Biogas production: current state and perspectives

Abstract

Anaerobic digestion of energy crops, residues, and wastes is of increasing interest in order to reduce the greenhouse gas emissions and to facilitate a sustainable development of energy supply. Production of biogas provides a versatile carrier of renewable energy, as methane can be used for replacement of fossil fuels in both heat and power generation and as a vehicle fuel. For biogas production, various process types are applied which can be classified in wet and dry fermentation systems. Most often applied are wet digester systems using vertical stirred tank digester with different stirrer types dependent on the origin of the feedstock. Biogas is mainly utilized in engine-based combined heat and power plants, whereas microgas turbines and fuel cells are expensive alternatives which need further development work for reducing the costs and increasing their reliability. Gas upgrading and utilization as renewable vehicle fuel or injection into the natural gas grid is of increasing interest because the gas can be used in a more efficient way. The digestate from anaerobic fermentation is a valuable fertilizer due to the increased availability of nitrogen and the better short-term fertilization effect. Anaerobic treatment minimizes the survival of pathogens which is important for using the digested residue as fertilizer. This paper reviews the current state and perspectives of biogas production, including the biochemical parameters and feedstocks which influence the efficiency and reliability of the microbial conversion and gas yield.

Using Chemically Enhanced Primary Treatment (CEPT) as a Pretreatment Option for Anaerobic Digestate from Cattle Manure Digestion System

“…One promising process for biological conversion of organic wastes is anaerobic digestion (AD), which turned wastes into renewable energy and biofuel in the form of methane. This method is arousing more interest because it has the ability to mitigate the impact of wastes on the environment and facilitate sustainable development [3,4]. AD is an effective biochemical process for organic waste treatment and for biogas production because AD offers numerous significant advantages, such as low sludge production, low energy requirement, and green energy recovery.…”

Anaerobic Mesophilic Codigestion of Rice Straw and Chicken Manure: Effects of Organic Loading Rate on Process Stability and Performance

“…Owing to the intrinsic characteristics of straw, including unbalanced nutritional properties such as the carbon/nitrogen ratio (C/N), its recalcitrant lignocellulosic structure, and its tendency to float in liquid fermentation reactors [3], numerous studies have focused on nutritional regulation [4], pretreatment [5], and improvement of fermentation processes [6]. Co-digestion is considered a more cost-effective method for nutritional regulation than addition of nitrogen-containing chemical reagents such as urea or ammonium bicarbonate.…”

Mineral CO2 sequestration by environmental biotechnological processes

“…half of the produced CO 2 is captured). Depending on the utilization pathway of the biogas, the increase in methane content can offer higher heat and power generation efficiency (Weiland, 2010). In addition, if olivine ((Fe,Mg) 2 SiO 4 ) is used as a source of divalent cation and alkalinity, the iron can facilitate mineralization of H 2 S as ferrous sulfide (FeS) (Schuiling, 2009).…”