Efficacy of an appropriate point-of-use water treatment intervention for low-income communities in India utilizing Moringa oleifera, sari-cloth filtration and solar UV disinfection

Abstract

This study investigated the efficacy of a POU water treatment system featuring sari-cloth filtration and/ or Moringa oleifera coagulation as pre-treatments for solar disinfection (SODIS). Surface water from a peri-urban slum in Chennai, India, was treated and analysed for turbidity, organic content via chemical oxygen demand (COD) and microbiological quality via most probable number (MPN) enumeration of total coliforms. Pre-treatment with both moringa coagulation and sari-cloth filtration significantly improved the turbidity of raw water compared to no pre-treatment controls (P ¼ 0.0002). Optimal moringa coagulation did not outperform sari-cloth filtration (P ¼ 0.06), but combining optimal moringa coagulation with sari-cloth filtration significantly outperformed either pre-treatment independently with respect to turbidity (P ¼ 0.016 and P ¼ 0.0001, respectively). The addition of moringa was found to increase COD in treated water, with greater doses of moringa resulting in higher COD levels (P ¼ 0.04). Increased organics may have encouraged the re-growth of coliform bacteria that was observed in those jars receiving moringa coagulant such that, with respect to MPN, those jars which were subject to optimal moringa coagulation did not outperform those undergoing sari-cloth filtration alone (P ¼ 0.41). Sari-cloth filtration is recommended as a pre-treatment for SODIS whereas moringa is not, as further investigation on the relationship between organics and bacterial re-growth is necessary.