| The effluents from alkaloid industry contain high levels of organic matter, alkalinity, salinity, color and sulphate. The treatment of this complex industrial wastewater was attempted in two stages anaerobic reactors. The effects of COD, conductivity, pH, alkalinity, sulphate and TKN on anaerobic treatment were evaluated. When the reactors were fed with original wastewater, VFA’s were accumulated in the presence of 25,794 mg/L COD and 30.2 mS/cm conductivity of the raw opium wastewater even at OLR of 1-3 kgCOD/m 3 day. However, stepwise dilution was applied and COD removal of 90% was achieved at OLR of 7-8kgCOD/m 3 day as the conductivity and COD were reduced to 20 mS/cm 20,000 mg/L, respectively. Based on the findings of this study, highly concentrated wastewaters of opium alkaloid industry wastewaters can be treated with anaerobic digestion and significant reduction of COD can be achieved. |