The population in Ramanathapuram district of Tamil Nadu State (India) faces potable water scarcity throughout the year in general and acute drinking water problems in lean periods of the year. To mitigate this problem, eleven reverse osmosis (RO) desalination plants were installed in problem villages in the district. General performance of these eleven plants and in-depth evaluation of two plants was undertaken to focus attention on the physico-chemical quality of water at various stages of treatment, present status with respect to operation and management (O & M) financial implications and overall management in a rural situation.
The study indicated that performance of these RO plants was satisfactory in removing high TDS, though the efficiency deteriorated with time. The average utilization of these RO plants since their installation was 46% as compared to the design capacity, mainly due to non-availability of power in rural areas, time lapsed in repairs of pumps, and non-availability of spares. The average capital cost/m3 and O & M cost/m3 of product water from these eleven plants works out to Rs. 27.40 and Rs. 44.50 respectively; when plants are utilized as per the design capacity. These costs are high and not affordable by the rural population. The RO plants were socially acceptable since the population was satisfied with the treated water quality.