A comprehensive study on opium pharmaceutical wastewater treatment in laboratory and semi-industrial scales

The wastewater of an opium pharmaceutical industry was successfully treated using a combined process of electrocoagulation/flotation (ECF), peroxone (H2O2/O3) and adsorption filter of granular activated carbon (GAC) in a three-step operation (ECF → H2O2/O3 → GAC), in a lab and semi-industrial scales. The effect of the operating parameters such as initial pH, current density, residence time, injection dose of H2O2, the ratio of H2O2/O3 and time of adsorption process was optimized in both scales. On the lab-scale, the removal efficiency of COD, Color, TDS, TSS, electrical power consumption, electrode consumption, and operating costs have been studied. In the ECF process, the maximum removal efficiencies of COD, color, TDS and TSS were 64%, 60%, 61% and 50%, respectively. The optimum pH, ozonation time, hydrogen peroxide concentration and the ratio of H2O2/O3 in the peroxone process are 8, 45 min, 900 mg/l, 0.3 H2O2/O3, respectively. After ECF and peroxone processes, the maximum removal efficiencies of COD and color increased up to 84% and 62% and after the adsorption process, the maximum removal efficiencies of COD, Color, TDS, and TSS increased up to 99.2%, 99.0, 99.0 and 99.1%, respectively. The performance of each reactor in the semi-industrial scale was also evaluated. After the treatment operation in the ECF → H2O2/O3 → GAC semi-industrial pilot reactor, the COD removal efficiency, Color, TDS and TSS of opium wastewater reached 96%, 99%, 99% and 99%, respectively. The excellent performance, as well as the low operating cost, confirmed that this integrated system is highly applicable for the advanced treatment of opium pharmaceutical industry wastewater.