Waste-to-energy: A review of life cycle assessment and its extension methods

A simulation and risk assessment framework for water-energy-environment nexus: A case study in the city cluster along the middle reach of the Yangtze River, China

In the Anthropocene, there is a strong interlinkage among water, energy, and the environment. The water-energy-environment nexus (WEEN) has been vigorously advocated as an emerging development paradigm and a global research agenda. Based on the nexus concept, a framework for the WEEN complex system simulation and risk assessment is developed. The three metropolitan areas of the city cluster along the middle reaches of the Yangtze River (CCMRYR) are taken as the objects. Regional policies are combined with generic shared socio-economic pathways (SSPs) to form a localized SSPs suitable for the research region. The dynamic simulation of the WEEN complex system and the risk analysis are carried out with the combination of system dynamics models and copula functions. Results show that: There are obvious differences in water utilization, energy consumption, air pollutant emissions, and water pollutant emissions among the three metropolitan areas. The issue of high carbon intensity in the Wuhan Metropolitan Coordinating Region needs to be emphasized and solved from the perspective of optimizing the industrial structure. Adhering to current development patterns, there will be successive peaks in water utilization, energy consumption, and carbon emissions in Wuhan, Dongting Lake, and Poyang Lake Metropolitan Coordinating Region by 2030, leading to high synergy risks at the systemic level, with maximum values of 0.84, 0.85, 0.62, respectively. A development path based on conservation priorities indicates that future policymaking needs to prioritize a resource-saving and pollution-control development pattern directed by technological upgrading against the backdrop of scarce natural resource endowments. The localized SSPs are a beneficial extension that enriches the narrative of regional-scale SSPs. The evolutionary trajectories and risk assessments of WEEN complex systems under different localized SSPs provide a sweeping insight into the consequences of policy decisions, thus enabling policymakers to appraise policy rationality and implement appropriate corrective measures.

Application of q-rung orthopair fuzzy based SWARA-COPRAS model for municipal waste treatment technology selection

Despite several methods available for the treatment of solid wastes, the management of municipal solid waste is still a crucial and complex process. The available methods for waste treatment range from advanced to conventional techniques. The identification of a proper method for municipal solid waste management involves several techno-eco and environmental considerations. To solve the real-world problems of municipal waste management, the research proposed an integrated q-rung orthopair fuzzy number-based stepwise weight assessment ratio analysis-complex proportional assessment (SWARA-COPRAS) mathematical model to rank the waste treatment techniques. The research aimed to develop a systematic approach for a suitable selection of waste treatment methods. Ten (10) different alternatives for waste treatments were ranked against seven (07) different techno-eco and environmental criteria. The ambiguity in the decision was handled by the q-rung orthopair fuzzy numbers. The proposed integrated model has identified upcycling and recycling of waste having priority values of 100% and 99.9%, respectively, as the suitable practices for the successful management of generated solid wastes, whereas landfilling has obtained a minimum priority value of 66.782% and, therefore, is least preferable for waste management. The ranking of the alternatives followed the sequence as upcycling > recycling > pyrolysis > hydrolysis > biotechnological > core plasma pyrolysis > incineration > composting > gasification > landfilling. The comparison between the rankings of the proposed model with other techniques has revealed that the values of Spearman's rank correlation coefficient are in the range of 0.8545 to 0.9272; thereby, the robustness of the proposed model is verified. Sensitivity analysis for the criteria weight has showed that the ranking results are influenced significantly by the change in criteria weights and suggested that an accurate estimation of the criteria weight is decisive in determining the overall ranking of the alternative. The study has provided a framework for decision-making in the technology selection for solid waste management.

Applicability of the Life Cycle Assessment Model in Solid Waste Management in Zimbabwe

