Study On Nitrite Removal In Landfill Leachate With AMO Technics

Landfill leachate contains a variety of pollutants such as organic matter, ammonia, heavy metals, which is high in concentration and often change with time, weather etc. These lead to the difficulty in treating landfill leachate.This study was carried out to investigate the feasibility of integrated biological and physic-chemical treatment technologies in treating leachate,which is from Erfeishan refuse landfill in WuHan. The technics of"AMO"(Anoxic-Micro levels of oxygen-Oxic processes)was used for removing high concentration organic matter and ammonia in leachate. The"M"segment realized the Shortcut nitrification by controlling the DO and pH, then we return the mixture of sludge and wastewater to"A"segment, where the Shortcut denitrification happen.Some of studies investigate the main factors to Shortcut nitrification /denitrification in this experiment. The results demonstrated that there are several chief factors to nitrite accumulation during shortcut nitrification in the technics: ammonia,the pH,the temperature and the dissolved oxygen(DO)concentration; when the activated sludge loading of NH₄⁺-N was 0.64kgNH₄⁺-N/(kgMLSS·d),the maximum ratios of NO2--N/NO3--N could achieve 85.6%; the NO2--N can accumulate heavily when the pH was 7.5 and the DO was 0.75mg/L. We still did some research about the process of Shortcut nitrification /denitrification, and got some ways to elevate the ratios of nitrite removal.The experiment results show that the AMO technics can implement the Shortcut nitrification /denitrification effectively when pH was 7.5,the DO was 0.75mg/L and the maximum activated sludge loading of NH₄⁺-N was 0.64kgNH₄⁺-N/(kgMLSS·d),at the same time, the NH₄⁺-N and the COD can also be removed effectively. So this study have an important role of guiding to the practice in nitrite removal of landfill leachate.