Municipal anaerobic digesters for codigestion, energy recovery, and greenhouse gas reductions.

Codigestion of five wastes and municipal wastewater sludge was evaluated using full-scale testing. Synergistic, antagonistic, and neutral outcomes were observed depending on codigestate identity and concentration, highlighting the value of careful blending. Yeast waste resulted in notable synergism, increasing biogas production by over 50%, whereas aircraft deicing waste resulted in antagonism at high loadings and neutral outcomes at lower loadings. Restaurant waste codigestion resulted in neutral outcomes. The synergisim with yeast codigestates may have resulted from trace nutrients (i.e., iron, nickel, and cobalt) in the wastes that increased microbiological activity. Antagonist outcomes with deicing waste may have been the result of organic overload or inhibitory deicer constituents. Codigestion of wastes at the feed rates investigated was estimated to produce 0.50 ML/d of methane having an energy equivalent of 17 500 MJ/d. This was estimated to reduce net carbon dioxide emissions by 560 tonnes/y.     

Re-evaluating the asymmetric economic policy uncertainty,conventional energy,and renewable energy consumption nexus for BRICS

Environmental Science and Pollution Research - Economic policy uncertainty has increased throughout the world since the previous few decades. Moreover, economic policy uncertainty significantly...     

Economic complexity,ICT, biomass energy consumption,and environmental degradation: evidence from Iran

Economic complexity, biomass energy consumption, and information communication technology (ICT) have diverse impacts on energy consumption and carbon dioxide (CO₂) emissions. Nevertheless, analysis of these variable effects is not addressed in the previous literature; the antiqueness of this article is stuffing this gap. This study assessed the relationship between gross domestic product (GDP) per capita, biomass consumption, economic complexity index (ECI), ICT, and CO₂ emissions in Iran in 1994–2018. The autoregressive distributed lag (ARDL) model and the quantile regression (QR) econometric technique were used to investigate the factors affecting CO₂ emissions in the tails of the conditional distribution. The share of each influential factor was predicted through the variance decomposition analysis (VD) for the next 10 years. The empirical results showed a long-run relationship between the variables. So, the variables of biomass consumption, ECI, and ICT improve the quality of the environment in Iran by reducing CO₂ emissions, and the per capita GDP variable increases CO₂ emissions. Results suggest no evidence indicating the presence of environmental Kuznets curve (EKC); however, QR demonstrated the existence of EKCs in the lower quantiles of the conditional distribution. The ECI will have the most share to change the CO₂ emissions in the future. The income threshold should be determined at the turning point of the EKC to increase economic development. Moreover, investing in increasing biomass consumption is vital. Policymakers also need to consider strict added value for the export of products.

     

Assessing energy, environmental, and economic tradeoffs in intermodal freight transportation

This paper presents an energy and environmental network analysis model to explore tradeoffs associated with freight transport. The geospatial model uses an intermodal network built by the authors to connect various modes (rail, road, water) via intermodal terminals. Routes along the network are characterized not only by temporal and distance attributes, but also by cost, energy, and emissions attributes (including emissions of carbon dioxide, particulate matter, sulfur oxides, volatile organic compounds, and oxides of nitrogen). Decision-makers can use the model to explore tradeoffs among alternative route selection across different modal combinations, and to identify optimal routes for objectives that feature energy and environmental parameters (e.g., minimize carbon dioxide emissions). The model is demonstrated with three case studies of freight transport along the U.S. eastern seaboard.     

Carbon dioxide emissions,output, and energy consumption categories in Algeria

This study examines the relation between CO₂ emissions, income, non-renewable, and renewable energy consumption in Algeria during the period extending from 1980 to 2011. Our work gives particular attention to the validity of environmental Kuznets curve (EKC) hypothesis. The autoregressive distributed lag (ARDL) with break point method outcome demonstrates the positive effect of non-renewable type of energy on CO₂ emissions consumption. On the contrary, the results reveal an insignificant effect of renewable energy on environment improvement. Moreover, the results accept the existence of EKC hypothesis but the highest gross domestic product value in logarithm scale of our data is inferior to the estimated turning point. Consequently, policy-makers in Algeria should expand the ratio of renewable energy and should decrease the quota of non-renewable energy consumption.     