Solid waste increase is inevitable globally due to anthropogenic activities. This adds burden to waste management systems in developing countries including Zimbabwe. Currently, life cycle assessment (LCA) model is used to achieve sustainability and circular economy (CE) in solid waste management. Therefore, the main goal of this paper was to unearth LCA model applicability in solid waste management in Zimbabwe. Data sources were retrieved from databases like Scopus, ScienceDirect and Springer, although government documents were also used. In Zimbabwe, organic and inorganic solid waste is generated from various sources, namely industries, institutions and households. Solid waste management in Zimbabwe is based on traditional linear approach where waste is collected and disposed through landfilling, burning, incineration, burying, open pits or illegally. Most disposal approaches occupy base of waste management pyramid, hence posing detrimental impacts to human health, terrestrial, aquatic and atmospheric ecosystems. Management approaches are far from Agenda 21, Sustainable Development Goals (SDGs), Zimbabwe Vision 2030 and National Development Strategy 1 demands. Literature revealed that LCA model can be utilised to achieve sustainable solid waste management in countries like Zimbabwe. LCA model is essential in management of solid waste in Zimbabwe, since it assists decision makers in selecting management approaches with less environmental health impacts. Moreover, LCA enables application of waste material reuse, recycle, repairing and recovery, thus narrowing the gap to achieve CE and economic growth in Zimbabwe. Owing to LCA model implementation of waste management legislation and policies which support energy recovery and circular economy became easier in Zimbabwe.

Waste to energy incineration technology: Recent development under climate change scenarios

With the huge generation of municipal solid waste (MSW), proper management and disposal of MSW is a worldwide challenge for sustainable development of cities and high quality of citizens life. Although different disposal ways are available, incineration is a leading harmless approach to effectively recover energy among the applied technologies. The purpose of the present review paper is to detail the discussion of evolution of waste to energy incineration and specifically to highlight the currently used and advanced incineration technologies, including combined incineration with other energy, for instance, hydrogen production, coal and solar energy. In addition, the environmental performance is discussed, including the zero waste emission, leachate and fly ash treatment, climate change contribution and public behaviour. Finally, challenges, opportunities and business model are addressed. Trends and perspectives on policies and techno-economic aspects are also discussed in this review. Different simulation tools, which can be used for the thermodynamic assessment of incineration plants, are debated; life-cycle inventory emissions and most critical environmental impacts of such plants are evaluated by life-cycle analysis. This review shows that waste incineration with energy yield is advantageous to handle waste problems and it affects climate change positively.

Life cycle assessment of microalgal biorefinery: A state-of-the-art review

Microalgal biorefineries represent an opportunity to economically and environmentally justify the production of bioproducts. The generation of bioproducts within a biorefinery system must quantitatively demonstrate its viability in displacing traditional fossil-based refineries. To this end, several works have conducted life cycle analyses on microalgal biorefineries and have shown technological bottlenecks due to energy-intensive processes. This state-of-the-art review covers different studies that examined microalgal biorefineries through life cycle assessments and has identified strategic technologies for the sustainable production of microalgal biofuels through biorefineries. Different metrics were introduced to supplement life cycle assessment studies for the sustainable production of microalgal biofuel. Challenges in the comparison of various life cycle assessment studies were identified, and the future design choices for microalgal biorefineries were established.

Greenhouse Gas Emissions from Beef Cattle Breeding Based on the Ecological Cycle Model

Over the past few decades, the supply of beef has increasingly become available with the great improvement of the quality of life, especially in developing countries. However, along with the demand for meat products of high quality and the transformation of dietary structure, the impact of massive agricultural greenhouse gas emissions on the environmental load cannot be ignored. Therefore, the objective of this study is to predict the annual greenhouse gas emissions of 10 million heads of beef cattle under both the ecological cycle model (EC model) and the non-ecological cycle model (non-EC model), respectively, in order to compare the differences between these two production models in each process, and thus explore which one is more sustainable and environmentally friendly. To this end, through the life cycle assessment (LCA), this paper performs relevant calculations according to the methodology of 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories (2019 IPCC Inventories). The results have shown that the total GHG emissions of the non-EC model were almost 4 times higher than those of the EC model, and feed-grain cultivation and manure management were main emission sources in both models. The non-EC model produced significantly more emissions than the EC model in each kind of GHG, especially the largest gap between these two was in CO₂ emissions that accounted for 68.01% and 56.17% of the respective planting and breeding systems. This study demonstrates that the transformation of a beef cattle breeding model has a significant direct impact on cutting agricultural GHG emissions, and persuades other countries in the similar situation to vigorously advocate ecological cycling breeding model instead of the traditional ones so that promotes coordinated development between planting industry and beef cattle breeding industry.

