Removal Of Nitrogen In Water By Carbon Fiber Which Enhanced Formation Of Biofilm By Nitrogen-removing Bacteria

With the acceleration of urbanization,a large amount of domestic and industrial sewage is directly discharged into rivers and lakes,which leads to excessive nutritional load in water bodies,and rivers and lakes are in a state of eutrophication.Reducing nutritional load in water bodies has become one of the practical problems to be solved urgently.At present,carbon fiber(CF)has been used as a biofilm carrier to repair the water environment.Related studies have been carried out at home and abroad,showing that carbon fiber can be used as an excellent carrier for biofilm to control river and lake water pollution and achieve a virtuous cycle of water resources.However,most researches put carbon fiber directly into the water body for treatment,which has the problems of long carbon fiber membrane hanging cycle and poor effect of removing nutrients in the initial stage.In order to shorten the carbon fiber coating cycle and improve its initial processing capacity,this study used a nitrogen removal agent to strengthen the carbon fiber coating,to identify the difference between the nitrogen removal agent reinforced carbon fiber coating and natural film coating,and to study the cultivation The influence of factors such as temperature,carbon-nitrogen ratio,and dosage of inoculum on the effect of carbon fiber membrane hanging,determine the best membrane hanging conditions;Under the optimal membrane hanging conditions,the reduction rate of total nitrogen and ammonia nitrogen in the water body is an evaluation index,Investigate the effect of nitrogen removal bacteria agent to strengthen the nitrogen removal of the carbon fiber membrane;Investigate the impact of carbon fiber dosage,initial total nitrogen concentration and total organic carbon concentration on the nitrogen removal effect;And clarify the relationship between the carbon fiber membrane effect and the nitrogen removal performance.The main research conclusions are as follows:(1)Identified the effect of nitrogen-removing bacteria agent on carbon fiber and its influencing factors.(1)From the aspects of microbial biomass,microbial activity and microbial diversity,the difference between the effect of nitrogen-removing agent-reinforcedcarbon fiber membrane and natural membrane was analyzed and compared.It was found that the effect of the nitrogen removal bacteria agent on the carbon fiber membrane was significantly higher than that of the natural membrane.The peak value of the microbial biomass on the carbon fiber of the nitrogen removal agent enhanced membrane was 10.27 times higher than the peak of the microbial biomass on the carbon fiber of the natural membrane.Significantly reduced;compared with the natural membrane of carbon fiber,the microbial activity of the nitrogen-removing agent-reinforced carbon fiber increased by 2.5 times;In addition,the microbial diversity of the nitrogen-removing agent-reinforced carbon fiber was significantly higher than that of the natural film.(2)From the aspects of microbial biomass,microbial activity and microbial diversity,the effects of culture temperature,carbon-to-nitrogen ratio and the dosage of microbial agent on the effect of carbon fiber film coating were analyzed and compared,and the best film coating conditions were determined.It was found that when the incubation temperature was 35? and the carbon-to-nitrogen ratio was 10,the microbial biomass was the largest and the microbial activity was the highest;When the inoculant dosage was 0.5 g/L,the microbial activity was the highest.With the increase of the inoculant dosage,the microbial biomass was not significant difference.To sum up,under this experimental condition,the best film-hanging condition is the cultivation temperature is 35 ?,the carbon-to-nitrogen ratio is 10,and the dosage of the bacterial agent is 0.5 g/L.(2)Under the best film-hanging conditions,the effect of nitrogen-removing bacteria agent-enhanced carbon fiber on the removal of total nitrogen and ammonia nitrogen in water was explored.(1)The effect of removing total nitrogen.The reduction rate of total nitrogen in water body by carbon fiber reinforced with nitrogen removal agent is 45.33%,while the reduction rate of total nitrogen in water body is 20.00% and 31.33% respectively by carbon fiber and nitrogen removal agent.The effect of carbon fiber on the removal of total nitrogen in water is significantly higher than that of carbon fiber and nitrogenremoval bacteria only,and the reduction rate of total nitrogen is increased by 25.33%and 14.00% respectively;(2)The effect of ammonia nitrogen removal.The reduction rate of ammonia nitrogen by the nitrogen-removing bacteria-reinforced carbon fiber is 84.18%,while the reduction rates of ammonia nitrogen by carbon fiber and nitrogen-removal bacteria are 71.01% and 61.59%,respectively.The removal effect of ammonia nitrogen was significantly higher than that of carbon fiber and nitrogen removal bacteria only,and the ammonia nitrogen reduction rate was increased by 13.05% and22.47%,respectively.(3)The effects of the carbon fiber dosage,initial total nitrogen concentration,and total organic carbon concentration on the nitrogen removal effect of the nitrogen-removing bacteria-enhanced carbon fiber were investigated,and the correlation between the film effect and nitrogen removal performance was analyzed.(1)Effect on removal of total nitrogen and ammonia nitrogen.Under the conditions of this experiment,the total nitrogen reduction rate in the water body was significantly positively correlated with the amount of carbon fiber input,and was significantly negatively correlated with the total organic carbon concentration,but not significantly related to the initial total nitrogen concentration;The ammonia nitrogen reduction rate was related to the amount of carbon fiber input;There was a significant positive correlation,and the correlation with the initial total nitrogen concentration and total organic carbon concentration was not significant.(2)Microbial biomass and microbial activity are related to the reduction rate of total nitrogen and ammonia nitrogen.The correlation between microbial biomass and total nitrogen reduction rate is extremely strong;And the correlation between microbial activity and total nitrogen reduction rate is strong;The correlation between microbial biomass and microbial activity to ammonia nitrogen reduction rate is extremely strong.The innovation of this research lies in its verification of the effect of nitrogen-removing agent-reinforced carbon fiber membranes is significantly betterthan that of natural membranes,and the cycle of reinforced membranes is significantly shorter than that of natural membranes.At the same time,it is revealed that the nitrogen-removal agent-reinforced carbon membranes can be significantly shorter in the short term The removal effect of the total nitrogen and ammonia nitrogen in the water body is improved,and the problem of poor nitrogen removal effect of the natural membrane carbon fiber in the initial stage of repair is overcome.