Assessment of drinking water quality for raw water and treated water at Kangar, Perlis, Malaysia

Abstract

Clean and safe water is vital for human health, whether it is used for drinking purpose, food production or domestic use. The aims of study are to investigate raw water quality parameters and analysed Water Quality Index (WQI) at Timah Tasoh Dam. The research also analyses the treated water quality parameters at Timah Tasoh Water Treatment Plant, Kampung Belukar, Kampung Kechor and Taman Bukit Kaya, then compared to National Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO) guidelines. The raw water was analysed for pH, total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO) and ammoniacal nitrogen (AN). Treated water was analysed for copper (Cu), iron (Fe) and nickel (Ni). Timah Tasoh Dam is categorized as slightly polluted where its WQI index was 76.94. Sources of pollution related to non-point sources such as fishery activities, agricultural and livestock wastes, and domestic wastes. For treated water parameters, significant results showed at Taman Bukit Kaya which recorded the highest concentrations of Cu, Fe and Ni, at 1.24 mg/L, 0.76 mg/L and 0.01 mg/L respectively. The reason is that Taman Bukit Kaya is the furthest distance from Timah Tasoh Water Treatment Plant, thus the residence time of water in pipe is longer which results in higher concentration of heavy metals. Concentration of Cu and Ni was complied with the guideline values of WHO and only Ni was complied with NSDWQ. Based on the result of treated water analysis at Kangar, Perlis, the drinking water quality is considered as safe for drinking.