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It is well known that sustainability is the ideal driving path of the entire world and renewable energy is the backbone of the ongoing initiatives. The current topic of argument among the sustainability research community is on the wise selection of processes that will maximize yield and minimize emissions. The purpose of this paper is to outline different parameters and processes that impact the performance of biogas production plants through an extensive literature review. These include: comparison of biogas plant efficiency based on the use of a diverse range of feedstock; comparison of environmental impacts and its reasons during biogas production based on different feedstock and the processes followed in the management of digestate; analysis of the root cause of inefficiencies in the process of biogas production; factors affecting the energy efficiency of biogas plants based on the processes followed; and the best practices and the future research directions based on the existing life cycle assessment (LCA) studies.

The authors adopted a systematic literature review of research articles pertaining to LCA to understand in depth the current research and gaps, and to suggest future research directions.

Findings include the impact of the type of feedstock used on the efficiency of the biogas plants and the level of environmental emissions. Based on the analysis of literature pertaining to LCA, diverse factors causing emissions from biogas plants are enlisted. Similarly, the root causes of inefficiencies of biogas plants were also analyzed, which will further help researchers/professionals resolve such issues. Findings also include the limitations of existing research body and factors affecting the energy efficiency of biogas plants.

This review is focused on articles published from 2006 to 2019 and is limited to the performance of biogas plants using LCA methodology.

Literature review showed that a majority of articles focused mainly on the efficiency of biogas plants. The novel and the original aspect of this review paper is that the authors, alongside efficiency, have considered other critical parameters such as environmental emission, energy usage, processes followed during anaerobic digestion and the impact of co-digestion of feed as well. The authors also provide solid scientific reasoning to the emission and inefficiencies of the biogas plants, which were rarely analyzed in the past.

During the past ten years, anaerobic process has become a popular technology for treating concentrated effluents. Research and development programmes led by both engineers and microbiologists have resulted in a better understanding of the microbiology of anaerobic reactions and reactor design for anaerobic processes. Considerable progress has been achieved in the development of high rate anaerobic reactors with several configurations for treating concentrated industrial effluents. In this review, attention is paid to highlighting the conceptual and full scale developments of anaerobic fluidized bed reactors, in respect of process performance, design concepts, start‐up of the reactor, stability of the system with respect to various operating parameters, reactor configurations, comparison with competing reactor designs for concentrated industrial effluents and kinetics and modelling of reactor systems.

A novel cost-effective bio-digester was explored to convert biological waste into useful clean energy. The bioreactor was aimed to anaerobically digest locally sourced cow dung and chicken droppings.

The design consideration is a batch horizontal 267 L digester made from cast iron with centrally positioned four-impeller shaft to enhance mixing. The system operated with a retention time of 63 days and a substrate (cow dung and poultry waste) ratio of 1:2 and water substrate ratio of 1:0.5 in the gasholder system. The purification, compression and performance evaluation of the generated biogas were also conducted.

The total volume of gas produced for each substrate compositions designed over 14 days ranges between 49.34 and 52.91 mL/day. The optimal value of 52.45 ml using cow dung and poultry waste (w/w) 20:80 was obtained. The average ambient temperatures during the study were within the mesophilic range of 20-40°C. The pH values were stable and always in the optimal range of 6.5-8.0. The reductions in moisture content, ash content, total solids and volatile solids were from 80.50-0.20 per cent, 39.60-14 per cent, 18.50-5.90 per cent and 11.60-4.90 per cent, respectively.

The developed digester is cost-effective and would help minimize solid waste disposal. The estimated methane contents of the gas from cow dung and chicken waste after scrubbing were found to be 71.95 per cent and could be harnessed in solving the energy crisis in the developing nations.

In the EU, over the past three decades, poultry production has been growing around the 5 percent per year. This increase determined a higher volume of livestock and poultry farming waste, which represents a potential renewable fuel suitable for waste to energy conversion. One way is through biological process such as the dry anaerobic digestion (AD). Tests normally applied for the measurement of the anaerobic biogas potential (ABP) are reliable, but not feasible as a routine analysis. This kind of test is expensive and time consuming (21-100 days). The purpose of this paper is to propose a rapid method for assessing the potential of biogas in anaerobic poultry manure, with the goal of helping the choices of operators of AD.

The Dynamic Respiration Index was calculated as “key parameter” in order to estimate the ABP, which provides important information about the biogas generation for the poultry manure. Furthermore, two dynamic respirometric approaches were considered developed in two Italian universities. The main difference between them is the control of temperature.

Calculate ABP through IRD is a useful method to determine the value of the potential production of biogas of different biomasses in a short time and assess which one is more productive.

The methodology presented in this study is fast (one-five days) and alternative method to determinate the ABP, above all for the operators of AD plant.

This study aims to offer a research overview of circular food waste management, covering key themes and trends. It analyses state-of-the-art research in this field and proposes an agenda to guide future research.

This study outlines bibliometric analysis from a sample of 349 articles with VOSviewer and SciMat software to identify research trend topics.

