Deadline: 22-Oct-2025
The Water Research Foundation (WRF) is seeking proposals for a research project to evaluate measurement techniques for disinfectant residuals and develop standardized response procedures for low-residual events in water distribution systems.
The project has a budget of up to $300,000 and an anticipated performance period of 18 to 24 months. The research approach includes evaluation of measurement techniques, specifically identifying commonly used field measurement techniques for chlorine and chloramine residuals (e.g., N,N-diethyl-p-phenylenediamine (DPD) colorimetric method, iodometric methods) and assessing their suitability for monitoring low residuals down to 0.2 mg/L or lower (e.g., accuracy, speed, ease of use, quality control requirements); conducting controlled laboratory experiments to test the accuracy and precision of each method at various low residual levels (e.g., 0.22 mg/L to 1.0 mg/L) under field conditions at a range of water quality conditions (e.g., temperature, total organic carbon, alkalinity, and pH); describing interferences and positive biases; and analyzing the reliability of methods in detecting and quantifying low disinfectant residuals down to 0.2 mg/L or lower, including how different chloramine species affect measurement accuracy and compliance.
The project also includes development of response procedures for low residuals, such as gathering feedback from utilities—representing a variety of system sizes and geographic locations—on current practices for responding to low residuals (e.g., flushing, booster stations), assessing alternative disinfectant boosting methods (e.g., localized re-chloramination, mixing strategies), identifying common causes of residual loss (e.g., organic matter, bacterial regrowth, temperature, pH shifts, iron corrosion) and developing methods or strategies to diagnose and resolve likely causes, including the identification of associated risks, competing priorities, and potential unintended consequences, recommending best practices for mitigating low residuals, including immediate actions (e.g., increase in disinfectant feed, flushing, reservoir cycling) and long-term strategies (e.g., conversion from chlorine to chloramines, installation of disinfectant booster stations, other infrastructure upgrades, eliminating dead ends, and main replacements), and providing guidance on maintaining stable residuals in blended disinfectant systems, while addressing risks, competing operational priorities, and possible unintended consequences of mitigation strategies, and developing a standardized low-residual investigation protocol with step-by-step guidance on sampling, data analysis, water quality review, and regulatory documentation, including field-ready checklists, decision trees, and/or an options list to assist operators in selecting appropriate response actions based on site-specific conditions.
Finally, the research approach includes development of a final report and guidance materials, which consists of delivering a final report with detailed information, a literature review, case studies, and recommendations, developing a set of actionable recommendations for water utilities to improve their residual monitoring, response procedures, and mitigation strategies, and creating field manuals, quick reference guides, training videos, and/or troubleshooting charts to assist operators in decision-making.
The project is seeking proposals from entities both in and outside the U.S., with a flexible approach to deliverables. Suggested deliverables include research reports, field manuals, quick reference guides, troubleshooting charts, webcasts, and conference presentations. Proposers are encouraged to be creative and original in their submissions.
The evaluation of proposals will be based on several criteria, including understanding of the problem, technical and scientific merit, qualifications and capabilities, communication plans, and budget. Researchers who are late on ongoing WRF-sponsored studies are not eligible to participate. The proposal submission deadline is October 22, 2025, at 3:00 pm Mountain Time.
For more information, visit WRF.
