Research On 2-chloro-5-chloromethylpyridine Inhibition To Biological Nitrification In The Treatment Of Production Wastewater Of Imidacloprid

Recent years,with the rapidly growth of China's urbanization and industrialization,and the expansion of the socialist market economy,the environmental pollution is of great concern.Particularly,water pollution in China has been more and more serious.The development of water resources makes the water pollution further serious.The main solution to dispose of the water pollution is to strengthen supervision measures in wastewater treatment and putting it into effect.Due to the high concern of organic pollutants in pesticide wastewater and the complex composition,the effective treatment is relative difficult.This paper studies the inhibitory effect of 2-Chloro-5-chloromethylpyridine(CCMP)on biological nitrification,in imidacloprid wastewater.In addition,powdered activated carbon(PAC)was added to alleviate the inhibition of CCMP on nitrification.The effects of CCMP on nitrification of odor have been explored by observing the concentration of ammonia,nitrate,nitrite,nitrification rate and nitrification inhibition rate under the condition of different concentration of CC.MP.With the increase of CCMP concentration,the inhibition of nitrification was gradually increased.When the concentration of CCMP increased from 2.0mg/L to 25.0mg/L,the ammonia nitrogen degradation rate was reduced from 7.90mg/(gMLSS·h)to 0.02mg/(gMLSS·h)and the nitrification inhibition rate rise to 99.38%.The reason is that the process of AOB oxidation of ammonia to nitrite nitrogen was inhibited by CCMP,which resulted in the reduction of the nitrification rate.The effect of CCMP inhibition has been tested and control tested,under the conditions of different sludge concentration and the initial concentration of ammonia nitrogen.The result shows that,the inhibition of nitrification by CCMP is a competitive inhibition.The inhibitor CCMP and the substrate ammonia nitrogen compete with the same active center of the enzyme AMO,and the combination of enzyme AMO and ammonia nitrogen was interfered,which reduced the catalytic activity of the enzyme AMO and the nitrification rate.With the increase of CCMP concentration,the inhibition effect was gradually increased.When increasing the concentration of substrate and ammonia nitrogen,the degree of inhibition of CCMP can be reduced.This result is important for the treatment of wastewater containing CCMP and process design.Consulting PACT process in waste water treatment,this paper used the method of addition of PAC into nitrification pool to reduce the degree of inhibition of nitrification.Through different amount of powder activated carbon test,the optimal dosage of activated carbon has been assigned and it was 250mg/L.Experiments were carried out under different temperature and pH conditions.The optimum reaction temperature and pH value were found to be 30? and 8.Under this condition,the degradation rate of ammonia nitrogen was best.In order to verify the effect of adding powdered activated carbon in the practical application,the pesticide factory wastewater has been carried out for simulation test.The operation period was 20 days.The concern of ammonia nitrogen was decreased from 33.50mg/L to 12.70mg/L,and the removal rate was 62.08%.