Empowering municipal wastewater treatment: Enhancing particulate organic carbon removal via chemical advanced primary treatment

Abstract

The present study aimed to determine the physical and chemical parameters in the primary treatment process of municipal wastewater by flocculation processes using natural and synthetic polymers as chemically advanced primary treatment (CAPT). Flocculants like chitosan-based, starch-based, and polyacrylamide were chosen, and their feasibility for preliminary treated (PSTin) and pre-treated WASTEWATER (PSTout) underwent precise investigations applying the batch test setup. Since TSS concentration varies hourly in wastewater treatment plants (WWTP) and significantly affects the required dosage of the flocculants, various samples with TSS concentrations ranging from extremely low (<100 mg L−1) to incredibly high (> 700 mg L−1) were gathered to account for all TSS ranges. Several tests were then performed on the samples to establish the efficacy, optimum dosage, settleability, and filterability of the flocs generated by the polymers. The flocs' morphological characteristics were also analyzed by two-dimensional image analysis (2D-IA). The results showed that PSTin or PSTout can be purified solely with synthetic and environmentally confirmed natural-based polymers readily and efficiently. This concept introduces one-stage flocculation for the primary treatment of municipal wastewater rather than the conventional two stages of coagulation-flocculation, which has been used so far while applying harmful aluminum or ferric salts. The results also revealed that the CAPT system can be enhanced by coupling with a microstrain (MS) to remove nearly all particulate organic carbon in the form of COD or TSS. Exploring a range of biological treatment options in conjunction with the CAPT system revealed a significant reduction in external energy reliance for municipal WWTPs, transferring from roughly 75 % to complete independence. This evolution also enables the efficient production of valuable byproducts such as Hydrogen, Polyhydroxyalkanoates, and Ammonium chloride fertilizers, ultimately empowering municipal WWTPs from energy-dependent facilities into self-sustaining energy sources.