Screening And Microbial Characteristic Study Of A Halophilic Aerobic Denitrification Strain Photobacterium Sp. LP

An assimilatory nitrate reducing strain photobacterium sp. LP can denitrify and remove COD, P in the fully aerobic conditionhigh-efficiency just in one reactor. It can save the infrastructure and system operation costs. Strain photobacterium sp. LP is a contaminating bacteria from the strain 503-4 and was determined to be a photobacterium.The best denitrifying conditions of photobacterium sp. LP are salinity 3%, C/NNH4+=13, C/NNO3-=9, pH=7.69, temperature 25℃-30℃ and the dissolved oxygen (DO=7.10 mg/L). photobacterium sp. LP could remove 108.24 mg/L nitrate, 32.21 mg/L TP,1543.6 mg/L CODCr in mediums of 109.27 mg/L nitrate,242.68 mg/L TP,1639.28 mg/L CODcr and remove 119.31 mg/L ammonia,34.09 mg/L TP,1707.57 mg/L CODcr in mediums of 119.39 mg/L ammonia,238.44 mg/L TP,1729.16 mg/L CODcr. The microbial biomass nitrogen amount of photobacterium sp. LP is numerous in logarithmic phase, about 103.42 mg/g in nitrate mediums and 85.29 mg/g in ammonia mediums, the activated sludge of photobacterium sp. LP may be used as fertilizer to recycle N and P in the effluent.The experiment proved that:1. A considerable volume of ammonia can control the nitrate reduction and nitrite reduction; 2. There is no NOx gas producing in the reduction; 1 and 2 prove that photobacterium sp. LP is an assimilatory nitrate reducing bacteria; 3. The ammonia removing all depend to the assimilation of photobacterium sp. LP which can not nitrify the ammonia.The experiment proved that:A certain nitrate reductase and reduzate related to the reductase are in the cytomembrane and non-water fractions, the activity of the nitrate reductase is effected by the temperature; There is no nitrate reductase related to NADH, NADPH, reduced methyl viologen in the supernate from the ultrasonication; There is no nitrate reductase or reduzate related to the reductase in the supernate from the ultrasonication.The organic effluent Referred to the essay is from WeiHai XunShan fishery company in Shandong province, which is in that case:salinity≈4.7%, C/N≈20, pH≈2.1. The main pollutants of the organic effluent are NH4+, NO2-, NO3-, organonitrogen, COD, P. photobacterium sp. LP can adapt to the condition of high salinity and high C/N and remove COD, P meanwhile. the hollow fiber membrane Referred to the essay can stop photobacterium sp. LP from going into the yielding Water,the author used photobacterium sp. LP to treat the pre-treated waste water in the shake flask and to treat the simulation wastewater in the hollow fiber membrane-MBR, the concentration of TN, CODcr, TP can drop below the concentration of GB 18918-2002 in the shake flask and sometime in the hollow fiber membrane-MBR, but the arrange mud law and the cost of the hollow fiber membrane washing and changing was not fit for the practical application.