Experimental Research Of Advanced Oxidation Processes In The Treatment Of Landfill Leachate

With the fast development of the city, there will be more and more garbage from people's production and living, at the same time, a great deal of landfill leachate is produced. Because landfill leachate contains variety of pollutants and the quantity of landfill leachate varies greatly, landfill leachate treatment becomes a major problem. Biochemical Treatments has a better removal effect, but the effluent is still difficult to meet the more strict discharge standards. At this time, landfill leachate hardly has biodegradability and Biochemical Treatments has no effective effect, but Advanced Oxidation Processes?AOPs? can improve the biodegradability of landfill leachate greatly even break down the refractory organics. Advanced Oxidation Processes has attracted widely attention in recent years for its unique advantages in treating landfill leachate, such as degrading organic matters completely, reacting rapidly without secondary pollution and being suitable for a wide range of water quality.This paper presents the recent research progress of Biochemical Treatments, Membrane Processes and Advanced Oxidation Processes used in treating landfill leachate at home and abroad. Fenton, electro-catalytic oxidation, ozone oxidation are used in the advanced treatment of biochemical effluent of landfill leachate in small static test. The suitable oxidant and optimal operating parameters can be choosed through comparing the removal rate of COD that as evaluation index. For providing a reference for the application of AOPs in landfill leachate, the comparison was made among these AOPs on the aspects of reaction mechanism, the treatment results, treatment costs, ease or difficulty of operation, engineering applicability, etc. Specific experimental conclusions are as follows:?1? Fenton is used in the advanced treatment of biochemical effluent of landfill leachate. When dosage of FeSO₄·7H₂O is 10 mmol/L, dosage of hydrogeo peroxide is 40 mmol/L, initial pH value is at 3, the reaction time is at 60 min, the removal of COD is 73% at the optimum condition.?2? Electro-catalytic is used in the advanced treatment of biochemical effluent of landfill leachate. When the distance between electrode plates was 1.0 cm, current density is 40 mA/cm2, the reaction time is at 90 min, the removal of COD is 58% at the optimum condition.?3? Ozone oxidation is used in the advanced treatment of biochemical effluent of landfill leachate. When the ozone dosage is at 20 mg/min, the reaction time is at 90 min, the removal of COD is 60% at the optimum condition.?4? Ozonation combined with ultraviolet irradiation?UV/O₃? is used in the advanced treatment of biochemical effluent of landfill leachate. When the ozone dosage is at 20 mg/min and UV is at 20 W, the reaction time is at 90 min, the removal of COD is 74% at the optimum condition.?5? Ozonation combined with ultraviolet irradiation?UV/O₃? is used in the advanced treatment of continuous flow of landfill leachate biochemical effluent. When the ozone dosage is at 20 mg/min and UV is at 20 W, flow rate of biochemical effluent of landfill leachate is 7.5 mL/ min, the reaction time is at 90 min, the removal of COD is 72% at the optimum condition.?6? Afterwords, Ozonation combined with ultraviolet irradiation?UV/O₃? is used in the advanced treatment of continuous flow of landfill leachate nanofiltration effluent. When the ozone dosage is at 5 mg/min, UV is at 20 W, landfill leachate biochemical effluent flow rate of 7.5 mL / min, the reaction time is 120 min, the removal of COD is 65% at the optimum and the value of COD is about 100 mg/L. It can meet the general emission standard of landfill leachate, but can not meet the emission standards of Beijing. Then two-stage processes is considered in pilot test and add a biological aerated filter?BAF? in the middle.?7? Ozonation combined with ultraviolet irradiation?UV/O₃? is used in the advanced treatment of a pilot test of continuous flow nanofiltration effluent of landfill leachate in two-stage processes. When the power of the ozone generator is 3 kW, concentrations of ozone is 90 mg/L, ozone dosage is 180 mg/L, UV is at is 2.4 kW, the removal of COD is 57% in the first processes. BAF is used in the treatment of the landfill leachate in the middle. When the power of the ozone generator is 2 kW, concentrations of ozone is 70 mg/L, ozone dosage is 140 mg/L, UV is at is 2.4 kW, the removal of COD is 50% in the second processes. The value of COD is less than 60 mg/L and meets the emission standards of Beijing.