Water conservation study with the installation of new sand filters in the cooling water return: Innovation analysis and improvement of cooling water performance

The installation of sand filters in cooling water systems is essential to maintain optimum performance and minimise maintenance downtime. Sand filters are commonly used in cooling towers to remove suspended solids, algae and other particles that can clog the system and reduce efficiency. The benefits of sand filters in cooling water systems include reducing fouling in the cooling water stream, where sand filters significantly reduce fouling of heat exchangers and other components in the cooling system, helping to reduce operating costs and downtime. The importance of cooling water treatment with sand filters is to improve water quality. Sand filters can remove total suspended solids (TSS), reduce conductivity, chemical oxygen demand (COD), biochemical oxygen demand (BOD) and turbidity. The purpose of this study was to investigate the performance of installing a sand filter in the cooling water return line to reduce the amount of effluent due to high levels of contaminants in the cooling water and also to reduce the use of fresh water. TSS dropped from 1200 mg/L to 350 mg/L, conductivity from 1700 µS/cm to 700 µS/cm, COD from 230 mg/L to 150 mg/L, BOD from 35 mg/L to 15.6 mg/L and turbidity from 5.6 NTU to 3.2 NTU after the sand filter was installed. After the sand filter was installed, the recirculation rate increased by approximately 16.5%, the blowdown rate decreased by approximately 24%, the evaporation rate decreased by approximately 20.5% and the water make-up decreased by approximately 14.2%.