The Screening Of Heterotrophic Nitrification-aerobic Denitrification Bacteria Pseudomonasmendocina TJPU04 And Its Denitrification Performance

With the rapid development of industry,a large amount of nitrogen-containing sewage was produced and discharged in actual production,causing serious pollution to water.The removal of nitrogen in water has become a top priority in wastewater treatment.In this paper,a nerw heterotrophic nitrifying-aerobic denitrifying(HN-AD)bacterium was isolated from different sources,and the HN-AD ability of the strain was investigated.Moreover,the effect of different factors on the nitrogen removal performance were investigated.Furthermore,the degradation performance of the strain in the real wastewater was further discussed.The main contents are as follows:(1)A strain of HN-AD was isolated and identified by morphological observation and 16SrDNA gene sequence analysis.The strain was identified as Pseudomonas mendocina and named as TJPU04.(2)We explored the nitrogen removal performance with ammonia nitrogen(NH4+-N),nitrogen nitrate(NO3--N)and nitrite(NO2+-N)as the sole nitrogen source,and with NH4+-N/NO3+-N and NH4+-N/NO2--N as mixed nitrogen source.In NH4+-N nitrification medium(HNM),the removal efficiencies of COD,total motrogen(TN)and NH4+-N of strain TJPU04 after 30 h were 60%,97.01%and 100%,respectively.In NO3--N denitrification medium(ADM-1),the removal efficiencies of COD,TN and NO3--N of strain TJPU04 after 26 h were 35.60%,82%and 970%,respectively.In NO2--N denitrification medium(ADM-2),the removal efficiencies of COD,TN and NO2--N of strain TJPU04 after 30 h was 50%,88.2%and 99.3%,respectively.After the strain TJPU04 was cultured for 30 h in denitrification medium with NH4+-N/NO3--N as mixed nitrogen sources(SND-1),the removal efficiencies of TN,NH4+-N and NO3--N in 30 h were 88%,96%and 87%,respectively.After the strain TJPU04 was cultured for 30 h in denitrification medium with NH4+-N/NO2--N as mixed nitrogen sources(SND-2),the removal efficiencies of TN,NH4+-N and NO2--N in 30 h were 76%,97%and 32%,respectively.These results indicated that the strain TJPU04 exihibited excellent HN-AD capacity.(3)The strain TJPU04 had a higher nitrogen removal performance with the sodium citrate as the carbon source,higher C/N ratio,over a wide range of nitrogen concentrations and under sterile and non-sterile conditions.Bacterical cellulose(BC)was used as immobilized carrier material to investigate the nitrogen removal efficiency of strain TJPU04.The result showed that the strain TJPU04 was tightly integrated with BC carrier,and eventually showed a good nitrogen removal efficiency.(4)The strain TJPU04 could adapt to the harsh environment with' a salt concentration of 0-4.5%.It showed a high nitrogen removal ability at 3%salt concentration and different N concentrations.After being immobilized with polyvinyl alcohol(PVA)membrane,strain TJPU04 still maintained a high nitrogen removal capacity in the nitrogenous wastewater at 3%salt concentration.(5)The removal efficiencies of NH4+-N?NO3--N and TN by strain TJPU04 in real wastewater were 91%,52%and 75%,respectively.This results suggested that the strain exhibited stronger nitrogen removal ability in real wastewater.