Study On The OGO Process For Simultaneous Nitrification And Denitrification

OGO process has been formed as a modification of OCO process through test research. As a advanced technology, it has the functions of phosphorus removal and denitrification with facilitation,effectiveness and economic. OGO technology has already been approved as Utility Model Patent (ZL2005 2 0010545.7). According to the characteristic of OGO system, the dissertation carried out test and analysis on the simultaneous nitrification and denitrification (SND).The followings were studied:①The nitrogen removal effect and mechanism of simultaneous nitrification and denitrification in the OGO system were analyzed;②The effect of operating parameters (dissolved oxygen (DO) concentration, influent C/N ratio, mixed liquor suspended solids (MLSS) etc.) on the simultaneous nitrification and denitrification were studied;③Research has been done to study the relation between the activated sludge characteristic and operational effects of the OGO system;④The nitrogen removing microorganisms in OGO system were tested through the experiment.According to the above study, it is concluded that:1) The OGO system occur obvious phenomena of simultaneous nitrification and denitrification in the out-loop; when influent total nitrogen(TN) and ammonia nitrogen(NH4+-N) are 31.15～42.26 mg/L and 27.53～38.58 mg/L respectively, the average removal efficiencies of TN, NH4+-N achieve 75.47% and 84.29%; 57.93% of the nitrogen removal amount is achieved by simultaneous nitrification and denitrification in the OGO system; 2) The change of DO concentration, influent C/N ratio and MLSS influence the SND effect significantly in the OGO system, the suitable operating condition is: the DO concentration in the middle of the aerobic area is about 2.0mg/L, C/N ratio is from 7 to 18, MLSS is about 3000mg/L; 3) The correlation between nitrobacteria and nitrate nitrogen(NO3--N) is 0.98 , while the correlation between nitrosobacteria and NH4+-N is -0.91; 4) Bioreactor macro-environment, floc micro-environment and novel microorganisms with non-traditional biochemical activities for SND are existed in OGO system. The study is one of the Netherlands government grant projects (economic feasible processes and demonstrations for environmental infrastructures in western China's small towns) and it is a part of the project"Treatment technique research of municipal sewage based on ideal flow pattern", which is funded by state's natural science foundation. This research acquired the values of important parameters that could be used in actual design and control as well as provide support for the engineering utilization of OGO in municipal wastewater treatment.