The findings reveal a substantial amount of interest in this field. The main research topics relate to the recovery processes and valorisation of food waste and its conversion into renewable and cleaner materials or energy sources, towards circularity. However, these processes require consideration of social aspects that facilitate their implementation, which are currently under-researched.

Companies can target their circular food waste management by considering three key aspects. Firstly, the establishment of closer and more sustainable relationships with various stakeholders; Secondly, a regulatory framework and the support of institutions are both required for the correct implementation of circularity. Finally, what is not measured does not exist. It is therefore necessary to establish indicators to measure both the level of development of circularity in waste management and the fulfilment of the established objective.

This bibliometric analysis looks at the application of circularity principles in food waste management from a holistic perspective, considering different areas of knowledge.

Food‐processing operations produce many varied types of wastes which include solid and liquid effluents and, to a much lesser extent, volatile organic compounds, e.g. refrigerants. Economic, legislative and social pressures are forcing food industries to reconsider their attitude towards the generated effluents. Waste processing is no longer regarded as a series of operations intended to render wastes suitable for discharge into the atmosphere or a water body. It is an integral part of the mainstream activity of any industry. Discusses the characteristics of food‐processing wastes and their environmental impact and highlights strategies for efficient waste management.

This paper seeks to focus on a combined waste (or: wastewater)/energy system in the deep green housing district named “EVA Lanxmeer” in Culemborg (The Netherlands). An innovative mixture of “red and green” development is presented, together with a concept of building integrated decentralized technologies for wastewater and organic waste treatment with energy and nutrients recovery. The concept is called sustainable implant.

The methodology of the research is based on Van Strien's “regulative cycle” in which theoretic parts, on the one hand, and practice‐related parts, on the other hand, are distinguished. The theoretical part concerns a flow analysis of existing and new sustainable technologies for preserving the (energy, water and waste) flows, an analysis of the different options for transportation, the accompanying technical infrastructure, and an analysis of possible levels or scales of implementation. The practice‐related part of the research consists of case studies and the final design of the sustainable implant for the district EVA Lanxmeer.

It is important to change the general attitude towards the different components of design, development, use and management of urban areas. A way to do so is the “interconnection” of different themes and cycles within cities. An example is the linking of sanitation to energy and food production. The paper shows the potentials of integrating solutions concerning energy and sanitation flows as near as possible to its origin of use and/or production. Introducing the analogy of the functioning of buildings (with respect to energy and sanitation flows) with that of a parasite.

The system layout and the dimensioning backgrounds are explained in this paper. Additional emphasis is put on maintenance, conservation and administration of the integrated whole, and the possible consequences for the district and its inhabitants. There are scale limitations concerning the proposed (and realized) systems. Besides that there is a matter of a unique situation with an “intentional community”.

Although two similar systems, however small, have been realized, no other project (in process of realization) can be found worldwide in which there is a linking of urban agriculture, waste(water) treatment and energy production at the scale of an urban district.

Human activities in household and industries generate an enormous amount of waste material, both organic and non-biodegradable matter, which substantially contribute to land, water and air contamination. The study aims to highlight the possible methods in solid waste management (SWM) and its influence on economy and environment. The paper is an attempt to bring out the necessity of corporate social responsibility (CSR) in the management of solid waste.

The paper is prepared after an elaborate review of literature connected with SWM.

The paper emphasizes the need of SWM and the role of corporate bodies in building a robust system in the management of solid waste, creating a healthy environment to all.

The paper is entirely based on literature review and reports and not on individual's research.

The paper has a multi-level faceted approach where real-time practices in different countries have been explored.

This study can enable the collaboration of corporates, scientific community and the municipal local bodies in the area of SWM.

This paper deliberates on how CSR can be a driving force for a sustainable model for SWM.

Bioenergy as a renewable energy type is found as a promising method to replace non-renewable energy. Anaerobic co-digestion, in which the microorganisms of two or more substrates break into biodegradable materials without oxygen, and fermentation, in which substances break into a simpler form in the presence of microorganisms and some bacteria, are the two frequently used methods that are were applied in this work.

A farmland currently being used for farming was selected, and the bioenergy potential of the farmland was evaluated by using the aforementioned two methods. In this work, segregated municipal wastes which were collected from nearby areas and animal manure were used as feedstock for anaerobic co-digestion, whereas wheat straw obtained from the farmland was used as feedstock for fermentation.

The total input energy required for the digestion systems and the collection of the feedstock products from the growth to the harvest phases was calculated. Thereafter, the generated output energy was calculated to obtain an energy balance of the techniques. All the processes were taken into account during the prediction of the cost of the given power plant. The power output capacity of the farmland was 245 MW with a total cost of $540,200.

Because of the chosen research approach, the research results may lack generalisability. Therefore, researchers are encouraged to test the proposed propositions further.

The result proves that the two methods were applicable and feasible to replace for the 200 ha farmland.

Anaerobic digestion can be used to treat many organic waste streams. However, fish wastes pose a particular technological problem, as they release high levels of ammonia when digested, which then inhibits the digestion process. Having overcome these technical problems, it is important that there is a long term, financially viable outlet for the products of the digestion process. The organic sector places high demands on the production of certified inputs, but, if these can be met, this sector represents a potentially high value market for the products of a digestion process.