A systematic review of life cycle assessment of solid waste management: Methodological trends and prospects

Solid waste disposal has led to increasing concerns over resource, health, and environmental problems. These issues have been investigated using the Life Cycle Assessment (LCA) technique which helps identify the roots of varying hazards and allows decision-makers to improve the environmental performance of waste management practices. However, there is a lack of review studies that conducted meta-analysis related to developments in critical methodological steps of LCA on solid waste management. To fill this gap, this review paper examines 15 elements comprising the preference of journals, 13 LCA method-related characteristics, and economic assessment. Insights on the limitations and current practices of LCA applications, along with trends for future research, are provided. 240 studies on the LCA of SWM from 2009 until 2020 were systematically reviewed and classified into two major year-groups (i.e., 2009-2014 and 2015-2020) to investigate the trend changes. Among the studied elements, it is found that energy-related applications are on the increase in LCA studies on solid waste management. Anaerobic digestion facilities nearly double in appearance in the second year-group (2015-2020). There is also a more frequent occurrence of certain characterization methods like ReCiPe and CML. Functional units become more diverse, but are overall mostly defined on a mass basis. A frequently identified issue of many LCAs on solid waste management is the ambiguity of data sources such as out-of-date literature or inconsistent geographical references. By addressing issues of methodological standardization, this review study provides a basis to further increase the reliability of results of future LCA studies on solid waste management.

Cost-Effectiveness of Life Cycle Cost Theory-Based Large Medical Equipment

The purpose of this study is to use the life cycle cost theory to analyze the efficiency of large medical equipment in hospitals, so as to implement life cycle cost (LCC) management and solve the current problems in hospitals. The analysis model of cost benefit of large medical equipment is established, and the cost-effectiveness of 4 large medical equipment between 2019 and 2021 is investigated and analyzed. In terms of the data in each information system of hospitals, the utilization of large medical equipment is quantitatively evaluated and analyzed by life cycle theory. The results show that the Revolution 256 row has the highest revenue of 113.29%. The annual depreciation of Signa 3.0 T HDxt is the highest, amounting to 4,160,000 yuan. However, there is lack of quality control and preventive maintenance of most equipment during use. The cost and benefit of large medical equipment in hospitals are analyzed, which demonstrates that Signa 3.0 T HDxt shows better effectiveness. Too high hospital warranty cost reflects the weak maintenance strength of hospital engineering technicians. The fundamental point of the maintenance and management of large medical equipment is to strengthen the performance evaluation of medical engineering technicians.

Environmental and energy performances of the Italian municipal solid waste incineration system in a life cycle perspective

The environmental and energy performances of the Italian municipal solid waste incineration (MSWI) system was investigated by a life cycle assessment approach. On average the 39 MSWIs operating in Italy in 2018 treated about 6,000,000 Mg of residual municipal solid waste (RMSW) recovering on average from 448 kWh Mg^-1 RMSW to 762 kWh Mg^-1 RMSW of electricity and from 732 kWh Mg^-1 RMSW to 1102 kWh Mg^-1 RMSW of heat. The average quantity of CO₂eq Mg^-1 RMSW emitted ranged from about 800 up to about 1000 depending on the size and on the energy recovery scheme of the facility. Avoided impacts (i.e., negative values) were detected for the kg PM_2,5eq Mg^-1 RMSW and for human health (disability-adjusted life year Mg^-1 RMSW). The determination of the hybrid primary energy index (MJ Mg^-1 RMSW) indicated that mainly large size facilities and those operating according to a power and heat energy recovery scheme are effectively able to replace other primary energies by the exploitation of the lower heating values of the RMSW.

Application of Green Design and Manufacturing in Mechanical Engineering: Education, Scientific Research, and Practice

Green design and manufacturing strategies are necessary to cope with the current resource, energy, and environmental problems of the manufacturing industry. To meet various enterprises’ needs for green design and manufacturing, colleges and universities should integrate these concepts into their curricula. This study discusses the application of green strategies in the mechanical engineering field from the viewpoints of teaching, scientific research, and practical education. Based on its development and a basic connotation analysis, this study highlights the challenges and urgency of incorporating green concepts into teaching and research modules of mechanical engineering, as well as methods and implementation strategies to incorporate them in professional curricula using teaching method reform and the teaching and research integration method. An experimental training course of advanced manufacturing processes at the authors’ institution was amended to emphasize the integrated application of green design and manufacturing. This integration not only enriches the field of mechanical engineering but also provides scientific research directions and methods to educators, along with new ideas to imbibe students with mechanical talents for their technical development. These efforts lay the foundation for the sustainable development of China’s manufacturing industry.

