Sulfur cycle as an nitrate in a electron mediator between carbon and constructed wetland microcosm  

作　　者：Wenrui Guo Yue Wen Yi Chen Qi Zhou 

机构地区：[1]State Key Laboratory of Pollution Control and Resource Reuse,College of Environmental Science and Engineering,Tongji University,Shanghai 200092,China [2]Shanghai Institute of Pollution Control and Ecological Security,Shanghai 200092,China [3]Key Laboratory of the Three Gorges Region's Eco-Environment,Ministry of Education,College of Environment and Ecology,Chongqing University,Chongqing 400044,China

出　　处：《Frontiers of Environmental Science & Engineering》2020年第4期17-29,共13页环境科学与工程前沿（英文）

基　　金：This work was financially supported by the National Natural Science Foundation of China(Grant No.51578393).

摘　　要：A constructed wetland microcosm was employed to investigate the sulfur cycle-mediated electron transfer between carbon and nitrate.Sulfate accepted electrons from organics at the average rate of 0.84 mol/(m3·d)through sulfate reduction,which accounted for 20.0%of the electron input rate.The remainder of the electrons derived from organics were accepted by dissolved oxygen(2.6%),nitrate(26.8%),and iron(III)(39.9%).The sulfide produced from sulfate reduction was transformed into acidvolatile sulfide,pyrite,and elemental sulfur,which were deposited in the substratum,storing electrons in the microcosm at the average rate of 0.52 mol/(m3·d).In the presence of nitrate,the acid-volatile and elemental sulfur were oxidized to sulfate,donating electrons at the average rate of 0.14 mol/(m3•d)and driving autotrophic denitrification at the average rate of 0.30 g N/(m3·d).The overall electron transfer efficiency of the sulfur cycle for autotrophic denitrification was 15.3%.A mass balance assessment indicated that approximately 50%of the input sulfur was discharged from the microcosm,and the remainder was removed through deposition(49%)and plant uptake(1%).Dominant sulfatereducing(i.e.,Desulfovirga,Desulforhopalus,Desulfatitalea,and Desulfatirhabdium)and sulfuroxidizing bacteria(i.e.,Thiohalobacter,Thiobacillus,Sulfuritalea,and Sulfurisoma),which jointly flilfilled a sustainable sulfur cycle,were identified.These results improved understanding of electron transfers among carbon,nitrogen,and sulfur cycles in constructed wetlands,and are of engineering significance.

关 键 词：Constructed wetland Sulfur cycle Electron transfer DENITRIFICATION 

分 类 号：O62[理学—有机化学] X17[理学—化学]