PASIG RIVER WATER PURIFICATION BY ULTRAFILTRATION: APPLICATION OF DUAL COAGULATION AND ADSORPTION FOR ENHANCED TREATMENT PROCESS

The treatment of the Pasig River water using ultrafiltration is a promising solution that may help address issues on public water quality and availability around Metro Manila, Philippines. To improve the treatment performance, ultrafiltration can be applied with coagulation and adsorption. In this study, the effectiveness of ultrafiltration in treating the Pasig River water with dual coagulation and adsorption was investigated by determining the percent removal of TDS, turbidity, Escherichia coli (E. coli), nitrate, pH, copper, chromium, lead, total hardness, true color, and odor. The jar test results show that a dual coagulant mixture of 30% organic polyDADMAC solution and 70% inorganic Aluminum Chlorohydrate (ACH) solution, and 10 mL/L was optimal. A 98.01% turbidity removal was achieved under these conditions, and it was able to remove E.coli. Ultrafiltration using the hollow-fiber membrane has an optimum transmembrane pressure of 19 psig; this stage has effectively treated the river water with percent removals of 74.67%, 17.60%, 28.94%, 36.13%, and 50.00% for turbidity, TDS, nitrates, hardness, and true color, respectively. Coagulation and chemical cleaning before operation also substantially increased its ability to filter quicker. Further, adsorption using Granular Activated Carbon (GAC) was proven to be a good post-treatment, reducing the water quality parameters at removals of 19.98%, 11.37%, and 34.07% removal for TDS, nitrates, and hardness, accordingly; the odor also was removed after the GAC adsorption. This study also found that the Pasig River water contains very low concentrations of copper, chromium, and lead, all maintained throughout the water treatment process.