Effect of calcium-based sorbents on the reduction of chlorinated contaminants during municipal solid waste thermal treatment

Chlorinated contaminants are a cause of significant concern in the development of municipal solid waste (MSW) thermal treatment techniques. This study investigates the efficacy of two calcium (Ca)-based in-furnace additives, calcium oxide (CaO), and calcined dolomite (CD), at reducing the levels of chlorinated contaminants during MSW thermal treatment. The results reveal that Ca-based additives could effectively reduce the chlorine (Cl) content by more than 76.8% and 37.3% in the gas and tar phases, respectively. The total concentration and the international total equivalent (I-TEQ) value of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) were significantly higher under the incineration condition than pyrolysis and gasification conditions. Adding CaO could reduce the total concentration and the I-TEQ value of PCDD/Fs by more than 43.4% and 36.7%, respectively. The reduction effect on PCDD/Fs was more significant in the gaseous phase and the tar phase than the solid phase. CD was more effective than CaO at reducing the chlorinated contaminants, including hydrogen chloride, Cl in the tar phase, and PCDD/Fs. Thus, adding Ca-based sorbents in the furnace during MSW pyrolysis and gasification can effectively reduce PCDD/Fs generation. Based on the experimental results, the mechanism of Ca-based sorbents on the high-temperature homogeneous reaction of PCDD/Fs formation was analysed.

Life cycle assessment of environmental impact on municipal solid waste incineration power generation

Municipal solid waste (MSW) incineration power generation is an important treatment technology, which has been widely concerned in recent years. It is of great significance to evaluate the environmental impact. This study conducted the environmental life cycle assessment of MSW incineration power plant in Yongcheng city, Henan province, China. After that, the comprehensive environmental impacts of MSW incineration power plant, landfill, and coal-fired power plant are compared. Furthermore, the energy conservation and emission reduction benefits brought by MSW incineration power plant in Yongcheng city are quantitatively analyzed. The results show that (1) the main environmental impact categories of MSW incineration power plant are human toxicity potential and acidification potential, which together account for 72.8% of the total comprehensive environmental impact. In addition, incineration is the main process of pollutant generation, which contributes 94.1% to the comprehensive environmental impact. (2) As an effective supplement to landfill and coal-fired power generation, MSW incineration power generation produces lower environmental impact. (3) Significant energy-saving and emission reduction benefits can be brought by MSW incineration power plant. Particularly, it could save energy 2.75×10⁴ tce, reduce greenhouse gas emissions 3.43×10⁵ t CO₂-eq, and effectively reduce the emissions of various air pollutants for the local area annually.

Catalytic pyrolysis of mechanically non-recyclable waste plastics mixture: Kinetics and pyrolysis in laboratory-scale reactor

Post-consumer waste plastics that cannot be mechanically recycled represent a concerning environmental issue. According to the latest available data for Europe, as much as 25% of collected post-consumer waste plastics are landfilled, 43% is energy recovered, and 32% is recycled. One possible way of recovering non-recyclable plastics is pyrolysis, which is considered environmentally friendly technology for obtaining fuel or chemicals from plastic waste. To tackle the challenge of recovering non-recyclable plastics via pyrolysis, it is necessary to determine their actual composition. Visual separation of collected non-recyclable plastics was performed, and Fourier-transform infrared spectroscopy was used to confirm the accuracy of visual separation. A significant amount of plastics labelled as "other" was found. Since the composition of "other" waste plastics has not been sufficiently investigated, relatively few studies on their pyrolysis have been conducted. Therefore, they were characterised and added to the mixture with other found polymer types of non-recyclable plastics. Thermogravimetric analysis was conducted to determine thermochemical behaviour and kinetic parameters required for laboratory pyrolysis investigation. Kinetic analysis was conducted using the Friedman isoconversional model-free method and non-linear multivariate regression method. The goal of this paper was to analyse the kinetics, determine the product yield and characteristics of the pyrolysis process of non-recyclable plastics over zeolite catalysts. It was found how the decomposition of non-recyclable plastics occurs in two decomposition steps. The activation energy of non-recyclable plastics was 144 kJ/mol in the first stage of decomposition and 262 kJ/mol in the second stage of decomposition. It decreased by 34% and 6.5% after fresh fluid catalytic cracking catalyst was added and 41% and 18.3% with iron-modified Zeolite Socony Mobil-5 catalyst. The yield of condensate was 55% (wax) for the original sample, and it decreased to 50% (wax and oil) and 27% (mostly oil) with fresh fluid catalytic cracking and iron modified Zeolite Socony Mobil-5 catalysts. Processes with catalysts promoted the formation of olefins and aromatic compounds in pyrolytic oil. All pyrolysis products had a high value of higher heating value ranging from 39 MJ/kg to 43 MJ/kg showing good potential for further energy use.

