Zhikun Lu, Yifeng Xu, Chuanzhou Liang, Wenshan Guo, Huu Hao Ngo, Lai Peng
{"title":"Biogenic sulfide by sulfur disproportionation enhances nitrate removal and reduces N<sub>2</sub>O production during sulfur autotrophic denitrification.","authors":"Zhikun Lu, Yifeng Xu, Chuanzhou Liang, Wenshan Guo, Huu Hao Ngo, Lai Peng","doi":"10.1016/j.chemosphere.2024.143915","DOIUrl":null,"url":null,"abstract":"<p><p>Sulfur autotrophic denitrification (SADN) is regarded as a cost-effective bioremediation technology for nitrate-contaminated water. Nevertheless, the low bioavailability of sulfur is a major challenge that hinders nitrogen removal efficiency. A sulfur autotrophic disproportionation (SADP) process was proposed to convert sulfur to biogenic sulfide, greatly increasing the availability of electron donors. Throughout the 201-day laboratory-scale test, it was observed that the SADP process achieved desirable performance with 198.87 ± 39.8 mg S/L biogenic sulfide production per day, which could provide sufficient electron donors for the SADN process in treatment of 671.22 ± 134.40 mg N/L/d nitrate. Microbial community analysis confirmed the presence and dominancy of sulfur-disproportionating bacteria (SDB) (e.g., Desulfocaspa sp. taking up to 8.27% of the entire microbial community), while Thiobacillus was the most dominant genus of sulfur oxidizing bacteria (SOB), accounting for 87.32% of the entire community. Further experiments revealed that the addition of chemical and biogenic sulfides enhanced the nitrate removal rate of the SADN process by a factor of 1.31 and 1.34, respectively. Additionally, biogenic sulfide was found to be the most effective nitrous oxide (N<sub>2</sub>O) mitigator, reducing emission by 82% and 95% in denitrification and denitritation processes, respectively. The results demonstrated that the integrated SADP and SADN processes was a more effective and carbon-neutral alternative in treatment of nitrate-contaminated water.</p>","PeriodicalId":93933,"journal":{"name":"Chemosphere","volume":" ","pages":"143915"},"PeriodicalIF":0.0000,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemosphere","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1016/j.chemosphere.2024.143915","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Sulfur autotrophic denitrification (SADN) is regarded as a cost-effective bioremediation technology for nitrate-contaminated water. Nevertheless, the low bioavailability of sulfur is a major challenge that hinders nitrogen removal efficiency. A sulfur autotrophic disproportionation (SADP) process was proposed to convert sulfur to biogenic sulfide, greatly increasing the availability of electron donors. Throughout the 201-day laboratory-scale test, it was observed that the SADP process achieved desirable performance with 198.87 ± 39.8 mg S/L biogenic sulfide production per day, which could provide sufficient electron donors for the SADN process in treatment of 671.22 ± 134.40 mg N/L/d nitrate. Microbial community analysis confirmed the presence and dominancy of sulfur-disproportionating bacteria (SDB) (e.g., Desulfocaspa sp. taking up to 8.27% of the entire microbial community), while Thiobacillus was the most dominant genus of sulfur oxidizing bacteria (SOB), accounting for 87.32% of the entire community. Further experiments revealed that the addition of chemical and biogenic sulfides enhanced the nitrate removal rate of the SADN process by a factor of 1.31 and 1.34, respectively. Additionally, biogenic sulfide was found to be the most effective nitrous oxide (N2O) mitigator, reducing emission by 82% and 95% in denitrification and denitritation processes, respectively. The results demonstrated that the integrated SADP and SADN processes was a more effective and carbon-neutral alternative in treatment of nitrate-contaminated water.