Unveiling the mechanisms of how vivianite affects anaerobic digestion of waste activated sludge

Peracetic acid (PAA)-based pretreatment effectively improves medium-chain fatty acids (MCFAs) production from sewage sludge

“…As displayed in Fig. 1 d–h, two fluorescence peaks, peak 1 and peak 2, appear on the spectrogram, and their color reflects the changes in organic matter content [ 29 ]. The fluorescence intensity is enhanced by PAA pretreatment at all doses compared to the control, implying more soluble material release (Fig.…”

Enhanced anaerobic digestion of waste activated sludge with periodate-based pretreatment

“…It could be found that Firmicutes and Bacteroidota presented higher abundances in the experimental digester than that in the control (17.4% vs. 15.8% and 7.9% vs. 6.9%). These two phyla are capable of converting organics to SCFAs [ 27 ]. The improved biodegradability of WAS could be the important reason for the enrichment of Firmicutes phylum, which tends to utilize readily biodegradable organics (such as soluble polysaccharides and proteins) [ 42 , 43 ].…”

“…The changes in the microbial communities of the sludge samples from digesters (0 and 75 mg per g TS) after 50-day methanogenic fermentation were analyzed by 16S rRNA sequencing. Two primers were 515FmodF and 806RmodR [ 27 ]. To further expand our knowledge of the anaerobic digestion microbiome, the metabolic potential and functional pathways of microorganisms at the genetic level were predicted as complementary information of 16S RNA sequencing through the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) software based on KEGG (Kyoto Encyclopedia of Gene and Genome) pathway annotation [ 28 ].…”

Unravelling key factors controlling vivianite formation during anaerobic digestion of waste activated sludge

“…4c (the lower half) and Fig. 4d combined for analysis in the initial period of the tests (prior to 3 d), the rate of ferric bio-reduction in R 6 -R 10 was enough to be combined with already released PO 4 3at that time, indicating that soluble Fe 2+ increased and soluble PO 4 3dropped prior to 3 d Then, soluble Fe 2+ got down and soluble PO 4 3increased, revealing that more PO 4 3was released from bacterial cells (Wang et al, 2022) and the rate of ferric bio-reduction that emerged was insufficient to be combined with PO 4 3released for vivianite formation, till 5 d. In 5 d, the release of PO 4 3became slow and reduced Fe 2+ could be gradually combined with all released PO 4 3for vivianite formation in 2 d.…”