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Biomethane Production through Anaerobic Digestion of Lignocellulosic Biomass and Organic Wastes
Published in Sonil Nanda, Prakash K. Sarangi, Biomethane, 2022
Alivia Mukherjee, Biswa R. Patra, Falguni Pattnaik, Jude A. Okolie, Nanda Sonil, Ajay K. Dalai
Sustainable energy generation from alternate and renewable energy sources is a subject widely discussed both in public forums and academic spaces because of the unremitting development of countries. The need for the diversification and expansion of sustainable energy is increasing because of the depletion of fossil fuel, the growing unsustainability of the old-linear economy coupled with the threat of climate change due to greenhouse gas (GHG) emissions. In this regard, anaerobic digestion (AD) has become a promising approach to produce biomethane from virtually all diverse biogenic solid wastes. It is gaining attention due to several noteworthy merits including the use of abundantly available bioresources, clean energy production, reduced greenhouse gas emission, applicability in remote areas, and widespread domestic applications of biomethane over conventional nonrenewable sources (Moghaddam et al., 2019; Oechsner et al., 2015; Angelidaki et al., 2011). Anaerobic digestion, one class of a biochemical process executed in the absence of oxygen in a closed digester or sealed lagoon, in which lignocellulosic rich organic substrates are mediated by a microbial consortium to produce biogas and digestate (Mittal et al., 2018; El-Mashad, 2013). The exploitation of biogas and the digestate further as a renewable source of energy and biofertilizer has gained attention in recent years (Shetty et al., 2020; Pellera and Gidarakos, 2018).
Aerobic and Anaerobic Degradation Pathways of PHA
Published in Martin Koller, The Handbook of Polyhydroxyalkanoates, 2020
Jorge A. Ferreira, Dan Åkesson
Biological degradation can include home and industrial composting, as well as biogas plants operated under aerobic and anaerobic conditions, respectively. These are two established technologies with a huge impact on the reduction of the organic portion of the municipal solid waste (e.g., food waste) [6]. Composting results in carbon dioxide, water, and a remaining soil-like material (humus) known as compost, while anaerobic digestion converts waste mainly into methane and also into a solid-like material known as digestate. Both the compost and the digestate, depending on the composition, can be used as fertilizers [6], while biogas (a mixture of mainly methane and carbon dioxide) can be used as a transportation fuel or for cooking, heat, and electricity [15]. Thus, biogas-producing processes can potentially have a higher contribution to energy security goals in comparison to that of composting. Due to their present industrial establishment, it becomes clear that the relevance of composting and anaerobic digestion for degradation of plastic waste will depend on the production of materials that can be degraded within the same timeframe (that is, retention time) as for the organic fraction of the municipal solid waste.
Innovative Bioelectrochemical-Anaerobic Digestion Coupled System for Process Monitoring Optimization and Product Purification of Wastewater
Published in Sonia M. Tiquia-Arashiro, Deepak Pant, Microbial Electrochemical Technologies, 2020
Yifeng Zhang, Xiangdan Jin, Mingyi Xu, Rusen Zou
AD process, a complex biological process in which microorganisms convert diverse wastes into biogas in the absence of oxygen, has been widely applied for simultaneous biogas production and wastewater treatment. Energy from waste biomass is regarded as one of the most dominant future renewable energy sources (Appels et al. 2011). Therefore, the application of AD has received increasing attention in recent decades due to its beneficial properties including: (i) various types of biomass and waste are suitable as substrates, and co-digestion brings superior efficiencies in most cases; (ii) the digestate is nutrient rich and can be utilized in agriculture or organic amendment; (iii) carbon-neutral process without greenhouse gas emissions; (iv) it is feasible in both large-scale industrial facilities and small-scale ones which are easy to be installed in rural areas.
Kinetics of combined hydrothermal pretreatment and anaerobic digestion of lignocellulosic biomass (pepper plant and eggplant)
Published in Environmental Technology, 2023
K. Hamraoui, J. A. Siles, A. F. Chica, M. A. Martín, H. El Bari
Anaerobic digestion is a biological process in which organic matter is mainly transformed into a set of gaseous products, or biogas, which is formed by CH4 (50–75%), CO2 (25–50%), H2(5–10%), H2S (traces)and other compounds, as well as into digestate, which is a mixture of mineral substances (N, P, K, Ca, etc.) and difficult-to-degrade compounds. This process takes place in the absence of oxygen through the action of a complex group of microorganisms [1] and is carried out globally in four steps: hydrolysis, acidogenesis, acetogenesis and methanogenesis. Hydrolysis is generally the rate-limiting step and consists of the release of extracellular bacterial enzymes that break down and further solubilize organic particulate matter to be used as substrate in subsequent reactions [2]. Therefore, one solution to enhancing degradation kinetics and digestion efficiency is to break the complex chemical bonds in the substrate before hydrolysis. Thus, pretreatment would not only be ideal but in some cases also necessary to disrupt the lignocellulose structure of the waste and increase its anaerobic digestibility.
Novel resources recovery from anaerobic digestates: Current trends and future perspectives
Published in Critical Reviews in Environmental Science and Technology, 2022
Paul Sebastian Selvaraj, Kalaiselvi Periasamy, Kathirvel Suganya, Kavitha Ramadass, Selvamurugan Muthusamy, Poornima Ramesh, Richard Bush, Salom Gnana Thanga Vincent, Thava Palanisami
The AD processes are presented in Figure 1. Large capacity AD plants cannot effectively manage large quantities of digestate since this process requires large-scale secure storage, transport, marketing according to the regulatory frameworks in place. Digestate consists of both the microbial biomass and undigested material. Most of the AD units generate approximately 85% of the feedstock volume as digestate, and the digestate is subjected to screw press or decanter centrifuge. It separates into solid (10%–20% by mass) and liquid (80%–90% by mass) fractions (Fuchs & Drosg, 2013). This stable solid digestate is easy to transport and store, and can subsequently be employed as an organic fertilizer in agriculture; it also has much potential as a precursor for many value-added materials, i.e., fuels, pyrochar, nanocellulose (Monlau, Sambusiti, Ficara, et al., 2015).
Determinants of functional status of family size bio-digesters: empirical evidence from southern Ethiopia
Published in International Journal of Sustainable Energy, 2019
Biogas is a combustible gas that is mainly composed of methane (60–70%) and carbon dioxide (30–40%) (Kumar et al. 2011). Biogas is produced in anaerobic bio-digesters, which have a variety of designs and applications, ranging from small to large-scale operations. The anaerobic process involves the biological degradation of organic waste that produces both a nutrient-rich digestate as well as biogas. Anaerobic digestion consists of several interdependent, complex, sequential and parallel biological reactions that occur in the absence of oxygen. During this process, the products from one group of microorganisms serve as food for the next, resulting in the transformation of biomass, mainly into a mixture of methane and carbon dioxide (Mwirigi et al. 2014), which are major constituents of biogas. During the anaerobic digestion, a large number of active hydrolytic and acid-forming acidogenic bacteria, acting in concert, utilise organic substrates such as carbohydrates, proteins and lipids produce volatile fatty acids by acidogenesis, which are later converted to methane and carbon dioxide by methanogenic bacteria through methanogensis (Bond and Templeton 2011).