Groundwater Quality in the Endemic Areas of Chronic Kidney Disease of Unknown Etiology in Sri Lanka and Its Treatment by Community-Based Reverse Osmosis Water Treatment Plants

Community-based reverse osmosis (RO) water treatment plants provide an interim solution for producing safe drinking water for the endemic areas of chronic kidney disease of unknown etiology (CKDu) in the rural dry zone of Sri Lanka. RO-treated groundwater diminishes the progression of CKDu; thus, proper maintenance of these RO plants is indispensable to protect public health. We investigated the quality characteristics of groundwater in the endemic areas of CKDu; the performance, operations, and maintenance (O&M) of the existing RO plants; and the socioeconomic background of the RO plants. We analyzed feedwater (i.e., groundwater) and treated water from 32 RO plants in Anuradhapura District, comprising 27 in the CKDu high-risk (HR) region and five in the low-risk (LR) region, to establish the major chemical and biological water quality parameters. The alkalinity, hardness, and microbiological parameters in groundwater exceeded the maximum allowable levels (MALs) for drinking in all the study areas. Additionally, the total dissolved solids (TDS) and magnesium exceeded the MALs exclusively in the HR areas. The quality and the chemical composition of groundwater did not indicate significant seasonal differences. The elevated occurrence of magnesium-predominant hardness and ionicity in groundwater showed a significant relationship with the incidence of CKDu. All the RO plants achieved high removal rates (> 90%) for excessive chemical constituents in groundwater, but the recovery rates were slightly low (~ 46%). The current disinfection practices in the RO plants were insufficient to ensure the microbial safety of the product water. The low demand for product water, scarcity of groundwater, lack of technical capacity of the local communities, poor maintenance practices, and unplanned brine removal were the key issues concerning RO plant O&M. Unless properly handled, the lack of rules and regulations for RO water treatment in the CKDu-endemic region could lead to numerous environmental and public health issues in the future.