Biogas

About: Biogas is a research topic. Over the lifetime, 28571 publications have been published within this topic receiving 498545 citations.

Siloxane removal from biogas by biofiltration: biodegradation studies

Abstract: Recently a lot of attention has been focused on volatile methyl siloxanes (VMSs) in biogas because of the costly problems deriving from the formation of silicate-based deposits in biogas-fuelled power plant equipments. Currently, VMSs are removed from biogas with high operational costs by adsorption on activated carbons. Biofiltration could be a cost-effective and environmentally friendly alternative to current technologies, leading to a decrease in the cost of biogas treatment, therefore enhancing its use for power generation. This document presents the results of biodegradation studies on VMSs aimed to investigate the possibility of using biofiltration to treat biogas. Growth of bacteria isolated from activated sludge with octamethylcyclotetrasiloxane (D4) in the vapour phase as the only carbon source was observed. 16S-rDNA-sequencing showed that the mixed population mainly contained γ-proteobacteria; within these, Pseudomonas was the dominating genus. A biotrickling filter was set up to treat different air flows with a siloxane concentration varying between 45 and 77 mg m−3. Measurements on the gas output revealed removal efficiency up to 20% compared to a control in sterile conditions.

Improvement of biogas production from orange peel waste by leaching of Limonene

Abstract: Limonene is present in orange peel wastes and is known as an antimicrobial agent, which impedes biogas production when digesting the peels. In this work, pretreatment of the peels to remove limonene under mild condition was proposed by leaching of limonene using hexane as solvent. The pretreatments were carried out with homogenized or chopped orange peel at 20–40°C with orange peel waste and hexane ratio (w/v) ranging from 1 : 2 to 1 : 12 for 10 to 300 min. The pretreated peels were then digested in batch reactors for 33 days. The highest biogas production was achieved by treating chopped orange peel waste and hexane ratio of 12 : 1 at 20°C for 10 min corresponding to more than threefold increase of biogas production from 0.061 to 0.217 m3 methane/kg VS. The solvent recovery was 90% using vacuum filtration and needs further separation using evaporation. The hexane residue in the peel had a negative impact on biogas production as shown by 28.6% reduction of methane and lower methane production of pretreated orange peel waste in semicontinuous digestion system compared to that of untreated peel.

Thermophilic Anaerobic Digestion of Solid Waste for Fuel Gas Production

Abstract: Anaerobic digestion offers a potential means of converting organic solid waste into fuel gas and thereby provide a supplemental and readily utilizable source of energy. We are particularly interested in the use of thermophilic digestion over a mesophilic operation for it can achieve higher rates of digestion, greater conversion of waste organics to gas, faster solid-liquid separation, and minimization of bacterial and viral pathogen accumulation. Our results comparing mesophilic (37 degree C) and thermophilic (65 degree C) anaerobic digestion of domestic solid waste confirm the increased rate and conversion of waste to methane. In addition, utilizing radioactive labeling of glucose and acetic acid, we have measured the volumetric rates of volatile acid production and disappearance under both mesophilic and thermophilic conditions.