A bibliometric study about energy,environment, and climate change

Environmental Science and Pollution Research - Using the extended science citation index database (SCI) and social science citation index (SSCI) databases, this paper analyzed the characteristics...     

Consumption of energy from conventional sources a challenge to the green environment: evaluating the role of energy imports,and energy intensity in Australia

Environmental Science and Pollution Research - Conventional energy consumption such as coal, natural gas, and oil is a source of deteriorating environmental sustainability as well as a severe...     

Conversion of concentrated solar thermal energy into chemical energy

When a concentrated solar beam is irradiated to the ceramics such as Ni-ferrite, the high-energy flux in the range of 1500-2500 kW/m(2) is absorbed by an excess Frenkel defect formation. This non-equilibrium state defect is generated not by heating at a low heating-rate (30 K/min), but by irradiating high flux energy of concentrated solar beam rapidly at a high heating rate (200 K/min). The defect can be spontaneously converted to chemical energy of a cation-excess spinel structure (reduced-oxide form) at the temperature around 1773 K. Thus, the O(2) releasing reaction (α-O(2) releasing reaction) proceeds in two-steps; (1) high flux energy of concentrated solar beam absorption by formation of the non-equilibrium Frenkel defect and (2) the O(2) gas formation from the O(2-) in the Frenkel defect even in air atmosphere. The 2nd step proceeds without the solar radiation. We may say that the 1st step is light reaction, and 2nd step, dark reaction, just like in photosynthesis process.     

Modeling landfill gas potential and potential energy recovery from Thohoyandou landfill site,South Africa

ABSTRACT

The increase in solid waste generation has been a major contributor to the amount of Greenhouse gases (GHGs) present in the atmosphere. To some extent, a great chunk of these GHGs in the atmosphere is from landfill. This study assesses two theoretical models (LandGEM and Afvalzorg models) to estimate the amount of landfill gas (LFG) emitted from Thohoyandou landfill site. Also, the LFGcost Web model was used to estimate the cost and benefits of the implementation of an LFG utilization technology. The Thohoyandou landfill started operations in the year 2005 and it is proposed to reach its peak at approximately in the year 2026. The LandGEM calculates the mass of landfill gas emission using methane generation capacity, mass of deposited waste, methane generation constant and methane generation rate. Meanwhile, the Afvalzorg model determines the LFG emissions using the Methane correction factor, yearly waste mass disposal, waste composition, Degradation Organic Carbon, methane generation rate constant, LFG recovery efficiency. The study findings indicate that the methane (CH₄) and carbon dioxide (CO₂) emitted from the landfill estimated from LandGEM will peak in the year 2026 with values of 3517 Mg/year and 9649 Mg/year, respectively. Results from the Afvalzorg model show that CH₄ emission will peak in the year 2026 (3336 Mg/year). The LandGEM model showed that the total LFG, CH₄ and CO₂ emitted from the landfill between 2005 and 2040 are 293239.3 Mg/year, 78325.7 Mg/year and 214908.6 Mg/year, respectively. The simulation from the Afvalzorg model found that the CH₄ emitted from the years 2005– 2040 is 74302 Mg/year. The implementation of an LFG utilization technology was economically feasible from consideration of the sales of electricity generated and Certified Emission Reductions (CER) (carbon credits).     

Renewable energy demand,financial reforms,and environmental quality in West Africa

Environmental Science and Pollution Research - Sustainable Development Goal (SDG-7) stipulates the need for clean energy, reduced carbon dioxide emissions, prevention of environmental...     

Assessing environmental quality through natural resources,energy resources,and tax revenues

Environmental Science and Pollution Research - Developing countries have depleted their natural resources in economic interest to achieve high economic growth. Current urbanization patterns and...     

The roles of nuclear energy,renewable energy,and economic growth in the abatement of carbon dioxide emissions in the G7 countries

Environmental Science and Pollution Research - In the current century, the G7 countries have attached more importance to energy security, and have prioritized low-carbon sources which have...     

