River Bank Filtration: Study of Langat River Water and Borehole Water Quality

Abstract

The characteristics of water sources are important factors that determine the methods of treatments and quality of water distributed to consumers. The quality of Langat River and borehole water were investigated in this study to obtain the baseline water quality for riverbank filtration (RBF) systems. Water samples from Langat River and seven boreholes constructed at different distances from the river bank were collected and analyzed for turbidity, color, BOD 5 , COD, NH 3 -N, E. coli , and heavy metals. Results indicate that the average levels of BOD 5 , COD, and NH 3 -N in the river are 23, 52, and 2 mg/L, respectively. The water is also very turbid with a turbidity value of over 400 NTU. Metals in the river water are not an issue, except for iron (Fe) and arsenic (As) with average levels of 4.92 and 0.073 mg/L, respectively. In addition, the average concentration of the pathogenic bacteria E. coli in the river is also high with a value of 7,500 per 100 mL. The quality of water from boreholes exhibits improvement in terms of turbidity, color, total dissolve solid (TDS), dissolved oxygen (DO), COD, and E. coli . However, the levels of trace elements, such as arsenic (As), are higher in boreholes; the readings reached 0.13 mg/L. The 0presence of manganese (Mn) in wells is likewise high, with readings between 0.35 and 0.95 mg/L. Results indicate that distance is not the main factor in the increase in removal efficiency. Instead, site geology and biogeochemical processes in groundwater are probably the factors that determine pollutant removal and increased As and Mn concentrations in borehole water. Based on the information presented, this study may be able to provide baseline information regarding the suitability of an RBF system for a selected area.