The Degradation Characteristics Study On Typical Nitrogenous Heterocyclic Cimpounds

Nitrogen heterocyclic compounds is a class of refractory material in coking wastewater.These compounds which has strong toxicity,stable chemical structure and poor biodegradability,has carcinogenic teratogenic,mutagenic effect for the organisms and exists potential hazards for the environment and organisms.The study of degradation mechanism and treatment technology about nitrogen heterocyclic compounds are always been the focus of researchers from all over the world.In this study,pyridine,quinoline and indole are selected as the typical nitrogen heterocyclic compounds to research the characteristics of degradation and the kinetics of denitrification under anoxic conditions.The main methods and conclusions are as follows:1.Using the activated sludge from denitrification section of upflow blanket filter(UBF)as seed sludge,were added to the selection medium with a single carbon source-pyridine,quinoline,indole to do a shaker test.2.With organic matter degradation rate as indicators,research the influencing factors of denitrification process.Batch experiments were carried out at 20?,25?,30?,35? and40?.We could come to the conclusion that at 30?,the pyridine s degradation rate was the highest,which was reaching to97.5%.When the temperature was lower than 30?,the degradation rate decreased significantly.When the temperature was between 25? and 30 ?,the quinoline kept a higher degradation rate.At 30 C,the highest degradation rate was 98.4%.Indole could be degraded well between 30? and 40?.It would reach the highest degradation rate at 35 C.The organic matter's degradation rate was determined in different pH values-6.0,7.0,7.5,8.0 and 9.0.In pH=7.5,the pyridine,quinoline,indole could be removed at 94.5%,98.6%and 94.5%.NaNO3 was used as nitrogen source,changing the concentration of pyridine,quinoline and indole.Denitrification experiments were done at the different C/N(organic theoretical COD/NO3--N)respectively.When C/N was 3,the phenomenon of nitrogen residual was appeared in all the three processes.When C/N was 8,the carbon source and nitrogen source could be degraded quickly.While,the carbon source was residual in the C/N=12.Denitrification process with pyridine,quinoline and indole as sole carbonsource were studied respectively in this paper,getting the optimal solution:30 C,pH=7,C/N=8.3.Batch experiments were carried out to study the nitrite accumulation of denitrification.In the process of denitrification which carbon source was pyridine,the most serious accumulating phenomenon was happened in the condition of C/N=3,and the second was the condation of C/N=12.When the carbon source was quinoline,the highest nitrite accumulation was appeared in C/N=3.And when C/N was 12,the phenomenon of nitrite accumulation was the lowest.Nitrite accumulation was rarely in the process of denitrification which carbon source was indole.4.The research study the variation of nitrate,nitrite and pridine,quinoline,indole during the press of denitrification.The denirification kinetics could be described by the double subtrate Monod equation,qD=qD,maxS/Ks+S D/KD+D,and kinetic parameters could be obtained.In the process of denitrification,the order of the degradation rate was:.The order of the maximum degradation rate of NO-33N was:quinoline>pridine>indole.The order of the maximum degradation rate of NO2--N was:indole>quinoline>pridine.