Biological Nitrogen Removal Of Landfill Leachate

Leachate is the major environmental problem of landfill. It is a kind of high-density organic waste water. The decomposition of municipal garbage and the precipitation are the principal caused that produce the leachate. At present, the treatment of leachate is still a world-wide problem because of the complex component, worse biodegradability and much fluctuation of water quality and water quantity. Almost twenty kinds of poisonous, hazardous carcinogenic substances such as aromatic amine have been detected in leachate. Leachate should pollute the cropper and aquatic severely if it discharged into rivers, reservoirs and soil without any innocent treatment. And it should invade human' s body, caused various disease, badly endangered the health of the residents and environment. In addition, both the ground water and the surface water would be badly polluted around the landfill place.Based on the systematic analysis of the research results on the leachate characteristics and its treatment methods at home and abroad, it is convinced that ammonia-nitrogen should be removed and limited prior to the biological process . It put forward higher requirement on the selection of the treatment process.By comparison different biological nitrogen removal process , it has been approbated that high strength ammonia-nitrogen present in landfill leachate had severely inhibition effect to the microbe in the nitrous nitrification-denitrification process and a large number of energy had been retrenched. The key to nitrous - denitrification process was to control the condition during the nitrification phrase and immobilize the bacteria.To solve the problem, a large number of experiments about suitable parameters during the nitrosation phrase, especially about the removal rulesof ammonia-nitrogen were performed. Mixed bacterium in the actived sludge was separated primary and immobilized. All of these assured the quantity of bacterium in leachate and established the base of industrialization manufacture.Six kind of bacteria were isolated from the mixture, and it was approved is that when the temperature was 30-35 , pH was 8. 0, DO<1. 2mg/L, the condition was adapted to Nitrosomas and the rate of remove about ammoniate was more than 80%. The repression to microbe should be reduced effectively and the following denitrification should be trouble-free operation.In immobilization experiments, the important parameters such as embed material, additive, the rate between sludge and embed material quality (W/V) and cross linkage time were studied. It was approved that the immobilized spherule had high biological activity, strength and mass transfer capability when PVA concentration was 9. 0%, CA concentration was 1. 0%, W/V was 1:1 and the cross linkage time was 24 hours.