Assessment of Quality of Water from Catchment to Consumers: A Study based on Rahas-Ella Water Purification Plant in Kandy, Sri Lanka

Introduction: Rahas-Ella is one of the fascinating waterfalls located in the Wattegama area in Kandy District, Sri Lanka. By receiving raw water from Rahas-Ella, a water purification plant was established in 2013 to provide safe drinking water to the residents in Wattegama municipal area. An investigation was conducted to evaluate several water quality parameters for both raw and purified water, in response to consumer complaints over the quality of drinking water received from this purification plant.

Methodology: Thirteen sampling locations (L01-L13) were identified along the waterfall, from the onsite water purification plant, two wells, and in addition two tap water sources through which the purified water is distributed. Some selected physicochemical and bacteriological parameters were analyzed.

Results: The study revealed that several parameters were higher than the standards concerned for drinking water. Mainly, the turbidity level was high in both the catchment and the intake and this could be a serious health risk to the community. Further, considerably high total counts of both coliforms and Escherichia coli (E. coli) were detected in all samples exceeding the standard values. Although oil and grease were not monitored in this present study, several dwellers reported problems associated with oil pollution.

Conclusion: Based on the observations and results of the study, numerous measures were recommended to improve the water quality of the catchment and to upgrade the treatment facility. The relevant authorities must understand the pathways of microbiological and physicochemical contamination of drinking water and their potential health implications and should carry out necessary steps to improve the quality of water distributed from this purification plant and lessen the negative consequences of improperly purified water on human health.