Development of Strip-Based Water Quality Test Kits for Assessment of Free Residual Chlorine (FRC) with Sensitivity up to 0.1 ppm for Field-Level Applications

Background & Description: Free Residual Chlorine (FRC) is a critical indicator for ensuring the microbiological safety of drinking water in supply systems. Routine monitoring of FRC is essential to verify the effectiveness of disinfection processes and to prevent the distribution of unsafe water to consumers. Further, many commercially available kits use o-toluidine (OT) as a reagent, which has been banned by the Bureau of Indian Standards (BIS) due to environmental concerns, while alternative reagents such as N, N-diethyl-p-phenylenediamine (DPD), though safer, are relatively expensive. These limitations highlight the need for a cost-effective, user-friendly,and reagent-free or low-reagent portable solution for reliable FRC monitoring in field conditions. There is a need for a simple, accurate, and low-cost strip-based test kit capable of measuring FRC concentrations with a sensitivity of up to 0.1 ppm. The solution should provide rapid and easy-to-interpret results and be suitable for use by village-level workers, community volunteers, and water supply functionaries. The proposed solution should: Accurately measure FRC up to 0.1 ppm sensitivity. Provide quick and easy field-based testing. Be affordable and suitable for large-scale deployment. Require minimal training and no specialized equipment. Support digital recording and reporting of results.

Expected Outcomes

1. Development of indigenous, strip-based Free Residual Chlorine (FRC) test kits with high sensitivity and accuracy. 2. Strengthening of field-level monitoring mechanisms for effective chlorination in drinking water systems. 3. The detection range of the test kits should be aligned with prescribed drinking water quality standards (BIS 10500). 4. Promotion of enhanced community participation in water quality surveillance and monitoring. 5. Provision of a cost-effective and scalable solution for routine water quality monitoring in rural areas.