Volatile fatty acids bio-production using extracellular polymeric substances disengaged from sludge for carbon source recycling

• Published in: Bioresource technology 2023-10, Vol.386, p.129565-129565, Article 129565
• Main Authors: Li, Xiqi, Yu, Zhe, Ge, Xiaoli, Zhang, Wenzhe, Fang, Yingke, Liu, Wenzong, Wang, Aijie
• Format: Article
• Language: English
• Subjects: carbon; denitrification; dewatering; Extracellular polymeric substances; fermentation; flora; Interspecific interaction network; Microbial community; nitrogen; polymers; Resource recovery; sewage treatment; sludge; Volatile fatty acids
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129565

[Display omitted] •EPS disengagement from sludge can be achieved via combined LTH&HSHC pretreatment.•VFAs bio-production using EPS performs efficiently in thermophilic fermentation.•The microbial mechanisms for rapid bio-conversion of EPS into VFAs are disclosed.•The novel strategy is promising to recycle CS while avoiding the dewatering deterioration. Excessive waste-activated sludge (WAS) and insufficient carbon source (CS) for biological nitrogen removal (BNR) often coexist in municipal sewage treatment. Although the production of volatile fatty acids (VFAs) from WAS has been recognized as a promising solution, the development is limited by low VFAs production efficiency and dewatering deterioration of sludge. This study extracted the extracellular polymeric substances (EPS) from sludge by low-temperature thermal-hydrolysis (LTH) and high-speed hydro-cyclone (HSHC) pretreatment and recovered it for high-quality VFAs bio-production in thermophilic fermentation. Microbial mechanism analysis disclosed that interspecific interaction networks composed of functional flora, which accumulate VFAs by bio-converting EPS primarily and supplemented by EPS synthesis, guaranteed the efficient bio-production of VFAs. This process scheme shows promise in providing alternative denitrification CSs and avoiding deterioration of sludge dewaterability.