Insights into microbial interaction profiles contributing to volatile fatty acids production via acidogenic fermentation of waste activated sludge assisted by calcium oxide pretreatment

This first-attempted study illustrated the calcium oxide (CaO) agentia-pretreatment for prompting waste activated sludge (WAS) solubilization and enhancing volatile fatty acids (VFAs) bio-production through acidogenic fermentation. The 15-h CaO pretreatment was capable to produce a soluble chemical oxygen demand (SCOD) yield of ca. 153.17 mg COD/g VS and VFAs generation efficiency of 327.8 mg COD/g VS with adding dosage of 0.07 g/g TS. The relative frequencies corresponded to metabolic functions profiling were promoted obviously by CaO pretreatment and contributed to biosolid decomposition/VFAs production in sludge fermentation. Main genera of Azonexus, Arcobacter, Acinetobacter, Thauera, Petrimonas, Clostrium and Macellibacteroides cooperated synergically toward triggering concurrent VFAs generation/biosolid biodegradation. Finally, the CaOpretreatment displayed positive merits in terms of sludge biosolid decomposition/recoverable resource harvest as compared with other alkali pretreatments. This study might shed lights on enriching intensification strategy for WAS management toward high-efficiency of recoverable resource harvest with lower cost.