Advanced Treatment Of Landfill Leachate By Ozone/Activated Carbon And Regeneration Of Activated Carbon By Microwave Ultraviolet

With the speeding up of urbanization in our country, the production of landfill increases obviously and landfill leachate presents the explosive growth. Landfill leachate has complex compositions and multiple structures so it is hard to reach emission standard when it is treat only by biological method. In 《Standard for Pollution Control on the Landfill Site of Municipal Solid Waste》（GB16889-2008）,Landfill leachate cannot directly discharge into the urban drainage pipe network but it needs to be treated until water quality meet the requirement. So the advanced treatment of landfill leachate is significance.In the study, landfill leachate is from the landfill in Harbin. The concentration of COD is 1550 mg×L^-1 and the concentration of ammonia nitrogen is 75 mg×L^-1. the advanced treatment of landfill leachate uses ozone and activated carbon. Experiments proved that ozone combined with activated carbon had better effect than only ozone and activated carbon. At the same time, we researched the effect of the ozone concentration, the dosage of activated carbon and p H on the results. From experiments, we known the optimal experimental conditions. It was that p H was 4.5, the air flow was 1 L×min^-1, the concentration of ozone was 1.344 mg×L^-1, the dosage of activated carbon was 10 mg×L^-1, The oxidation time for ozone was 30 min and the adsorption time for activated carbon was 180 min. After treatment, the concentration of COD is 93 mg×L^-1 and the concentration of ammonia nitrogen is 75 mg×L^-1. Water quality reached the water quality.Activated carbon was regenerated after the adsorption. The regeneration method was MW/UV. In research, the single factor experiment and orthogonal experiment were done. Experimental conditions such as the system, carrier gases, gas flow rate, microwave power and the reaction time were optimized. From experiments, we known the optimal experimental conditions. It was that microwave power was 400 W, the quality of activated carbon was 5 g. the reaction time was 420 s. carrier gas was air. air flow rate was 0.028 m3×h^-1. After reaction at the optimal experimental conditions, the regeneration rate of activated carbon was 84.5%, the mass loss rate of activated carbon was 5.9%. Through Boehm chemical titration, BET and zero-point charge analysis, we known that the pore volume was 0.48911 cm3×g^-1, the pore diameter was 11.03 ? and the surface area of activated carbon was 886.695 m2×g^-1 after reaction. The pore volume, pore diameter, and the surface area of activated carbon were all reduced. At the same time, zero-point charge was higher.Through GC-MS, ultraviolet-visible spectrophotometry, gel chromatography and chemical and biochemical analysis, we discussed the mechanism of ozone treatment of landfill leachate and the mechanism of activated carbon treatment of landfill leachate. Ozone could directly react with pollutants in landfill leachate. Also, ozone also could generate hydroxyl free radicals and react with pollutants. Activated carbon that removed pollutants in landfill leachate mainly based on physical adsorption and chemical adsorption.