Search

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 ...

In this study, the anaerobic treatment and microbial characteristics of high-concentration corn alcohol wastewater were studied by using a self-designed anaerobic expanded granular sludge bed (EGSB...

Oxytetracycline is one of the tetracycline antibiotics for feeding pig or cow, tetracycline antibiotics are the most widely used in animals and veterinary medicine as growth promoters and antibacte...

This study aimed to evaluate the hydrolysis of rapeseed oil using pyrrolidonium ionic liquids as catalysts under atmospheric pressure. The process parameters were optimized using a sequence...

Microbial electrolysis cell coupled anaerobic digestion (MEC-AD) is a new technology in energy recovery and waste treatment, which could be used to recycle swine manure. Here, different applied voltage effects were studied using MEC-AD with swine manure as a substrate. The maximum cumulative biogas and methane yields, both occurring with 0.9 V, were 547.3 mL/g total solid (TS) and 347.7 mL/g TS, respectively. The increased energy can counterbalance the electrical input. First order, logistic, gompertz, and back-propagation artificial neural network (BP-ANN) models were used to study cumulative biogas and methane yields. The BP-ANN model was superior to the other three models. The maximum degradation rate of hemicellulose, cellulose, and lignin was 60.97%, 48.59%, and 31.59% at 0.9 V, respectively. The BP-ANN model establishes a model for cumulative biogas and methane yields using MEC-AD. Thus, MEC-AD enhanced biogas and methane production and accelerated substrate degradation at a suitable voltage.

To avoid wastage of water resources and operating cost increases caused by the traditional start-up process of large amounts of dilution influent chemical oxygen demand (COD), a novel start-up process (NSP) was developed and verified with water hyacinth juice (WHJ) on an up-flow anaerobic sludge blanket (UASB) and modified internal circulation (MIC) reactor. Results show that UASB and MIC reactors were started successfully and that the MIC reactor exhibited a superior performance. The NSP time of the MIC reactor (46 days) was less than that of the UASB reactor (52 days), although the start-up organic loading rate (OLR) of the MIC reactor was higher than that of the UASB reactor. Interestingly, high-throughput sequencing analysis indicated that the reactor configuration significantly impacted the microbial diversity, however, the UASB and MIC reactors had similar predominant methanogens: Methanosaeta and Methanosarcina. Therefore, acetoclastic methanogenesis is the primary pathway of methane formation during WHJ treatment.

Lao PDR lacks of conventional energy resources, such as oil and natural gas, and 100% of fossil fuels are imported from abroad. Fossil fuel consumption in Lao PDR in 2010 was about 561 million lite...

Anaerobic digestion is one the most efficient technologies in waste and wastewater management for producing renewable energy and reducing greenhouse gas emission from animal manure. In this...

To improve the low energy production efficiency of fermentative hydrogen production (FHP) and fermentative methane production (FMP), the two types of fermentation were effectively combined in this study. Using sucrose as feedstock, both successive fermentative production of hydrogen followed by methane (SFPHM) and successive fermentative production of methane followed by hydrogen (SFPMH) were performed to improve the energy production efficiency of the overall anaerobic process. The results showed that the energy conversion efficiency of SFPHM was 79.85% whereas that of SFPMH was only 43.12%. Therefore, SFPHM can significantly improve the energy production efficiency of traditional anaerobic biological treatment.

The objective of this study was to investigate and evaluate the biomethane potential (BMP) of Bougainvillea spectabilis Willd (BSW) waste in Yunnan, China, when subjected to mesophilic anaerobic digestion (AD). Three different categories of plant waste investigated were as follows: the flowers, leaves, and stems. These three portions were assessed for their BMP in a laboratory-scale batch anaerobic digester for a period of 60 days at 30 ± 0.1°C temperature. The results showed that the maximum daily methane yield of B. spectabilia’s flowers, leaves, and stems were 65.95, 56.29, and 18.8 mL/(g﹒VS), respectively. The Gompertz equation presented the best agreement in the fitting progress.

Thermophilic anaerobic digestion (AD) coupled with the pretreatment was used as an alternative method for animal by-product disposal and energy recovery. In this study, the results showed that the cumulative biogas production in T121 thermal pretreatments was slightly lower than that in the Control, while there were no significant differences in the methane content produced between the treatments. Pretreatments with H2SO4 at all different concentrations inhibited the anaerobic digestion with lower biogas and methane production due to the high contents of total volatile fatty acids accumulated in the systems. High throughput sequencing analysis showed that pretreatments affected the diversity, community structure and composition of microbial consortia. However, all these treatments harboured the same dominant phylum (Firmicutes) and genus (Coprothermobacter) with active roles during the AD process. These results also suggested that different pretreatments could form their distinct methanogen pathways. Of the treatments, T121 pretreatment increased the relative abundance of methane-producing archaea. The abundance of Methanosarcina was dominated in the thermal pretreatments, suggesting the acetoclastic methanogenesis pathway of methane produced in thermal pretreatments. The abundances of Methanosarcina and Methanothermobacter were nearly the same in the Control and HS4 treatments respectively, indicating that both hydrogenotrophic and acetotrophic methanogen pathways were involved in the HS4 and control treatments. Considering other advantages of pathogen inactivation on pig mortalities, our study could be helpful for the disposal and further optimization of the higher energy recovery of animal carcasses by thermophilic AD coupled with thermal (121 °C) pretreatments.