Combined Treatment of Domestic Wastewater using Anaerobic and Solar Photocatalytic Treatment

Abstract

Abstract The present study utilizes anaerobic and solar photocatalytic methods to treat domestic wastewater. For stage I, a granulated hybrid upflow anaerobic sludge blanket reactor (HUASB) with a working volume of 5.9 L was used. It was run in a recirculation mode for 3 days called "one cycle," and 30 cycles were run to find out the stability of the anaerobic treatment. During stage I anaerobic treatment, 90% of the chemical oxygen demand (COD) was removed, and it increased with an increase in digestion period for each cycle. Volatile fatty acids did not cause any operational problems during the stage I anaerobic treatment, being in the range of 280 to 90 mg/L. Stage I treated wastewater was subjected to a stage II solar photocatalytic oxidation method. The optimum pH and catalyst loading for the solar photochemical oxidation were found to be 5 and 200 mg/L, respectively. Stage II, treatment at an optimized condition, removed 66% of organics from the stage I treated wastewater. The combined COD removal due to the combination of these two technologies was found to be 96%.