Odour Nuisance at Municipal Waste Biogas Plants and the Effect of Feedstock Modification on the Circular Economy—A Review

The increase in the amount of municipal solid waste (MSW) generated, among other places, in households is a result of the growing population, economic development, as well as the urbanisation of areas with accompanying insufficiently effective measures to minimise waste generation. There are many methods for treating municipal waste, with the common goal of minimising environmental degradation and maximising resource recovery. Biodegradable waste, including selectively collected biowaste (BW), also plays an essential role in the concept of the circular economy (CE), which maximises the proportion of waste that can be returned to the system through organic recycling and energy recovery. Methane fermentation is a waste treatment process that is an excellent fit for the CE, both technically, economically, and environmentally. This study aims to analyse and evaluate the problem of odour nuisance in municipal waste biogas plants (MWBPs) and the impact of the feedstock (organic fraction of MSW-OFMSW and BW) on this nuisance in the context of CE assumptions. A literature review on the subject was carried out, including the results of our own studies, showing the odour nuisance and emissions from MWBPs processing both mixed MSW and selectively collected BW. The odour nuisance of MWBPs varies greatly. Odour problems should be considered regarding particular stages of the technological line. They are especially seen at the stages of waste storage, fermentation preparation, and digestate dewatering. At examined Polish MWBPs cod ranged from 4 to 78 ou/m3 for fermentation preparation and from 8 to 448 ou/m3 for digestate dewatering. The conclusions drawn from the literature review indicate both the difficulties and benefits that can be expected with the change in the operation of MWBPs because of the implementation of CE principles.

The life cycle approach for assessing the impact of municipal solid waste incineration on the environment and on human health

The impact of municipal solid waste incineration (MSWI) on the environment and on human health was assessed by a life cycle assessment (LCA) approach. Even if risk assessment and epidemiologic analyses are specifically indicated for the investigation of the health outcomes, they resulted costly, time intensive and generally focused only on the effects caused by pollutant compounds directly emitted by the facility. Differently, LCA approaches are less time and cost intensive and able to account also for other indirect and direct emission of MSWI. However, results returned by LCA are based on average pollutant diffusion and individual exposure models limiting their representativeness for the specific context investigated. Furthermore, LCA is not able to return information about the final health outcomes caused by the pollutants emitted. The LCA performed for the Italian MSWI detected avoided impacts of about -0.11 kgPM_2,5eq/tonne of MSW and of about -2.5 × 10^-3 kgSb_eq/tonne MSW for particulate matters and resource depletion, respectively. Positive impacts of about 900 kgCO_2eq/tonne MSW and about 15,000 CTUe/tonne MSW were detected for global warming and freshwater ecotoxicity indicators, respectively. Avoided impacts of about -1 × 10^-6 CTUh/tonne MSW and of about -2 × 10^-4 DALY/tonne MSW were also detected for human toxicity cancer and human health indicators, respectively. Epidemiologic studies referred to different Italian and EU reported some correlations among MSWI and some specific cancer and non-cancer health outcomes. By the way, these resulted affected by some methodological limitation preventing the definitive identification of causal nexus. In any case, a general coherence between LCA and epidemiologic approaches was detected. Furthermore, a particular correspondence was found between LCA results and biomonitoring studies concerning the concentration of heavy metals in blood and urinary samples of exposed individuals. All this highlighted the important role that LCA can have in supporting health impact assessment of MSWI in combination with epidemiologic approaches.

