Degradation Ability Of Nitrogen Heterocyclic Compounds By Achromobacter Sp. And Bio-augmentation Effect Of Activated Sludge For Coking Wastewater

Quinoline and pyridine are typical nitrogen-containing heterocyclic compounds that widely exist in coking wastewater,and substandard emissions can cause serious harm to the environment and human body.This topic explored the degradation characteristics and metabolic pathways of quinoline and pyridine by Achromobacter sp.under the co-metabolism,laying the groundwork for analyzing the metabolism of organic substances in coking wastewater.Using Achromobacter sp.as the strain of bio-augmentation to treat actual coking wastewater,the relationship between the treatment capacity of activated sludge and the changes in microbial community structure was analyzed.It lays a theoretical foundation for the application of the strain to the actual wastewater treatment of nitrogen containing heterocyclic compounds.Achromobacter sp.was prepared into a desicant using freeze-drying method,and manganese sulfate,sodium glutamate,and sucrose were selected as freeze-drying protectants.The survival rate of Achromobacter sp.reached 91.92%.The use of dry bacterial agents instead of Achromobacter sp.seed solution for bio-enhanced treatment of coking wastewater showed comparable degradation effects,indicating the successful preparation of dry bacterial agents.The degradation rates of quinoline and pyridine by Achromobacter sp.under co-metabolism reached 99.39%and 98.06%,respectively,with methanol and glucose as the optimal co-metabolic substrates.The growth kinetics could be described by the Haldane model,and the kinetic parameters were higher than those of the currently reported degrading bacteria.The organic composition of the degradation solution was analyzed by GC-MS,and it was concluded that quinoline conformed to the metabolic pathway of 8-hydroxycoumarin.The metabolic pathway of pyridine was the cleavage of chemical bonds between N and C2 on the ring,resulting in the formation of intermediate products NH₄⁺and glutaraldehyde.Achromobacter sp.and methanol were used together to enhance activated sludge to treat actual coking wastewater.The results showed that the TOC removal rate of coking wastewater reached 95.02%,and the degradation effect was significant.The microbial community in activated sludge was analyzed using high throughput sequencing technology.The results showed that the abundance of Achromobacter sp.gradually increased with the increase of reaction time,and it became a dominant strain.Moreover,the abundance of the original dominant microbial community in activated sludge accounted for a large proportion,which was not affected by this strain.These dominant bacteria played an important role in the degradation of coking wastewater.