Innovative nitrate removal process for low organic carbon wastewater based on iron-carbon micro-electrolysis
Nitrate removal by heterotrophic denitrifiers is widely applied in wastewater treatment;however,it necessitates sufficient organic carbon.Here,an innovative nitrate removal process was developed for wastewater with a low chemical oxygen demand (COD)/total nitrogen (N) ratio.Employing iron-carbon micro-electrolysis carriers (IC-MECs) developed by our group,H2 and Fe2+ generated from galvanic reactions were used by autotrophic denitrifying bacteria as inorganic electron donors,and bicarbonate were used as inorganic carbon sources.Two continuous reactors were operated for 168 days at 24 ± 1℃,and the NO3-N in influent was kept at ~ 40 mg/L.When HRTs were 12h,the results showed a high TN removal efficiency > 90% for simulated wastewater with a low COD/N ratio (~ 40 mg COD/L);and TN removal efficiency achieved 85% for organic-free simulated wastewater.As a contrast,the third reactor was operated under similar conditions,using zeolite carriers instead of IC-MECs.TN removal efficiency was only 20% under the low COD/N ratio (~ 40 mg COD/L),and reached >90% when COD in influent increased to 200 mg/L.To reveal the microbial communities in reactors,high-thought sequencing was applied.The results showed that Thiobacillus (27.0%) and Rubellimicrobium (7.5%),which represent autotrophic denitrifiers,were the most abundant genera under organic-free conditions;meanwhile,Zoogloea (16.6%),Silanimonas (12.8%) and Thauera (10.8%),which represent heterotrophic denitrifiers,were the top three genera on zeolite carriers;in addition,Thauera (11.2%) was also detected as a dominant genus on the surface of IC-MECs with organics provided as 40 mg COD/L.These findings indicated that autotrophic denitrification played a very important role in this novel nitrate removal process,and autotrophic and heterotrophic denitrification were combined together to achieve a higher TN removal efficiency under low COD/N ratio.This process facilitates nitrate removal from wastewater with insufficient organic carbon.
Denitrification autotrophic micro-electrolysis microbial community high-thought sequencing
Wei XING Desheng LI Jinlong LI Shihai DENG
Department of Municipal & Enironmental Engineering, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
210-214
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）