Evaluation of water quality of community managed water supply schemes in southern province

Abstract

Water is a crucial element that covers two-thirds of the surface area of the earth, and it is one of the main substances in the body of every living being on the earth. Thus clean, safe, and adequate freshwater is important for secure good health. The National Water Supply and Drainage Board (NWS&DB) is the main responsible institution for providing safe drinking water within Sri Lanka. However, NWS&DB is unable to provide safe water to the country’s entire population. Therefore, Community Managed Water Supply Schemes (CMWSS) were implemented as a solution for the existing water scarcity issues in rural areas of Sri Lanka. It was revealed that most of the CMWSS in Southern Sri Lanka are supplying raw water without proper treatment. So continuous monitoring, management, and evaluation of water quality in these schemes are essential to supply safe potable water. There are 172 CMWSS in the Galle district, and 10,814 families benefit from those schemes. On the other hand, there are 333 schemes in the Matara district, and 26482 families benefit from these CMWSS. In Hambanthota district, there are 182 CMWSS to provide drinking water for 38157 families. In this study, the water quality of selected CMWSS (71% out of total schemes) in the southern province of Sri Lanka was assessed by applying the Canadian Council Minister of Environment Water Quality Index (CCMEWQI). Altogether, water quality (WQ) of 488 (Galle 172, Matara 172, Hambanthota 144) CMWSS was evaluated under the 14 parameters such as temperature, turbidity, pH, electrical conductivity, total hardness, nitrate, iron, fluoride, E. coli, total coliforms, Mn, Pb, As and Cd, using Standards method of American Public Health Association and compared with the Sri Lankan Standards for drinking water (SLS 614 2013). Water Quality Index (WQI) was also developed for each source and rated as Excellent, Good, Medium, Bad, and Very Bad. Developed WQI revealed that none of the CMWSS in the southern province categorized as “Very Bad” quality (0-25). Among 488 schemes in the province, only (2.3%) 11 schemes belonged to the “Excellent” category (91100) based on this WQI. Majority of the schemes (39.1%) had the WQI between 26-50 and

rated

as “Bad” and need to have secondary treatment. There were 33.8% of CMWSS that belonged to the “Medium” category (51-74) of WQI and 24.8% in the “Good” category (7590)

which were not suitable for drinking without preliminary treatment. More than half (56.3%) of CMWSS in Hambanthota district were in the ‘Bad’ category. Therefore, Hambanthota district CMWSS were highly contaminated than those in Galle and Matara districts. It was noted that raw water of (97.7%) 477 CMWSS in the southern province need to be further treated for E. coli, total coliforms, conductivity, hardness, iron, fluoride, pH, and turbidity. The questionnaire survey revealed, that 62.6% of consumers used water without any treatment. It is recommended to educate consumers of CMWSS on basic household treatment systems so that they can treat the water before consumption. It is also required to introduce more cost-effective treatment procedures for the consumers as the majority of the household in the southern province monthly income is less than Rs.25,000.