Evaluation of the\nSafe Water Optimization Tool to\nProvide Evidence-Based Chlorination Targets in Surface Waters: Lessons\nfrom a Refugee Setting in Uganda

The Safe Water Optimization Tool (SWOT) generates evidence-based\npoint-of-distribution free residual chlorine (FRC) targets to adjust\nchlorine dosing by operators and ensure water quality at point-of-consumption.\nTo investigate SWOT effectiveness in surface waters, we conducted\ntwo before-and-after mixed-method evaluations in a Uganda refugee\nsettlement served by piped and trucked surface water systems. We surveyed\n888 users on water knowledge, attitudes, and practices; collected\n2768 water samples to evaluate FRC,Escherichia coli, and disinfection by-products (DBPs) concentrations; and conducted\nnine key-informant interviews with system operators about SWOT implementation.\nAfter baseline data collection, SWOT chlorination targets were generated,\nincreasing point-of-distribution FRC targets from 0.2 to 0.7–0.8\nmg/L and from 0.3 to 0.9 mg/L for piped and trucked systems, respectively.\nAt endline, household point-of-consumption FRC ≥ 0.2 mg/L increased\nfrom 23 to 35% and from 8 to 42% in the two systems. With these increases,\nwe did not observe increased chlorinated water rejection or DBPs concentrations\nexceeding international guidelines. Informants reported that SWOT\nimplementation increased knowledge and capacity and improved operations.\nOverall, SWOT-generated chlorination targets increased chlorine dosage,\nwhich improved household water quality in surface waters although\nless than previously documented with groundwater sources. Additional\noperator support on prechlorination water treatment processes is needed\nto ensure maximally effective SWOT implementation for surface water\nsources.