Urban energy mining from sewage sludge

This work showed that sewage sludge could be a strong candidate for biodiesel production. High lipid content (18–20%) with C_16?18-carbon range was experimentally identified and measured. These lipids from sewage sludge were converted into biodiesel via the transesterification reaction with MgO–CaO/Al₂O₃ derived from magnesium slag, and biodiesel conversion was ～98%. The experimental work enabled explaining that temperature is the main driving force for the transesterification reaction, which can be enhanced in the presence of CO₂. This also enables combination of esterification of free fatty acids and transesterification of triglycerides into a single process within 1 min in the temperature range of 350–500 °C. Sewage sludge residue after extracting lipids was also a good feedstock for recovering energy via thermo-chemical processes. The impact of CO₂ co-feed on the pyrolysis/gasification process of SS residue was also investigated in this work. The CO₂ injected into the thermo-chemical process remarkably increased the generation of CO by a factor of 2. Moreover, the introduction of CO₂ into the pyrolysis/gasification process enabled reducing condensable hydrocarbons (tar) by expediting cracking; thus, utilizing CO₂ as chemical feedstock for the gasification process not only leads to higher thermal efficiency but also has environmental benefits.     

The relevance of economic freedom for energy,environment, and economic growth in Asia-Pacific region

Environmental Science and Pollution Research - This paper investigates the relationship between energy intensity, economic freedom, and carbon emissions. The problem of environmental degradation,...     

Optimal sizing of different configuration of photovoltaic,fuel cell,and biomass-based hybrid energy system

Environmental Science and Pollution Research - The need for power is rising on a daily basis all across the world. Due to the finite supply of fossil fuels, it is critical to develop innovative...     

Impact of meteorology and energy structure on solvent extractable organic compounds of PM2.5 in Beijing, China

Twenty-eight PM2.5 samples collected in Summer (July 2002) and Winter (November 2002) at two sites in Beijing, China were analyzed using GC/MS to investigate the impact of meteorology and coal burning on the solvent extractable organic compounds (SEOC). The characteristics and abundance of the n-alkanes, polycyclic aromatic hydrocarbons (PAHs), n-fatty acids and n-alkanols were determined. Source identification was made using organic species as molecular markers. Semi-volatile compounds of alkanes and PAHs had much higher concentrations in winter than summer because of the large difference in the temperature between the seasons. Plant wax emission was a major contributor to n-alkanes in summer, but fossil fuel residue was a major source (>80%) in winter. The seasonal differences in the distribution of pentacyclic triterpanes clearly shows the impact of coal burning for space heating in winter. The yield of PAHs in winter (148 ng m(-3) at the urban site and 277 ng m(-3) at the suburban site) was six to eight times higher than that in summer and was found to be mainly from coal burning. Higher pollutant concentrations were measured at the suburban site than the urban site in winter due to the rapid expansion of the city limit and the relocation of factories from urban to suburban areas over the last two decades.     

推进节能减排促进生态环境协调发展的对策和建议

对嘉兴市南湖区节能减排现状进行调查分析的基础上,提出了南湖区目前存在产业结构调整缓慢、环保基础设施建设投入滞后、减排技术与设备落后、基础工作较薄弱,配套政策、制度体系、法制不健全、减排认识不到位等问题,从而针对问题提出了切实可行的对策与建议.     

dry coke quenching,air pollution and energy: a status report

Dry quenching of incandescent coke after it has been pushed from the coking ovens is a proved, reliable process that is presently being used in several industrialized countries. Foremost among dry quenching’s advantages are: (1) virtual elimination of air pollutants emitted during quenching; (2) elimination of potential water pollution associated with wet quenching; (3) improvements in the working environment; (4) saving substantial amounts of energy in usable forms; (5) producing more usable coke that is superior to wet-quenched coke. By continuously circulating inert gases through a cooling chamber that contains hot coke, dry quenching recovers waste-heat energy that can be used to produce steam, to produce electricity, to preheat combustion air, to preheat coal, to dry coal, and to preheat feed water supplied to fuel-fired boilers. The pay-out period on the capital investment (approximately $7,100,000) for an installation capable of processing 5500 tons of coke/day is less than four years.