Study On Bacillus Sp. For Bioaugmentation Treatment Of Coking Wastewater

Coking wastewater is a kind of high concentration organic wastewater containing a large amount of refractory organics,which is one of the most refractory industrial wastewater at present.Coking wastewater treatment process with biological denitrification as the core is widely used at home and abroad,but the removal rate of refractory substances is usually low in coking wastewater.Although some advanced treatment processes have better removal effect,the cost is higher.Therefore,it is a great challenge to select an efficient and economical method treatment.In this paper,the biodegradation of coking wastewater was studied by using Bacillus sp.coupled with co-metabolism matrix,and a scheme was proposed to improve the removal rate of refractory substances without changing the existing biological treatment process,which established a novel technological route for bioaugmentation treatment of coking wastewater,and had important reference value for practical engineering application.The application of the research results will promote the biological treatment effect of coking wastewater,it will have great environmental,social and economic benefits.The paper adopted two self-screened strains,Bacillus proteolyticus strain(YB1),Bacillus velezensis strain(YB2),four co-metabolism matrix(glucose,starch,methanol,ethanol)and activated sludge to treat the coking wastewater.The best co-metabolism matrix was determined by single factor matrix experiment.The optimum conditions of using activated sludge were determined by the domestication of activated sludge and the response surface experiment of activated sludge;The bioaugmentation conditions of the strains coupled with co-metabolism matrix were determined by the single factor experiment of their dosage.The results showed that the degradation effect of activated sludge on coking wastewater was the best when the co-metabolism matrix was methanol,the methanol dosage was 5:1(COD of raw water:COD of methanol),COD could be degraded from 119 mg/l to 39.8 mg/l,and the degradation process was in accordance with the first-order reaction kinetic equation.The concentration of organics was determined by organic carbon analyzer,and the kinds of refractory organics before and after the degradation of coking wastewater were analyzed by GC-MS.The results showed that the refractory organics in coking wastewater was degraded from 47.8 mg/l to 4.2 mg/l,original refractory organics contained phenol,o-phenol,p-methyl phenol,2,3-dimethylphenol,cabbage,indole,1-methyl naphthalene,4-azofluorene,N-phenyl-2-naphthalamine were degraded.Through high-throughput sequencing,furtherd the role of the dominant species in activated sludge in the degradation of refractory organics,indicating that the co-enhancement of YB1 and methanol not only increased the diversity and richness of microorganisms in activated sludge,it also contributed to the enrichment of the dominant phylum that can degrade the refractory organics in the coking wastewater,for example Proteobacteria,Bacteroidota,Chloroflex and so on,and the genus,norank?f??Microscillaceae.