Screening And Application Of Nitrifying Bacteria Immobilization Materials

Excessive content of ammonia and nitrite in water bodies is an important factor causing water pollution.High concentration of ammonia and nitrite nitrogen will lead to a large number of algae reproduction,insufficient dissolved oxygen in water bodies,directly threatening the life activities of water organisms and causing explosive diseases,and serious imbalance of water ecological environment.This study selected the seven kinds of materials of nitrifying bacteria preparation filling bag,and studied the removal effect of ammonia and nitrite after putting seawater nitrifying bacteria and freshwater nitrifying bacteria into the filling bag,selected two kinds of materials with better effect,applied to the eutrophication of water body purification and improvement of aquaculture water,adopted the flora composition of high-throughput sequencing method.The results are as follows:(1)Seven materials including 250 mesh sieves,300 mesh sieves,adhesive bonded fabric,ultrafiltration cotton,chemical fiber,bony cotton and flannelette were used to make filling bags,and the purification effect of ammonia and nitrite in simulated water bodies after filling with seawater type and freshwater type nitrifying bacteria preparations was studied.The results showed that flannelette material had the best removal effect.After three cycles of experiments,seawater nitrifying bacteria needed 36 h and 12 h respectively to reduce 50 mg/L nitrite nitrogen and ammonia nitrogen to undetectable levels.Freshwater nitrifying bacteria needed 36 h and 60 h respectively to reduce 50mg/L nitrite nitrogen and ammonia nitrogen to undetectable levels.The effect of 250 mesh sieves was the second.After 3 test cycles,50 mg/L nitrite nitrogen and ammonia nitrogen was reduced to undetectable by seawater nitrifying bacteria after 60 h.Freshwater nitrifying bacteria needed 108 h and 180 h respectively to reduce 50 mg/L nitrite nitrogen and ammonia nitrogen to undetectable.(2)Flannelette and 250 mesh sieves were used to fill nitrifying bacteria preparation,study on the purification effect of eutrophication in seawater and freshwater,the results showed that after 9 d's and 12 d's treatment of the flannelette material filling nitrifying bacteria in seawater and freshwater eutrophication of water bodies,ammonia nitrogen and nitrite nitrogen removal rate were over 94%,COD removal rate was 19%?25%;after 9 d's and 12 d's treatment of 250 mesh sieves material filling nitrifying bacteria in seawater and freshwater eutrophication of water bodies,ammonia nitrogen and nitrite nitrogen removal rate were over 92%,COD removal rate was 21%?27%.(3)Nitrifying bacteria preparation was filled with flannelette and 250 mesh sieves materials to study the purification effect of nitrifying bacteria on water bodies added with 4 kinds of prawn bait.The results showed that ammonia nitrogen produced by the decomposition of prawn bait could be effectively utilized by filling nitrifying bacteria with 2 kinds of materials,and ammonia nitrogen could be further decomposed and transformed.After 14 d,nitrite and ammonia nitrogen could be reduced to 0.11?0.15 mg/L by nitrifying bacteria filled with flannelette,and ammonia nitrogen and nitrite could be reduced to 0.11?0.18mg/L and 0.14?0.20 mg/L by nitrifying bacteria filled with 250 mesh sieves.(4)The high-throughput sequencing method was used to study the changement of seawater and freshwater nitrifying bacteria flora structure after processing eutrophication of water body,the results showed that after a period of time,seawater type of nitrifying bacteria inoculants microbial community richness increased,the relative abundance of Proteobacteria reduced,the relative abundance of Bacteroides and Planctomycetes increased,Nitrosococcus watsonii,Nitrosomonas halophila and Nitrosomonas marina and other ammonia oxidizing bacteria increased in relative abundance,Nitrococcus mobilis and other nitrosomonas reduced in relative abundance.The microbial community abundance of freshwater nitrifying bacteria had not increase significantly,the relative abundance of Proteobacteria decreased,and the relative abundance of Bacteroidetes and Firmicutes increased.Nitrosomonas europaea and other ammonia oxidizing bacteria increased in relative abundance,Nitrobacter winogradskyi increased in relative abundance,and Nitrococcus mobilis decreased in relative abundance.After the treatment of eutrophic water body by nitrifying bacteria,the species of biodegradable organisms such as Arenibacter latericius and Aequorivita aestuarii increased,while the relative abundance of pathogenic bacteria such as Portibacter lacus and Roseovarius aestuariivivens decreased.