Key Laboratory of Northwest Water Resource,Environment and Ecology < Ministry of Education > ,School of Environmental and Municipal Engineering,Xi’an University of Architecture and Technology College of Architectural and Civil Engineering,Xinjiang University
The high concentration dissolved oxygen in the internal reflux liquid is a common problem in the activated sludge process. In order to eliminate the influence of dissolved oxygen in internal reflux liquid on denitrification process simply and effectively,the feasibility of strategies such as limited increase of C/N ratio of the influent,introduction of endogenous oxygen consumption process and adjustment of influent carbon source components were investigated in typical traditional A/O process and step-feeding A/O process. The limited increase of C/N ratio had a certain effect on eliminating the dissolved oxygen in the internal reflux liquid of the traditional A/O process,but the effect was weakened in the step-feeding A/O process. The introduction of endogenous oxygen consumption process had an obvious effect on elimination of the dissolved oxygen in the internal reflux liquid of the two processes. The strategy could ensure that the carbon source in the anoxic section was not consumed by the dissolved oxygen,so that the denitrification could proceed normally. The carbon source components in the influent had a certain effect on the elimination of dissolved oxygen in the internal reflux liquid. Excessively high content of slowly biodegradable organic matter was detrimental to the elimination of dissolved oxygen in the internal reflux liquid of the traditional A/O process and had a negative impact on the removal of TN.However,the slowly biodegradable organic matter would not be completely degraded under aerobic conditions and would be transferred to the anoxic section along with the reflux in the step-feeding A/O process,which was beneficial to eliminate dissolved oxygen in the internal reflux liquid.