Study On The Nitritation Of The Mid And Late Landfill Leachate

The new theory of biological nitrogen removal such as short-nitrification (nitrosation) denitrification and ammonia oxidation(ANAMMOX) provide a new perspective to solve the high concentration ammonian removal of the mid and late landfill leachate.But how to achieve the lasting accumulation of the nitrous-nitrogen effectively and stability is still a key to the development of the new nitrogen removel above all.This research with Qingdao small Jianxi landfill's seven-year leachate,focusing on the influence of the ammonian concentration of influent water to the start of Nitrosation reactor,and the specific conditions of the impact on water quality Nitrite-nitrification factors of the Asian nitrification treatment of leachate late in the best condition operating parameters.First of all in control of dissolved oxygen(DO) in about 1.0mg/L,the temperature around 30℃,not regulate the conditions of pH and alkalinity,divided to the six stages of gradually raising water ammonian concentration,started the nitritation reator.Identified that in the phase of the Nitritation reactor start-up,the highest concentration of ammonian of water was controled in 1000 mg/L around.Secondly,the study on the best operational conditions of the nitritation reactor: the main factors including Hydraulic Retention Time(HRT),Temperature,Dissovled Oxygen(DO),pH and alkalinity were discussed;and the best operational conditions were attained.The experimental results were as follows:①In view of the specific water quality of the mid and late landfill leachate,control DO concentration 0.7-1.1 mg.L^-1,HRT 5d,temperature at 25～30℃,pH＞7.0,Surplus alkalinity is higher than 350mg/L(as CaCO₃),used the high sludge density(about 4g/L) and the long sludge age,the SBR could realize the stable nitrite nitrogen accumulation. ②The alkalinity amount in the reactor was the critical factor for nitrous-nitrogen build-up,when the hydraulic retention time was plentiful for the ammonium-oxidizers' growth rates.③When the temperature was in 25～30℃,it isn't an obvious influence factor to the accumulation of the nitrous-nitrogen.④Regarding the mid and late landfill leachate,DO wasn't a leading factor for nitrous-nitrogen accumulation.⑤Through the research of the primary factor affects the nitritation reactor,the discovery realizes the nitrous-nitrogen lasting stable accumulation is the result of each influencing factor combined action.For example the temperature and the sludge density influence system DO concentration level,HRT may affect in system's alkalinity and so on.Therefore,controlling factor's the determination not only need embarks from the bacillus nitrosomonas and the nitric acid fungus two kind of bacteria's different dynamics characteristics,moreover must unify the concrete water quality characteristic,and take care of the processing craft and the operating condition.