Research Regarding the Energy Recovery from Municipal Solid Waste in Maramures County Using Incineration

This paper presents a part of the study referring to exploring Energy Recovery from Municipal Solid Waste in Maramures County. In order to analyze the possibility of energetic recovery of municipal solid waste (MSW), data referring to the management system of MSW from Maramures county were cumulated and processed in a first stage in order to estimate the quantity of municipal solid waste and its composition, which might be recovered energetically. In the next stage, samples of municipal solid waste were collected from landfills, which were submitted to specific processing and analyses. The experimental data were processed and in the end the energy potential of municipal solid waste from Maramures county was found. This study will help stakeholders and those involved in waste management to assess the possibility of energy recovery. The analysis of the study concluded that municipal solid waste in Maramures County is a potential source of renewable energy.

Environmental profile of thermoelectrics for applications with continuous waste heat generation via life cycle assessment

Over the past few decades, rigorous efforts have been undertaken to develop novel thermoelectrics (TEs) with high conversion efficiencies. However, poor TE device efficiencies and use of scarce and toxic constituent elements in major TEs raises valid questions about their ecological effectiveness. We evaluate this efficacy by investigating environmental performance of seven TE modules, spanning five different TEs, on a diverse range of impacts (including toxicity and scarcity) over their life cycle (cradle-to-grave). Exhaustive inventory is developed for all modules, particularly their production and end-of-life stages, in the first-ever exercise of its kind till date, to assess their benefits for applications involving constant waste heat emission. Three end-of-life scenarios are considered to determine ecological benefits and pitfalls of recycling TEs, a first in LCA literature on thermoelectrics. The results show the dominance of specific constituent elements and large processing-related electricity consumption on impacts caused by production for all modules. Over their life cycle, TE modules are seen to exhibit large positive environmental benefits, barring some exceptions, highlighting their substantial eco-credentials independent of the TE used. Also, barring circular economy approach in some cases, no end-of-life treatment is observed to significantly influence modular environmental impacts. Subsequent calculations show ecological benefits from TEs to be comparable with those from commonly used renewables like solar and wind energy, with the findings repeated under scenario-based sensitivity analysis despite 50% reduction in conversion efficiency and 15% lowering in usage duration, further validating their ecofriendly potential. Simultaneously, two key challenges that hinder large-scale application of TEs - marginal ecological benefits (even on converting high fraction of waste heat to electricity) and high costs - are pointed out. This work concludes by highlighting the urgent need for addressing major negative contributors to production-related impacts of this platform to boost its prospects for commercial application and transform its ecofriendly potential into reality.

Biowaste Treatment and Waste-To-Energy—Environmental Benefits

Biowaste represents a significant fraction of municipal solid waste (MSW). Its separate collection is considered as a useful measure to enhance waste management systems in both the developed and developing world. This paper aims to compare the environmental performance of three market-ready technologies currently used to treat biowaste—biowaste composting, fermentation, and biowaste incineration in waste-to-energy (WtE) plants as a component of residual municipal solid waste (RES). Global warming potential (GWP) was applied as an indicator and burdens related to the operation of facilities and credits obtained through the products were identified. The environmental performance of a WtE plant was investigated in detail using a model, implementing an approach similar to marginal-cost and revenues, which is a concept widely applied in economics. The results show that all of the treatment options offer an environmentally friendly treatment (their net GWP is negative). The environmental performance of a WtE plant is profoundly affected by its mode of its operation, i.e., type of energy exported. The concept producing environmental credits at the highest rate is co-incineration of biowaste in a strictly heat-oriented WtE plant. Anaerobic digestion plants treating biowaste by fermentation produce fewer credits, but approximately twice as more credits as WtE plants with power delivery only.

Efficient biodegradation of organic matter using a thermophilic bacterium and development of a cost-effective culture medium for industrial use

Microorganisms with efficient organic matter degradation ability are essential for organic waste treatment. In this study, a thermophilic bacterium, Bacillus thermoliquefaciens, was identified to have excellent cellulase, amylase, and protease activity, and provided efficient degradation of food waste. This is the first report on the organic matter degradation potential of B. thermoliquefaciens. Using a "one-variable-at-a-time" approach and response surface methodology, the optimal culture conditions for B. thermoliquefaciens were determined to be a 5% inoculation level, 50 °C culture temperature, 25 mL filling volumes in 250 mL flasks, and 180 rpm shaking for 24 h. The optimized medium was formulated as 1 g Na₂HPO₄, 1 g KH₂PO₄, 0.05 g MgSO₄, 3 g NaCl, 0.05 g CaCl₂, 11.44 g wheat bran powder, 4.92 g soybean meal, and 1 L distilled water at pH 7.12. The maximum biomass attained was 1.57 ± 0.153 × 10⁹ CFU/mL. The cost of this medium was 4.18 times less than that before optimization. This promising result lays a foundation for future industrial application of this bacterium to the degradation of organic waste.

