Challenges and Overall Performance of an Industrial Wastewater Treatment Plant: A Case Study of Bu-Ali Industrial Town, Hamadan

The present study aimed to investigate and evaluate the performance of the Bu-Ali Industrial Town wastewater treatment plant (WWTP), Hamadan, Iran. In this study, the physicochemical and microbial characteristics and heavy metal contents of influent and effluent were evaluated. The mean values of total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), dissolved oxygen (DO), biological oxygen demand (BOD۵ ), cyanide, total coliform (TC), fecal coliform and pH in influent were ۱۲۱۰ mg/L, ۲۱۶۵.۵ mg/L, ۲۱۸۷.۵ mg/L, ۲.۴ mg/L, ۹۶۷.۵ mg/L, ۲۰.۸ mg/L, ۱.۳×۱۰۱۰ (MPN/۱۰۰ mL), ۱.۲×۱۰۹ (MPN/۱۰۰ mL) and ۶.۷, respectively. Additionally, the mean values of the mentioned parameters in effluent were ۹۴.۵ mg/L, ۲۳۷۰.۴ mg/L, ۲۲۰.۷ mg/L, ۵.۲ mg/L, ۱۱۳.۴ mg/L, ۲.۰ mg/L, ۱.۷×۱۰۶ (MPN/۱۰۰ mL), ۳.۵×۱۰۴ (MPN/۱۰۰ mL), and ۸.۷, respectively. The concentrations of metals including V, Cd, Co, Cu, Cr, Hg, Ni, Pb, and Zn at the inlet of the treatment plant were measured to be ۳.۹, ۱۴.۵, ۵.۶, ۷۷.۹, ۱۴۲.۴,<۰.۳, ۱۰۴.۰, ۷۳.۸, and ۷۲۰.۶ ppb and at the treatment plant, the corresponding concentrations were<۰.۰۶, ۱۱.۸, ۲.۴, ۱۴.۶, ۱۹.۱,<۰.۳, ۷۳.۱, ۱۰.۸, and ۳۴.۵ ppb. Based on the results, the measured values of some parameters, such as BOD۵ , COD, coliforms, and cyanide in the effluent, were higher than the standards set by various organizations. Therefore, discharging such effluent into the environment can harm the ecosystem; their high values result from the lack of any pre-treatment units in various industries. Hence, by obliging certain industries to pre-treat their wastewater before discharging it into the combined wastewater collection system, the above-mentioned parameters can be adjusted to some extent. In addition, considering the high microbial load of the effluent, continuous disinfection and improvement of the disinfection unit can play a significant role in reducing the microbial load of the effluent.