Deadline: 22-Oct-2025
The Research Project is seeking proposals to help water utilities establish comprehensive programs and practices for maintaining a minimum disinfectant residual throughout the distribution system.
Project Objectives: Review the demonstrated benefits and actions of a disinfectant residual, as well as the negative consequences of carrying a low disinfectant residual in a distribution system. Recommend routine and enhanced monitoring requirements for disinfectant residuals and develop response procedures and plans to subsequently monitor additional water quality parameters when disinfectant residuals are detected at or below the minimum required levels. Examine U.S. Environmental Protection Agency-approved measurement methods and their applications to determine compliance, practical field use, quality control requirements, cost effectiveness, method reporting limits based on instrument type, and accuracy in detecting low disinfectant residuals. Identify mitigation actions for restoring disinfectant residuals in a distribution system, ranging from immediate actions, such as flushing, to capital improvements like main replacement or booster station installation. Provide guidance materials for practical applications and operator training. Determine ongoing research needs for filling information gaps.
This project will: provide insights into the reliable field measurement of disinfectant residuals, offer guidance on responding to low residuals, review online monitoring applications, evaluate the benefits and consequences of maintaining a residual, develop practical strategies to help utilities maintain disinfectant residuals effectively, and identify information gaps that ongoing research can address.
As federal regulators move towards mandating a quantifiable minimum residual, water utilities must establish comprehensive programs to ensure compliance. The U.S. Environmental Protection Agency is considering a regulation that would create new compliance and reporting obligations. To align with these changes, utilities must update monitoring programs and establish standardized response protocols that provide clear and defensible documentation.
Accurate and reliable field measurement methods and sampling techniques are essential for compliance as disinfectant residual testing must be done at the time of sampling. Existing analytical methods have limitations at low residual levels. Utility operators need guidance on best practices for verifying and addressing low disinfectant residuals, as inappropriate field sampling practices can result in inaccurately low measurements. In chloraminated systems, the presence of different chloramine species at low levels may carry significant operational and regulatory implications.
The project aims to provide utilities with clear guidance on how to respond to non-detectable disinfectant residuals, including how to verify low levels, ensure proper and representative sampling, identify relevant water quality measurements, and conduct local investigations. Best practices for responding to low residuals are needed, similar to those established for responding to total coliform positives. For systems using both free chlorine and chloramine, additional challenges such as blending, boosting, and maintaining residual stability must be addressed.
The research approach for this project may include a literature review to assess sampling techniques and regulatory standards, and to identify challenges faced by utilities. It may also involve an evaluation of commonly used field measurement techniques and controlled laboratory experiments to test the accuracy and precision of each method at various low residual levels. Another element of the research approach is the development of response procedures for low residuals, which would involve gathering feedback from utilities and identifying common causes of residual loss to create a standardized investigation protocol.
Applicants for this project may request up to $300,000 in WRF funds. The anticipated period of performance is 18 to 24 months from the contract start date. This project encourages creativity and originality from proposers regarding the nature and scope of deliverables, which may include research reports, field manuals, and quick reference guides. Proposals will be accepted from both U.S.-based and non-U.S.-based entities, including educational institutions, research organizations, governmental agencies, consultants, or other for-profit entities. Researchers who are late on any ongoing WRF-sponsored studies without approved no-cost extensions are not eligible to be named participants in any proposals. Proposals are accepted exclusively online and must be fully submitted before 3:00 pm Mountain Time on Wednesday, October 22, 2025.
For more information, visit WRF.
