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An expanded granular sludge bed (EGSB) and modified continuous stirred tank reactor (MCSTR) were investigated with respect to the treatment of water hyacinth juice (WHJ) and water hyacinth residue (WHR), to promote the utilisation of water hyacinth as a resource and control its excessive growth. The results revealed that EGSB and MCSTR can efficiently manage WHJ and WHR. The energy recovery efficiency of water hyacinth was 21.10 m3 biogas/t, wherein the WHJ in EGSB produced 0.190 m3 biogas/kg chemical oxygen demand, and the WHR in MCSTR generated 397 mL biogas/g total solid. High-throughput sequencing analyses indicated that the MCSTR and EGSB had similar dominant microbial composition in the hydrolytic acidification phase, while genus norank_o__NB1-n was unique to the MCSTR. The methanogenesis metabolic pathways of WHR contained both acetoclastic methanogenesis and hydrogenotrophic methanogenesis, where the dominant functional microorganisms were Methanosaeta and Methanobacterium, respectively. However, the methanogenetic metabolic pathways of WHJ involved only acetoclastic methanogenesis, with Methanosaeta as the dominant functional microorganism. A novel processing technology for the sustainable utilisation of water hyacinth was successfully established. This technology allowed for substance circulation and energy exchange in the ecosystem and is suitable for industrial applications owing to its performance, cost, and environment-friendly characteristics.

One of the problems faced by the world today is the management of all types of waste and energy crisis. The rapid growth of population, uncontrolled and unmonitored urbanization has created various...

Vegetable waste has a high biodegradation ability and moisture content and causes soil and underground water pollution. High moisture vegetable waste could be separated into juice and residual mate...

Spreng is an invasive weed and an abundant carbon resource threatening the safety of ecosystems and humans. We evaluated hot water immersion (HWI) pre-treatment of E. adenophorum to produce biogas ...

The main objective of this study was to establish the metabolic pathway of a biogas fermentation system active at low temperature, and to describe the bacterial and archaeal methanogenic species responsible. A biogas fermentation inoculum adapted to be active at 9°C was used in a 10‐L batch‐type temperature‐controlled fermentor, using pig manure as the raw material. Fermentation at 9°C was followed for 120 days. A combination of nonbiological and biological factors was analyzed. Species were identified from OTU analysis based on 16S rDNA amplicon sequencing, and correlation analysis was used to study the effect of nonbiological factors, bacterial communities, and archaea communities. Biogas production was most effective between days 50 and 90, where gas production was above 0.70 L/d and the CH4 yield was above 0.36 L/g‐volatile solid. The relative abundance of the first dominant bacterial OTU with 99% identity to Clostridium cellulovorans varied between 16.17% and 27.30%. These bacteria typically degrade cellulose and hemicellulose. The second dominant bacterial OTU (relative abundance 15.23%‐27.15%) was 99% identical to Terrisporobacter petrolearius, a typical fermentative species. The most abundant (4.15%‐37.14%) archaeal OTU was 98% identical to Methanocorpusculum sinense, which is a typical hydrogenotrophic methanogen. A low‐temperature biogas metabolic pathway was constructed, based on abundant bacterial and methanogen OTUs. The most suitable metabolic pathway describes that hydrogen is produced by one part of the community and then used to reduce the produced carbon dioxide into CH4; this seems to be the major pathway by which biogas is produced under low‐temperature conditions.