Abstract
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 average inlet concentrations of TSS, TDS, COD, DO, BOD5, cyanide, total coliform, fecal coliform and pH were 1210 mg/L, 2165.5 mg/L, 2187.5 mg/L, 2.4 mg/L, 967.5 mg/L, 20.8 mg/L, 1.3×1010 (MPN/100 mL), 1.2×109 (MPN/100 mL) and 6.7, respectively. Also, the average outlet concentrations of the mentioned parameters were 94.5 mg/L, 2370.4 mg/L, 220.7 mg/L, 5.2 mg/L, 113.4 mg/L, 2.0 mg/L, 1.7×106 (MPN/100 mL), 3.5×104 (MPN/100 mL), and 8.7, respectively. The concentrations of metals including V, Cd, Co, Cu, Cr, Hg, Ni, Pb and Zn at the inlet of the treatment plant were also measured as 3.9, 14.5, 5.6, 77.9, 142.4, <0.3, 104.0, 73.8 and 720.6 ppb and at the treatment plant, the corresponding concentrations were <0.06, 11.8, 2.4, 14.6, 19.1, <0.3, 73.1, 10.8 and 34.5 ppb. Based on the results, the measured values of some parameters, such as BOD5, COD, coliforms, and cyanide in the effluent, were more than the standards set by various organizations. Therefore, discharging such effluent into the environment can harm the ecosystem; their measured values could be due to the lack of any pre-treatment units in various industries. Hence, by obligating the establishment of pre-treatment for some industries before discharging the wastewater in combined wastewater collection system, the above mentioned parameters can be adjusted to some extent. In addition, due to 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.