Research On The Microaerobic Biofilter For Simultaneous Denitrification And Desulfurization And The Corncob Carbon Source In Liquid Phase

Nitric oxide?NO?and sulfur dioxide?SO₂?are the main pollutants that cause atmospheric environmental problems.Industrial boiler flue gas emission is the main source.Flue gas denitrification and desulfurization is one of the important ways to control air pollution.More and more attention has been paid to the flue gas denitrification and desulfurization with biological technology.In this paper,a new method of microbial simultaneous removal of NO and SO₂under thermophilic?48±2°C?micro-oxygen?3 vol%?conditions was proposed.The removal efficiency of NO and SO₂,degradation pathway and sulfur conversion efficiency of the biofilter were studied.At the same time,the diversity of microbial population structure and the interaction between functional microbial in different reaction stages were analyzed by high-throughput sequencing technology.Based on the consideration of economy and safety,we explored the feasibility of corncob as an external carbon source for microbiological simultaneous denitrification and desulfurization.The static release properties of corncob,acid treated corncob and alkali treated corncob were studied,and we investigated the efficiency of microbial denitrification and desulfurization with corncob as carbon source,to provide a theoretical basis for the industrialization of flue gas microbial denitrification and desulfurization technology.?1?The efficiency of a biofilter to simultaneously remove nitric oxide?NO?and sulfur dioxide?SO₂?was investigated under thermophilic?48±2°C?micro-oxygen?3 vol%?conditions.After the start-up phase?Days 0-14?,the stable operation period included three phases.The inlet concentration of SO₂remained 500 mg/m³,and NO inlet concentrations were 300 mg/m³?Days 15-40?,500 mg/m³?Days 41-70?and 700 mg/m³?Days 71-100?,respectively.At the end of each stable operation phase,the removal efficiency of NO and SO₂exceeded 90%,and the maximum removal efficiency of NO and SO₂were 98.08%and99.61%,respectively.The final products of SO₂were mostly sulphur?S⁰?.There was a competitive relationship between nitrate-reducing bacteria?NRB?and sulfate-reducing bacteria?SRB?.NRB had a certain inhibitory effect on SRB.Micro-oxygen condition could alleviate this inhibitory effect.High-throughput sequencing results showed that the relative abundance of NRB was positively correlated with the removal efficiency of NO,and the relative abundance of SRB was related to the conversion rate of S⁰.?2?Taking corncob as the research object,we studied the feasibility of microbiological simultaneous denitrification and desulfurization with corncob as external carbon source under micro-oxygen condition?0.1?0.2 mg/L DO?.The corncob was respectively pretreated with1%H₂SO₄,2%H₂SO₄,4%H₂SO₄,1%Na OH,2%Na OH,4%Na OH,the untreated corncob was used as a control to perform corncob static release experiments.Compared with untreated corncob,the COD release rate of acid treated corncob and alkali treated corncob was higher,and pretreated corncob released more carbon and nitrogen.Glucose,untreated corncob,1%H₂SO₄treated corncob and 2%Na OH treated corncob were used as external carbon sources for simultaneous denitrification and desulfurization experiments under micro-oxygen condition.Compared the three groups of corncob treated with different methods,we found that corncob could be used as an carbon source for microbiological simultaneous denitrification and desulfurization under micro-oxygen condition.2%Na OH treated corncob not only had stronger long-term stable carbon release capacity,but also had the best denitrification and desulfurization performance.