Research Into Design and Modeling of Anaerobic Digestion Process Applied to Municipal Solid Wastes (original) (raw)
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This paper describes a methodological tool developed for the evaluation of different Anaerobic Digestion (AD) technologies for treating the Organic Fraction of Municipal Solid Waste (OFMSW). Several such technologies have been proposed over the last years; when compared to biogas recovery from landfills, their main advantage is the stability in biogas production and the stabilization of waste prior to final disposal, whereas biogas recovery from landfills has the main setback that it extends over a great time period and may show significant fluctuations on biogas quantity and quality. AD technologies also show great adaptability to a broad spectrum of different input material beside OFMSW (e.g. agricultural and animal wastes, sewage sludge) and can also be used in remote and isolated communities, either stand-alone or in conjunction to other renewable energy sources. AD technologies follow different approaches to the AD process and also can include production of compost; furthermore...
2016
Worldwide there is an increasing trend for the study and use of new sources of renewable energy. Municipal solid wastes are becoming increasingly used as an energy source in waste-to-energy projects. Anaerobic digestion (AD) is a mature technology for energy production by converting organic fraction of municipal solid waste (OFMSW) into biogas. For this purpose, there were approached fundamental aspects of AD, the types of digesters and the performance of anaerobic treatment systems of OFMSW in order to propose the most suitable technology for an experimental pilot plant with the aim of optimizing the production of biogas. Thus, from the analysis of studies conducted it resulted that the dry AD technology in on one stage is best suited to the anaerobic treatment of OFMSW. This paper also makes an overview of the pilot plant intended for the analysis of various parameters such as process temperature, pH, organic load and the production of biogas.
The anaerobic digestion of solid wastes is now a widely-used technology in Europe with more than 50 full-scale plants operating. However, anaerobic solid waste digestion is still used to only a limited extent in North America with only three facilities in Canada. Because of the expected importance of anaerobic digestion in the future for energy recovery, reliable tools are required to evaluate the different available technologies, as well as the feed stocks that are suitable for treatment. Therefore, this paper presents a framework that has been developed for evaluating anaerobic solid waste digestion. To develop the framework, a review of the performance of digestion processes was first conducted. Because the data presented were for very different operational parameters (retention time, temperature, configuration set up, mixing, etc.) as well as substrates used for digestion, a standard method of comparison was developed. Gas production per Mg input, organic loading rate and percent volatile solids removal were identified as useful standard parameters for evaluating the performance of different technologies. This framework was constructed as a spread sheet and can be used for different set ups (configuration, organic loading rate, etc.) and with different substrates. It can predict, based on the input and using mass balances, the mass of products of the digester including biogas, treated solids and water. This framework provides a useful tool for evaluating the technical capabilities of different technologies, predicting the quantity of the products, and ultimately, making decisions as to which technologies best meet local needs.
Study of the operational conditions for anaerobic digestion of urban solid wastes
Waste Management, 2006
This paper describes an experimental evaluation of anaerobic digestion technology as an option for the management of organic solid waste in developing countries. As raw material, a real and heterogeneous organic waste from urban solid wastes was used. In the first experimental phase, seed selection was achieved through an evaluation of three different anaerobic sludges coming from wastewater treatment plants. The methanization potential of these sludges was assessed in three different batch digesters of 500 mL, at two temperature levels. The results showed that by increasing the temperature to 15°C above room temperature, the methane production increases to three times. So, the best results were obtained in the digester fed with a mixed sludge, working at mesophilic conditions (38-40°C). Then, this selected seed was used at the next experimental phase, testing at different digestion times (DT) of 25, 20 and 18 days in a bigger batch digester of 20 L with a reaction volume of 13 L. The conversion rates were registered at the lowest DT (18 days), reaching 44.9 L/kg À1 of wet waste day À1. Moreover, DT also has a strong influence over COD removal, because there is a direct relationship between solids removal inside the reactor and DT.
Anaerobic digestion of municipal solid waste
Applied Biochemistry and Biotechnology, 1995
The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as "black boxes." Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds--mainly acetate, hydrogen, and formate--on which the methanogens grow and from which they form methane. "Interspecies hydrogen-transfer" and "interspecies formate-transfer" are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Our understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.
Anaerobic Digestion of Municipal Solid Waste:A Critical Analysis
International Journal of Innovative Research in Science, Engineering and Technology, 2014
The undisposed and untreated amount of municipal solid waste (MSW) generated by different sources is a concern of the world today. There are millions of tonnes of solid waste being produced every year and amount of MSW is increasing day by day. Co-digestion of waste with other substrate mechanism may be used to decompose the maximum biomass waste generated from different source. The MSW has to be safely disposed without any negative impact to the environment. On the other hand, the generation of energy from renewable sources of energy due to depleting natural non renewable sources of energy has been becoming world’s main interest. The MSW can be one of the energy sector dreamt by the world today by use of co-digestion process. Also, the energy produced by non renewable sources of energy contributes to environmental problems such as water, land and air pollution or even global climate change. Anaerobic co-digestion as a pre-treatment prior to landfill disposal or composting offers se...
Energies
The replacement of fossil fuel with renewable energy sources seems as though it will be crucial in the future. On the other hand, waste generation increases year by year. Thus, waste-to-energy technologies fit in with the actual trends, such as the circular economy. The crucial type of generated waste is municipal solid waste, which is in the research area. Regarding the organic fraction of municipal solid waste (OFMSW), anaerobic digestion (AD) allows the recovery of biogas and energy. Furthermore, if it is supported by source segregation, it should allow the recovery of material as fertilizer. The AD process performance (biogas yield and stability) comparison of source-segregated OFMSW (ss-OFMWS) and mechanically sorted OFMSW (ms-OFMSW) as feedstocks was performed in full-scale conditions. The daily biogas volume and methane content were measured to assess AD efficiency. To verify the process stability, the volatile fatty acid (VFA) content, pH value, acidity, alkalinity, and dry ...