Alkaline fermentation of refinery waste activated sludge mediated by refinery spent caustic for volatile fatty acids production

Jin Li; Wenzhuo Xin; Jiahao Liang; Pengyin Shang; Yanke Song; Qinghong Wang; Mohamed Gamal El-Din; Muhammad Arslan; Shaohui Guo; Chunmao Chen

doi:10.1016/j.jenvman.2022.116317

Alkaline fermentation of refinery waste activated sludge mediated by refinery spent caustic for volatile fatty acids production

J Environ Manage. 2022 Dec 15:324:116317. doi: 10.1016/j.jenvman.2022.116317. Epub 2022 Sep 28.

Authors

Affiliations

¹ State Key Laboratory of Petroleum Pollution Control, Beijing Key Laboratory of Oil and Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
² Guangdong Provincial Key Laboratory of Petrochemical Pollution Process and Control, Key Laboratory of Petrochemical Pollution Control of Guangdong Higher Education Institutes, School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming, Guangdong, 525000, China.
³ State Key Laboratory of Petroleum Pollution Control, Beijing Key Laboratory of Oil and Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China. Electronic address: wangqhqh@163.com.
⁴ Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.

PMID: 36182845
DOI: 10.1016/j.jenvman.2022.116317

Abstract

Volatile fatty acids (VFA), produced from waste activated sludge (WAS), provide unique opportunities for resource recovery in wastewater treatment plants. This study investigates the potential of refinery spent caustic (RSC) on VFA production during refinery WAS (RWAS) alkaline fermentation. The highest VFA yield was 196.3 mg/g-VS at a sludge retention time of 6 days. Amplicon sequencing revealed the enrichment of Soehngenia (20.21%), Bacilli (11.86%), and Brassicibacter (4.17%), which was associated with improved activities of protease (626%) and α-glucosidase (715%). Function prediction analysis confirmed that acetyl-CoA production and fatty acid biosynthesis were enhanced, while fatty acid degradation was inhibited. Accordingly, hydrolysis, acidogenesis, and acetogenesis were improved by 6.87%, 10.67%, and 28.50%, respectively; whereas methanogenesis was inhibited by 28.87%. The sulfate and free ammonia in RSC likely contributed to increased acetic acid production. This study showcases that RWAS alkaline fermentation mediated by RSC for VFA production is the practicable approach.

Keywords: Alkaline fermentation; Refinery spent caustic; Volatile fatty acids; Waste activated sludge.

MeSH terms

Bioreactors
Caustics*
Fatty Acids, Volatile / metabolism
Fermentation
Hydrogen-Ion Concentration
Sewage*

Substances

Sewage
Caustics
Fatty Acids, Volatile