As an energy and carbon saving process for nitrogen removal from wastewater,the partial nitrification and denitrification process(PN/D)has been extensively researched.However,achieving stable PNinmunicipalwastewater h...As an energy and carbon saving process for nitrogen removal from wastewater,the partial nitrification and denitrification process(PN/D)has been extensively researched.However,achieving stable PNinmunicipalwastewater has always been challenging.In this study,a gel immobilized PN/D nitrogen removal process(GI-PN/D)was established.A 94 days pilot-scale experiment was conducted using real municipal wastewater with an ammonia concentration of 43.5±5.3mg N/L at a temperature range of 11.3–28.7◦C.The nitrogen removal performance and associated pathways,shifts in the microbial community as well as sludge yield were investigated.The results were as follows:the effluent TN and COD were 0.6±0.4mg/L and 31.1±3.8 mg/L respectively,and the NAR exceeding 95%.GI-PN/D achieved deep nitrogen removal ofmunicipalwastewater through stable PN without taking any othermeasures.The primary pathways for nitrogen removal were identified as denitrification,simultaneous nitrification-denitrification,and aerobic denitrification.High-throughput sequencing analysis revealed that the immobilized fillers facilitated the autonomous enrichment of functional bacteria in each reactor,effectively promoting the dominance and stability of the microbial communities.In addition,GI-PN/D had the characteristic of low sludge yield,with an average sludge yield of 0.029 kg SS/kg COD.This study provides an effective technical for nitrogen removal from municipal wastewater through PN.展开更多
Domestic wastewater was treated by combined anaerobic biofilm aerobic membrane bioreactor(MBR) process, and part biomass in MBR was withdrawn to treat with ozone, then the ozonated sludge was returned to anaerobic in...Domestic wastewater was treated by combined anaerobic biofilm aerobic membrane bioreactor(MBR) process, and part biomass in MBR was withdrawn to treat with ozone, then the ozonated sludge was returned to anaerobic inlet. In aerobic MBR, MLSS and DO were controlled at 3000—3500 mg/L and 0 8 mg/L respectively. Comparing the experimental results of two stages, it was noticed that ozonation did not affect the removal efficiency for organics but had a significant influence on the removals of NH 3 N and TN. During the ozonation period of two months, no excess sludge was wasted, and a zero sludge yield was obtained.展开更多
Based on the hypothesis of reducing sludge production under cryptic growth conditions, ozone was used as cell lysis agent to treat excess sludge,and then the ozonated supernatant was returned to the aeration tank. The...Based on the hypothesis of reducing sludge production under cryptic growth conditions, ozone was used as cell lysis agent to treat excess sludge,and then the ozonated supernatant was returned to the aeration tank. The results show that COD and NH+4-N removal efficiencies in ozonation process were 87.96% and 84.42%, respectively. Meanwhile, a low excess sludge yield coefficient of 0. 113 ( g SS/g COD removed) was obtained. Compared with that of the control test, the process configuration decreased the excess sludge production by 51.3%.展开更多
基金supported by Beijing Municipal Commission of Education(No.Z161100004516015)the Open Project Program of Hebei Center for Ecological and Environmental Geology Research(No.JSYF-202304).
文摘As an energy and carbon saving process for nitrogen removal from wastewater,the partial nitrification and denitrification process(PN/D)has been extensively researched.However,achieving stable PNinmunicipalwastewater has always been challenging.In this study,a gel immobilized PN/D nitrogen removal process(GI-PN/D)was established.A 94 days pilot-scale experiment was conducted using real municipal wastewater with an ammonia concentration of 43.5±5.3mg N/L at a temperature range of 11.3–28.7◦C.The nitrogen removal performance and associated pathways,shifts in the microbial community as well as sludge yield were investigated.The results were as follows:the effluent TN and COD were 0.6±0.4mg/L and 31.1±3.8 mg/L respectively,and the NAR exceeding 95%.GI-PN/D achieved deep nitrogen removal ofmunicipalwastewater through stable PN without taking any othermeasures.The primary pathways for nitrogen removal were identified as denitrification,simultaneous nitrification-denitrification,and aerobic denitrification.High-throughput sequencing analysis revealed that the immobilized fillers facilitated the autonomous enrichment of functional bacteria in each reactor,effectively promoting the dominance and stability of the microbial communities.In addition,GI-PN/D had the characteristic of low sludge yield,with an average sludge yield of 0.029 kg SS/kg COD.This study provides an effective technical for nitrogen removal from municipal wastewater through PN.
文摘Domestic wastewater was treated by combined anaerobic biofilm aerobic membrane bioreactor(MBR) process, and part biomass in MBR was withdrawn to treat with ozone, then the ozonated sludge was returned to anaerobic inlet. In aerobic MBR, MLSS and DO were controlled at 3000—3500 mg/L and 0 8 mg/L respectively. Comparing the experimental results of two stages, it was noticed that ozonation did not affect the removal efficiency for organics but had a significant influence on the removals of NH 3 N and TN. During the ozonation period of two months, no excess sludge was wasted, and a zero sludge yield was obtained.
文摘Based on the hypothesis of reducing sludge production under cryptic growth conditions, ozone was used as cell lysis agent to treat excess sludge,and then the ozonated supernatant was returned to the aeration tank. The results show that COD and NH+4-N removal efficiencies in ozonation process were 87.96% and 84.42%, respectively. Meanwhile, a low excess sludge yield coefficient of 0. 113 ( g SS/g COD removed) was obtained. Compared with that of the control test, the process configuration decreased the excess sludge production by 51.3%.
