Pharmaceutical wastewater is one of the major complex and toxic industrial effluents containing little or no biodegradable organic matters. In this study, H2O2/UV based advanced oxidation process (AOP) was used to remove organic materials from pharmaceutical industry effluent. For the chemical oxygen demand (COD) removal radiation of medium pressure mercury vapor UV lamp was used in the presence of hydrogen peroxide (H2O2/UV). Results indicated that the efficiency of COD removal depends on the initial concentration of H2O2, oxidation time and pH. The efficiency of COD removal at low H2O2 concentration was very low even coupled with UV light, which can be attributed to the low generation of hydroxyl radicals (OH •). At high concentration of H2O2 (500 mg/dm 3) and optimum pH (pH = 4), 87.6% removal efficiency could be achieved during 70 min oxidation. For high concentration of H2O2 (500 mg/dm 3) at pH 3 and 7, the maximum COD removal efficiency was 28.5% and 15.2% respectively, indicating significant roles of pH and H2O2 concentration in the process of COD removal.

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A B S T R A C TLandfilling leachate contains a high concentration of organic and inorganic pollutants. The present study was aimed to evaluate the efficiency of the electrocoagulation system in removing chemical oxygen demand (COD) and ammonia-nitrogen (NH 4 -N) from leachate. The paper investigated the factors affecting removal efficiency such as current density (187.5, 375, and 562.5 A/m 2 ), electrode material (Al and Fe), and electrolysis time and pH of the solution (6.5 ± 0. 2). The results indicated that, in optimum conditions, the highest COD and NH 4 -N removal efficiencies were 66 and 63%, respectively. According to the results, performance of the Al electrode was better than that of the Fe electrode in terms of COD and NH 4 -N removal. Therefore, the results showed that electrocoagulation can be applied for the leachate pretreatment as a feasible and reliable technique.

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