Liquid co-substrates repower sewage microbiomes

Abstract

A range of parameters are known to shape the methanogenic communities of biogas-producing digesters and to strongly influence the amount of biogas produced. In this work, liquid and solid fractions of grass biomass were used separately for semicontinuous batch methanation using sewage sludge as seed sludge. During 6 months of incubation, the amount of input COD was increased gradually, and the underlying methanogenic microbiome was assessed by means of microscopy-based automated cell counting and full-length 16S rRNA high-throughput sequencing. In this sense, we prove for the first time the suitability of the ONT TM MinION platform as a monitoring tool for anaerobic digestion systems. According to our results, solid-fed batches were highly unstable at higher COD input concentrations, and kept Methanosaeta spp. -typically associated to sewage sludge-as the majoritary methanogenic archaea. In contrast, liquid-fed batches developed a more stable microbiome, and proved enriched in Methanosarcina spp. This work demonstrates the high repowering potential of microbiomes from sewage sludge digesters, and highlight the effectiveness of liquefied substrates for anaerobic digestions.

Monitoring of seven industrial anaerobic digesters supplied with biochar

“…2). In general, the detected concentration of methanogenic archaea was in a similar range as in other studies [15,16]. Interestingly, the number of methanogenic archaea seemed to decrease slightly throughout time upon the addition of biochar.…”

“…An epifluorescent microscope (Axio Lab.A1, Carls Zeiss, Germany) was used to quantify cofactor F420 as an indirect measure of methanogenic archaea load. The methodology was similar to a recent study from Hardegen et al [15]. Excitation occurred with wavelengths ranging from 400 to 440 nm.…”

The influence of microbial community dynamics on anaerobic digestion efficiency and stability: A Review

“…Although AD has been subjected to substantial process engineering, the underpinning microbial community has been treated largely as a 'black box' and presents a significant opportunity for additional optimisation. Fortunately, rapid development in sequencing technology (nextgeneration sequencing (NGS)) that can provide more comprehensive information at a much cheaper cost, making it easier for researchers to identify and understand not only community composition and their metabolic functions but also how operational conditions (such as type of feedstock and temperature) influence microbial system (structure and dynamics) that can be linked to AD performance efficiency and stability (Talbot et al 2008;Nelson, Morrison and Yu 2011;Wilkins et al 2015;Bocher et al 2015;De Vrieze et al 2017;De Vrieze et al 2018;Kirkegaard et al 2017;Hardegen et al 2018). Each stage in anaerobic digestion is carried out by different microbial groups, and its composition in the consortium depends on several factors, such as the type of substrate, temperature, pH, mixing and applied digester geometry (Yu and Mohan 2001;Insam et al 2010;Francisci et al 2015;Nathia-Neves et al 2018).…”

How Urban Storm- and Wastewater Management Prepares for Emerging Opportunities and Threats: Digital Transformation, Ubiquitous Sensing, New Data Sources, and Beyond - A Horizon Scan

“…For urban drainage systems, eDNA could improve identifying illicit connections in stormwater systems − by tracking fecal pollution from humans, or closely monitor combined sewer discharges at an unprecedented temporal resolution. For WWTPs, profiling entire microbial communities could lead to gain better insight into relevant processes, for example, bulking and foaming, digester performance, or the behavior of viruses. , For receiving waters, eDNA can be useful through the spatial integration of point samples and the possibility to perform biomonitoring and chemical analysis on the same water sample. This would greatly improve tracking the impact of pollutant discharges or change in aquatic species .…”

“…This would greatly improve tracking the impact of pollutant discharges or change in aquatic species . The development of portable and real-time capable instruments could even open up next generation compliance schemes and inform novel conservation strategies …”