology Directorate, Advanced Research Projects Agency contracted with the National Association of Clean Water Agencies (NACWA) to develop the tool in an effort to encourage water and wastewater utilities currently using chlorine gas for disinfection to consider alternatives. 

Wastewater and drinking water utilities have safely and effectively used gaseous chlorine and sulfur dioxide for disinfection and wastewater dechlorination respectively for decades. While various regulatory programs have placed numerous restrictions on the uses of these chemicals, recent focus on the possibility of a terrorist attack at a wastewater or drinking water facility, has underscored the potential hazard these chemicals present. If released into the atmosphere, chlorine and sulfur dioxide have the potential to pose a hazard for utility employees and the public surrounding the affected facilities. This Chlorine Gas Decision Tool (Tool) was developed to assist wastewater and drinking water utilities who wish to evaluate alternative methods for disinfection.

Wastewater and drinking water utility managers considering alternatives to gaseous chlorine can use the Tool to compare the advantages, disadvantages and costs of each alternative, with the goal of determining which option best meets their particular utility’s needs. Cost criteria including capital costs, operations and maintenance (O&M) costs, and life cycle costs for the alternatives are evaluated by the Tool. Also included are comparisons of the non-monetary factors critical to the evaluation and selection of a disinfection technology. These non-monetary factors are used by the Tool to perform a benefit to cost analysis.