The impact of dissolved oxygen(DO)at aerobic phase on the nitrogen removal,extracellular polymeric substances(EPS),microbial activity and microbial community of sequencing batch biofilm reactor(SBBR)have been evaluate...The impact of dissolved oxygen(DO)at aerobic phase on the nitrogen removal,extracellular polymeric substances(EPS),microbial activity and microbial community of sequencing batch biofilm reactor(SBBR)have been evaluated in treating mariculture wastewater.The oxygen uptake rate and nitrification rate declined with DO concentration from 3–4 to 1–1.5mgL^(-1),whereas the denitrification rate had an increment.The activities of nitrifying enzymes reduced with the decrease of DO concentration at aerobic phase,but those of denitrifying enzymes illustrated opposite results.The nitrification and denitrification rates displayed the similar variation tendency with the relevant enzymatic activities as DO concentration decreased.The protein(PN)and polysaccharide(PS)content in EPS decreased as DO concentration declined,whereas the PN/PS ratio increased.The microbial community showed obvious difference as DO concentration decreased from 3–4 to 1–1.5mgL^(-1).The microbial co-occurrence,keystone taxa and sig-nificant difference illustrated some variations at different DO concentrations.展开更多
The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment.During the wastewater treatment,the influence of antibiotics on the perfo...The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment.During the wastewater treatment,the influence of antibiotics on the performance of bioreactor should be well revealed due to their toxicity to the functional microbial community.In this study,the effect of feeding 10-30 mg L−1 sulfamethoxazole(SMX)in influent on the performance of an anoxic/oxic-moving bed biofilm reactor(A/O-MBBR)treating mariculture wastewater and the responding change of biofilm microbial communities was investigated.The COD average removal rate remained at 94.61%-97.34%with the dosage of SMX.Compared with that,the nitrifying removals of NH4+-N and NO2−-N were violently inhibited by 30 mg L−1 SMX and denitrifying removal of the NO3−-N decreased obviously with 20 mg L−1 or more SMX.The microbial community in the successful startup bioreactor was relatively abundant,while the diversity of microbial community decreased with the increase of feeding SMX.The salt-tolerant and SMX-resistant genera Arcobacter,Thiothrix,Desulfuromusa and Nitrosomonas were gradually enriched and finally played a vital role in converting COD and recycling nitrogen and sulfur.Hence,the present A/O-MBBR reactor with the salt-tolerant functional microbiota achieved efficient removal of pollutants in the presence of low concentration(e.g.,10 mg L−1)SMX.展开更多
基金supported by the National Natural Science Foundation of China(No.52070172)the Fundamental Research Funds for the Central Universities(No.201964003).
文摘The impact of dissolved oxygen(DO)at aerobic phase on the nitrogen removal,extracellular polymeric substances(EPS),microbial activity and microbial community of sequencing batch biofilm reactor(SBBR)have been evaluated in treating mariculture wastewater.The oxygen uptake rate and nitrification rate declined with DO concentration from 3–4 to 1–1.5mgL^(-1),whereas the denitrification rate had an increment.The activities of nitrifying enzymes reduced with the decrease of DO concentration at aerobic phase,but those of denitrifying enzymes illustrated opposite results.The nitrification and denitrification rates displayed the similar variation tendency with the relevant enzymatic activities as DO concentration decreased.The protein(PN)and polysaccharide(PS)content in EPS decreased as DO concentration declined,whereas the PN/PS ratio increased.The microbial community showed obvious difference as DO concentration decreased from 3–4 to 1–1.5mgL^(-1).The microbial co-occurrence,keystone taxa and sig-nificant difference illustrated some variations at different DO concentrations.
基金the Fundamental Research Funds for the Central Universities of China(No.201964004)the National Natural Science Foundation of China(No.41977315).
文摘The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment.During the wastewater treatment,the influence of antibiotics on the performance of bioreactor should be well revealed due to their toxicity to the functional microbial community.In this study,the effect of feeding 10-30 mg L−1 sulfamethoxazole(SMX)in influent on the performance of an anoxic/oxic-moving bed biofilm reactor(A/O-MBBR)treating mariculture wastewater and the responding change of biofilm microbial communities was investigated.The COD average removal rate remained at 94.61%-97.34%with the dosage of SMX.Compared with that,the nitrifying removals of NH4+-N and NO2−-N were violently inhibited by 30 mg L−1 SMX and denitrifying removal of the NO3−-N decreased obviously with 20 mg L−1 or more SMX.The microbial community in the successful startup bioreactor was relatively abundant,while the diversity of microbial community decreased with the increase of feeding SMX.The salt-tolerant and SMX-resistant genera Arcobacter,Thiothrix,Desulfuromusa and Nitrosomonas were gradually enriched and finally played a vital role in converting COD and recycling nitrogen and sulfur.Hence,the present A/O-MBBR reactor with the salt-tolerant functional microbiota achieved efficient removal of pollutants in the presence of low concentration(e.g.,10 mg L−1)SMX.
