Assessment of water quality variation: tool for effective water treatment system operations

Abstract

Water quality and treatment systems are dynamic because they constantly undergo seasonal variations in water chemistry, varying plant operating conditions, and new environmental laws, among others. Because of this, proper monitoring is essential to ensure that the water supplied by the treatment system safeguards public health from waterborne diseases. Selected surface water quality parameters as inflow were obtained before treatment against the treated water for different hydrological periods (2009 – 2019) from a water treatment system to determine the trend in water quality variation, water quality index, and effectiveness of the treatment process.  Each hydrologic year had varying concentrations of selected parameters for raw and treated water quality. The concentration values of pH, electrical conductivity, total hardness, calcium and magnesium hardness, chloride, and total dissolved solids of the natural source water were within the recommended limit. Turbidity concentrations were above the recommended value for each hydrologic year, values ranging from 14.65 – 57.98 NTU, and iron concentration was above the permissible for 2010 and 2012. Selected parameters were all within the threshold limit after treatment with a water quality index (WQI) ranging between 1.09 – 39.39, rated as good/excellent water quality. The treatment system operations were effective throughout the observation period. However, turbidity, iron and hardness should be tested more frequently during the operational and verification monitoring process.