The Study On Treatment Of High Concentration Sulfate Organic Wastewater By Two-phase Anaerobic Process

One of Jiangxi Biochemical Co., Ltd. brings about high density sulfate organic waste water during the production of gibberellins. The waste water contains sulfate,NH₄⁺-N and COD_cr with high concentration and low pH value, it makes wastewater treatment more difficult, it too difficult to treat by conventional biochemical process. Using UASB, aeration sedimentation and IC treatment to deal with the wastewater, control the condition making the acid-producing bacteria become the preponderant bacteria in the UASB anaerobic reactor, the sulfate reducting bacteria in the UASB deoxidize the SO₄^2- into sulfide, which is to reach the goal of removing the SO₄^2-. Control the aeration tank in feasible aeration volume, making the required hydrogen volume increasing gradually in the tank. The desulfurize bacilus turns the sulphide produced by the UASB reactor into sulfur and removed in settling tank. As the COD_cr and organic load are still high after the above processes, we adopt IC anaerobic reactor to remove COD_cr.This paper using two-phase anaerobic process treatment of high concentration sulfate organic wastewater, by practical engineering debugging and stable operation, the results show that:â‘ In the starting phase, by gradually increasing the concentration of the influent COD_cr and sulfate concentration in the UASB reactor, domesticate sewage sludge. The concentration of the influent water COD_cr and sulfate in the UASB reactor goes from 5000mg/L and 700 mg/L to 13000 mg/L and 1700 mg/L. By making sludge acclimation, the removal rate goes up to 85 % at the end of starting phase. The load rate of sulfate is 5 kgSO₄^2-/(m³.d).â‘¡We use adaptable comprehensive wastewater as the IC influent water. Theconcentration of the influent COD_cr and sulfate is 5000mg/L and 500 mg/L seperately,and at the starting phase the influent volume is 4m³/h, the COD_cr volume load is 5kg/(m³.d) . After 30d starting phase, the average removal of COD_cr in IC reactor goesup to 50%.â‘¢Controls the aeration tank's dissolved oxygen at 0.5—1 mg/L, the desulfurize bacilus can effectively removing sulphide, the removal rate goes up to 90%.â‘£In stablestage, keep the concentration of influent sulfate is 1 500mg/L and the pH value is 6.5, while the sulfate load is 5kgSO₄^2-/m³.d, and the removal rate of it goes up to 80%.⑤The organic load of IC is 13.6 kgCOD_cr/(m³.d), HRT of IC is 6h,concentration of COD_cr is 6000mg/L and pH value is 7.0, the alkalinity is 1 300mg/L(by CaCO₃). The removal rate of COD_cr is 70%.â‘¥UASB effluent NH₄⁺-N concentration is higher than influent concentration, increasing extent is 20%-30%, the NH₄⁺-N removal rate by IC is 20%-27%. Removal rate of NH₄⁺-N by two-phase anaerobic progress have low efficiency.⑦In the stablestage, in both UASB and IC reactor formed 0.2-3.5mm granular sludge. It have high removal rate of sulfate and COD_cr in the high concentration sulfate organic wastewater by two-phase anaerobic progress, but have low efficiency to treat NH₄⁺-N.