| In the north of China, warm in winter and cool in summer, water temperature difference greatly, it makes great difficulties for sewage treatment, it is of great significance to screen an efficient psychotropic bacterium for low-temperature wastewater and room-temperature wastewater. Biological wastewater treatment has been widely used, it’s has a lot of advantages including small secondary pollution, handling completely, low cost, technology simple, low energy consumption, high organic matter degradation rate and convenient operation, etc. microbial plays the leading role in Biological wastewater treatment, and the growth of microorganisms are often affected by various factors, the temperature is an important factor affecting the effects of biological wastewater treatment. Chemical oxygen demand (COD) refers to the consumption of oxidant when strong oxidizer handle water, It is one of the indicators of relative contents of organic matter, an important parameter of wastewater treatment,an important indicator of water pollution monitoring.An essential way to understand the advantages of activated sludge bacteria species by micro flora structural analysis of activated sludge and isolations of an efficient psychotropic bacterium in the low temperature (4℃);and study the degradation of organic matter in wastewater of the superiority strain at low-temperature (4℃) and room-temperature (25℃).To analyzed microbial diversity of activated sludge which has been domesticated at low-temperature with PCR-RFLP technique, Results show that the main psychrotrophs in activated sludge can be divided into 11 types,4 generas, it is Pseudomonas sp., Arthrobacter sp., Acinetobacter sp., Chryseobacterium sp., and most number of psychrotrophs are pseudomonas,69.6%, which to degradation of the organic matter in sewage at the low-temperature.Strain DW1 was isolated from activated sludge which has high efficient degradation rate to organic matter; its removal rate of COD reached 67.7%, the colony of DW1 had pale pink, circle, moist, neat, gram positive, DW1 was tentatively identified as Pseudomonas sp. based on its morphological, physiological and biochemical features and its 16SrDNA sequence analysis. The bacteria optimum growth temperature was 30v, and the optimal growth pH was 8.0, the optimum growth carbon source was glucose, the optimum growth nitrogen source was yeast powder, and had a certain tolerance to salt.Study the influence of different factors on the dehydrogenase activity, based on mechanism of dehydrogenase activity(DHA), its COD removal efficiency was analyzed under different factors(Running time, initial COD, inoculation quantity, pH).,Furthermore, it was compared low-temperature with room-temperature (25℃) in dehydrogenase activity and degradation ability. The results showed that the optimum temperature of dehydrogenase was 25℃, and optimum pH was between 6.0～9.0, with fluid amount was 60 ml/250 ml, DWl strain had the highest removal rate of COD were 71.2%,78.8% respectively in low-temperature, room-temperature; had the highest DHA activity were 11.35μgTF/(mL.h),15.11μgTF/(mL.h) respectively in low-temperature, room-temperature. Strain DW1 showed higher removal capacity and DHA activity at low-temperature and room-temperature, show that the strain on the northern area of sewage treatment will have great development potential and good prospects for development. All of these indicated that strain DWl had a broad application prospect and good prospect to sewage treatment in the northern area of China. |
PDF Full Text Request