Study On The Removing Of NH₃-N In Landfill Leachate By Vacuum-pumping

Landfill leachate is a kind of high concentration organic wastewater which contains lots of components and is disposed difficultly. For landfill leachate, biologic method is a way that applies far and wide and the cost is lower among the ways of treatment. However, duing to high concentration of NH₃-N existed in leachate, high concentration of NH3-N will seriously restrain the bio-chemical effect of microbiology and depress efficiency of biologic treatment. So before biologic treatment to landfill leachate, removing high concentration of NH3-N in it is the predeterminative condition which guarantees and enhances the biologic treatment effect. Among multitudinous ways of removing nitrogen method of landfill leachate, the method that is most extensive application and the cost is lowest is the air ammonia stripper method. But since it's necessary for this method to add multitudinous medicament in the landfill leachate to adjust pH to 11 above first, at the same time, the facility is easily dirtied in the process of stripping, the application of it is limited.A absolutely new thought is adopted as and a method is conceived to remove nitrogen in landfill leachate by negative vacuum pumping and systemic facility in this research. So that it is expected to establish a method whose efficiency is higher and cost is lower than ammonia stripper removing high concentration NH3-N from the landfill leachate and consider the recycle of removed NH3-N and the reuse of resource.We confirm the feasible, the reliability and the superiority of removing nitrogen by vacuum pumping, at the same time, we summarize the rule and the optimal technical condition of removing NH3-N in the landfill leachate by vacuum pumping by a series of experiment and research.The conclusion of this experimental research is below:(1)A new method and technique of removing high concentration NH3-N in landfill leachate is initiated (2)We develop a suit of device removing NH3-N in the landfill leachate by vacuumpumping independently, so provide the technical feasibility with guarantee (3)It's proved that this technique is a green and environmental technique through our research, because it overcomes the intrinsic disadvantage of ammonia stripper and turns NH3-N into pure ammonia solution which is recycled into new resource.In this research, it's concretely obtained important conclusions below: (l)It's not only feasible but also high efficient to remove high concentration NH3-N in landfill leachate by adopting as vacuum pumping(2)The optimal vacuum of removing nitrogen by vacuum pumping is 200 300mmHg, and the optimal retention time is 0.75^lh. The maximal rate of removing nitrogen is up to 95% in this experiment, and the maximal absorptivity is 72.34% by simply putting NH3 that is removed into the water and absorbing it (3)The obtained ammonia solution can be directly used as leaf fertilizer for plant, and it's also can be ulteriorly purified and concentrated as the materials in chemical fertilizer industry(4)The method of removing nitrogen by vacuum pumping can absolutely replace ammonia stripper at present and become a excellent and green pretreatment technique of removing nitrogen before biologic treatment for landfill leachate (5)The technique of removing nitrogen by vacuum pumping is not only applied in landfill leachate but also in any industrial wastewater which contains high concentration NH3-N.