Empirical Research on the Process of Land Resource-Asset-Capitalization—A Case Study of Yanba, Jiangjin District, Chongqing

As an effective land policy that can invigorate rural construction areas and balance urban and rural development, land tickets not only concretely embody the land resource-asset-capitalization process, but also bring economic benefits to the farmers concerned. However, from the perspective of resource-asset-capitalization, the specific environmental impacts and economic costs of the process in land tickets and the changes in the values of ecosystem services need to be considered. This paper uses land tickets in Yanba, Jiangjin, Chongqing as an example, combined with life cycle assessment (LCA), life cycle cost assessment (LCC), and methods for the evaluation of ecosystem services to quantify the environmental load, economic costs, and changes in the value of ecosystem services in the process of land resource-asset-capitalization. Moreover, through this analysis, we attempted to determine the contributions of different environmental indicators and the key links restricting the whole process of land resource-asset-capitalization. On this basis, through a sensitivity analysis, we explored the possibility of reducing environmental impact during the whole process of land resource-asset-capitalization. Through this research, we sought to explore the realization process of land tickets and to enrich the empirical research on land resource-asset-capitalization.

Optimization of recyclable MSW recycling network: A Chinese case of Shanghai

The establishment of recycling network is critical to improve municipal solid waste (MSW) management. However, how to determine the best locations for the recycling stations and recycling centers remains to be solved. Under such a circumstance, this study aims to forecast the MSW generation and develop a cost-based location optimization model using p-median method so that the optimal scale and location of recycling centers can be identified. Shanghai, with an ambitious plan for promoting MSW recycling at the city level, was selected as a case study city. Results show that Shanghai's MSW generation rate will be about 3% from 2017 to 2020. Regional distribution analysis shows that the downtown areas have higher intensity for MSW generation due to high population density and consumption level. Fourteen regional recycling centers were identified to be the optimal places for establishing recycling centers. The achievement of this scenario can lead to the lowest total cost of 144 million Chinese Yuan. Moreover, the optimal results may change if unit transportation cost and unit scale cost are changed. For instance, the optimal numbers of recycling centers will increase with the increase of unit transportation cost or decrease of unit scale cost. Finally, model limitations and policy recommendations are raised by considering the local realities.

Feasibility Assessment of a Bioethanol Plant in the Northern Netherlands

Due to the exhaustion and increased pressure regarding the environmental and political aspects of fossil fuels, the industrial focus has switched towards renewable energy resources. Lignocellulosic biowaste can come from several sources, such as industrial waste, agricultural waste, forestry waste, and bioenergy crops and processed into bioethanol via a biochemical pathway. Although much research has been done on the ethanol production from lignocellulosic biomass, the economic viability of a bioethanol plant in the Northern Netherlands is yet unknown, and therefore, examined. In this thesis, the feasibility study of a bioethanol plant treating sugar beet pulp, cow manure, and grass straw is conducted using the simulation software SuperPro Designer. Results show that it is not economically viable to treat the tested lignocellulosic biomass for the production of bioethanol, since all three original cases result in a negative net present value (NPV). An alternative would be to exclude the pretreatment step from the process. Although this results in a lower production of bioethanol per year, the plant treating sugar beet pulp (SBP) and grass straw (GS) becomes economically viable since the costs have significantly decreased.

A PESTLE Analysis of Biofuels Energy Industry in Europe

Biofuels production is expected to be an intrinsic confluence to the renewable energy sector in the coming years under the European regulations for renewable energy. Key standpoints of the biofuels promotions are the reduction of national carbon emissions and rural deployment. Despite jubilant outlook of biofuels for sustainable development, research efforts still tend to link the biofuel industry and regional growth. The aim of this study is to explore and review the biofuels industry through a socio-political, techno-economic, legal and environmental (PESTLE) analysis approach, and discuss the interrelation between technological facets and sustainable deployment.

