Anaerobic digestion of chemically enhanced primary treatment (CEPT) sludge and the microbial community structure

Abstract

The effectiveness and treatment conditions of FeCl3- and AlCl3-coagulated municipal sewage sludge from chemically enhanced primary treatment (CEPT) using anaerobic digestion (AD) and the structure of microbial community were investigated. The results based on 297 measurements under different operational conditions demonstrate good average AD performance of CEPT sludge, that is, percent volatile solid reduction of 58 %, specific biogas production (or biogas yield) of 0.92 m(3)/kg volatile solids (VS) destroyed, and methane content of 65.4 %. FeCl3 dosing, organic loading rate, temperature, and hydraulic retention time all significantly affected AD performance. FeCl3 dosing greatly improved specific methane production (methane yield) by 38-54 % and significantly reduced hydrogen sulfide (H2S) content in biogas (from up to 13,250 to <200 ppm), contributing to higher methane recovery and simplified biogas cleaning for power generation. Metagenomic analysis suggested that anaerobic digesters of both CEPT sludge and combined primary and secondary sludge were dominated by Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria, Thermotogae, and Chloroflexi. However, Methanomicrobia methanogens were better enriched in the anaerobic digesters of CEPT sludge than in the combined sludge. Further, different sources of CEPT sludge with various chemical properties nurtured shared and unique microbial community composition. Combined, this study supports AD as an efficient technology for CEPT sludge treatment and poses first insights into the microbial community structure.

Unraveling the Microbial Interactions and Metabolic Potentials in Pre- and Post-treated Sludge from a Wastewater Treatment Plant Using Metagenomic Studies

“…Studies that decipher the community composition of anaerobic sludge has also been conducted by many research groups across the world (Guo et al, 2015; Sun et al, 2015; Ferrentino et al, 2016; Ju et al, 2016) but the studies conducting the detailed investigation of taxonomic as well as functional composition of pre- and post-treated anaerobic sludge are very few. Researchers have used different sequencing depths ranging from 0.1 GB to 3.3 GB to study functional composition using the Ion-torrent platform (Joshi et al, 2014; Patel et al, 2014; Rua et al, 2015; Hinsu et al, 2017; Motooka et al, 2017).…”

Microbial community dynamics and functional responses that contribute to tolerance of high concentrations of petroleum hydrocarbon

“…Recently, AS has been successfully applied in the remediation of PH pollution and has shown great advantages . However, the types and concentrations of PH as well as the structure and function of the microbial community have always been the main factors which limit the efficiency of PH remediation using AS.…”

“…20,21 Recently, AS has been successfully applied in the remediation of PH pollution and has shown great advantages. 22,23 However, the types and concentrations of PH as well as the structure and function of the microbial community have always been the main factors which limit the efficiency of PH remediation using AS. Therefore we used AS to degrade different concentrations of PH and investigated the degradation rate of PH and the change of bacterial community structure during the process.…”

Utilization of Ultraviolet-Visible Spectroscopy and Rheology for Sludge Characterization and Monitoring

“…They found that the anaerobic digestion achieved 32% VSR while the aerobic digestion achieved an additional 17%, indicating an improvement in the level of treatment from the conventional anaerobic digestion process (Tomei et al, 2011). Ju et al (2016) also used VSR as one of the parameters to monitor the performance of the anaerobic digestion of chemically enhanced primary treatment sludge compared to secondary sludge, consisting of mixed thickened primary sludge and thickened secondary activated sludge. From their study, they could conclude that anaerobic digestion of chemically enhanced primary treatment sludge was more effective than that of combined sludge as the VSR was found to be 54% and 36%, respectively (Ju et al, 2016).…”

“…Ju et al (2016) also used VSR as one of the parameters to monitor the performance of the anaerobic digestion of chemically enhanced primary treatment sludge compared to secondary sludge, consisting of mixed thickened primary sludge and thickened secondary activated sludge. From their study, they could conclude that anaerobic digestion of chemically enhanced primary treatment sludge was more effective than that of combined sludge as the VSR was found to be 54% and 36%, respectively (Ju et al, 2016). Once this was demonstrated, they then used VSR as a parameter to evaluate variations in key operational parameters such as ferric chloride dose, temperature, salinity and hydraulic retention time (HRT) during the anaerobic digestion of the chemically enhanced primary treatment sludge.…”