Study On Denitrogenation Effect Of Medical Sewerage With SND-type Biological Contact Oxidation Process

Biological contact oxidation process,which is currently widely used in many hospital's sewerage treatment project,still has some problems such as poor effect of denitrification and denitrogenation,low removal ratio of ammonia nitrogen (NH₃-N) and total nitrogen etc.In order to let sewerage quality bleedered off reach the standard method,some improvements were done based on former engineering, which would have considerable ecnomical benefit.SND(Simultaneous Nitrification and Denitrification),which is a new technology developed from traditional biological denitrogenation theory,is applied to achieve nitrification and denitrification simultaneously in one biological reactor. In this dissertation,biological reactor unit with traditional contact oxidation method were optimized and ameliorated,and a noval biological contact oxidation reactor was designed with the characterical of SND technology.By the comparative test of sewerage treatment effect between SND-type and traditional biological contact oxidation reactor in a comprehensive hospital,some relationship among HRT,C/N and removal ratio of total nitrogen was summarized,meanwhile,the optimal technique condition of SND-type was obtained by the intergration of solo factor analysis and orthogonal experiment,the results were as follows:1):Change of C/N ratio had little influence on the water quality index,both traditional and SND type had strong ability of anti-impact carrying capacity.2):Compared to traditional type,SND-type has some better improment in denitrogenation,that is,the removal ratios of total nitrogen and ammonia nitrogen increased about 14.7%and 25.7%,respectively.3):The optimal thchnique parameter of SND-type biological contact oxidation reactor was:HRT was about 8～9h,organic charge was 60～80 g/m³.d,reflux ratio was 100%,pH was 7.3～8.5,and yield of sewerage sludge was low.Thoughout this dissertation,some important parameters which could be applied to practical design and operation control was obtained and also could provide technique basis to the improvement of hospital's sewerage treatment station with traditional biological contact oxidation reactor.