Critical review on life cycle assessment of conventional and innovative waste-to-energy technologies

In this study 315 peer-reviewed studies on environmental life cycle assessment (LCA) of waste-to-energy (WtE) technologies were critically analysed. The technologies considered were anaerobic digestion, hydrothermal carbonization, pyrolysis, gasification and incineration. It was found that overall increasingly more studies are concerned with LCA on waste-treatment systems. Although incineration and anaerobic digestion were primarily assessed, especially in recent years, a growing number of LCA-studies investigated advanced thermal treatment options. The geographical scope within the studies under review focused mainly on European (195 studies) and Asian (68 studies) regions. In regards to their quality, a majority of the analysed studies were marked by several shortcomings and showed poor compliance with the ISO 14040 and ISO 14044. 55 studies did not present a functional unit and >45% of all reviewed studies did not present a life cycle inventory. More than 50% of the reviewed studies omitted a sensitivity analysis and a comprehensive assessment of all impact categories was not present in most studies. By selecting studies that analysed two or more different WtE treatment options, the global warming potential and the acidification potential of the considered five different technologies were compared. By contrasting advanced treatment options against incineration, substantial environmental benefits of advanced treatment options could not be observed. However, only 34 studies fulfilled the criteria to be taken into account for this comparison. The main finding within this scope, was that anaerobic digestion and gasification seemed to outcompete incineration in the conversion process of waste. Cascaded waste treatment, i.e. combining several treatment technologies, was only present in few studies. Environmental benefits could be assigned to these treatment paths in most cases. Lastly, techno-economic aspects are highlighted and appropriate policies are deducted from the obtained results.

Environmental performance evolution of municipal solid waste management by life cycle assessment in Hangzhou, China

There is a significant increase in the volume of Municipal Solid Waste (MSW) that is being generated across the world. Faced with this challenge and the associated environmental issues, MSW management (MSWM) in Hangzhou, China has made various positive changes in order to adapt. During the last 10 years, MSW source-separated collection was launched, which was accompanied by estimations of a new waste-to-energy (incineration) plant and food waste separate treatment methods. The aim of this study is to investigate the related evolution of the environmental performance of MSWM system in Hangzhou from 2007 to 2016 by using life cycle assessment (LCA). LCA is a scientific tool to quantify factors such as environmental impacts from a life cycle perspective and provides valuable inputs to decision-makers, thus leading to proper strategy determination. Results illustrate that the annual environmental performance has an overall downward trend with some minor fluctuations. The MSWM system in 2010 had the lowest weighted result of 0.0349 PE/t-MSW due to the highest incineration rate and implementation of source-separated collection. Incineration shows better environmental performance than landfill, while source-separated collection can benefit the MSWM. While the importance of source-separated collection is significant, it is also essential to concentrate on the food waste treatment technology. It is suggested that anaerobic digestion (AD) can be considered as a primary option for food waste treatment.

Anaerobic digestion of municipal solid waste: Energy and carbon emission footprint

Anaerobic digestion (AD) serves as a promising alternative for waste treatment and a potential solution to improve the energy supply security. The feasibility of AD has been proven in some of the technologically and agriculturally advanced countries. However, development is still needed for worldwide implementation, especially for AD process dealing with municipal solid waste (MSW). This paper reviews various approaches and stages in the AD of MSW, which used to optimise the biogas production and quality. The assessed stages include pre-treatment, digestion process, post-treatment as well as the waste collection and transportation. The latest approaches and integrated system to improve the AD process are also presented. The stages were assessed in a relatively quantitative manner. The range of energy requirement, carbon emission footprint and the percentage of enhancement are summarised. Thermal hydrolysis pre-treatment is identified to be less suitable for MSW (-5% to +15.4% enhancement), unless conducted in the two-phase AD system. Microwave pre-treatment shows consistent performance in elevating the biogas production of MSW, but the energy consumption (114.24-8,040 kW_eh t^-1) and carbon emission footprint (59.93-4,217.78 kg CO₂ t^-1 waste) are relatively high. Chemical (∼0.43 kW_eh m^-3) and membrane-based (∼0.45 kW_eh m^-3) post-treatments are suggested to be a lower energy consumption approach for upgrading the biogas. The feasibility in terms of cost (scale up) and other environmental impacts (non-CO₂ footprint) needs to be further assessed. This study provides an overview to facilitate further development and extended implementation of AD.