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Among the sustainable initiatives for renewable energy technologies, anaerobic digestion (AD) is a potential contender to replace fossil fuels. The anaerobic co-digestions of goat manure (GM) with sorghum (SG), cotton gin trash (CGT), and food waste (FW) having different mixing ratios, volumes, temperatures, and additives were optimized in single and two-stage bioreactors. The biochemical methane potential assays (having different mixing ratios of double and triple substrates) were run in 250 mL serum bottles in triplicates. The best-yielding ratio was up-scaled to fabricated 2 L bioreactors. The biodegradability, biomethane recovery, and process efficacy are discussed. The co-digestion of GM with SG in a 70:30 ratio yielded the highest biomethane of 239.3 ± 15.6 mL/gvs, and it was further up-scaled to a two-stage temperature-phased process supplemented with an anaerobic medium and fly ash (FA) in fabricated 2 L bioreactors. This system yielded the highest biomethane of 266.0 mL/gvs, having an anaerobic biodegradability of 67.3% in 70:30 GM:SG co-digestion supplemented with an anaerobic medium. The BMP of the FA-amended treatment may be lower because of its high Ca concentration of 205.74 ± 3.6. The liquid fraction of the effluents can be applied as N and P fertigation. The Ca concentration was found to be 24.3, 25.1, and 6.3 g/kg in GM and GM:SG (TS) and SG solid fractions, respectively, whereas K was found to be 26.6, 10.8, and 7.4 g/kg. The carbon to nitrogen ratio of solid fraction varied between 2.0 and 24.8 for return to the soils to enhance its quality. This study involving feedstock acquisition, characterization, and their anaerobic digestion optimization provides comprehensive information and may assist small farmers operating on-farm anaerobic digesters. [ABSTRACT FROM AUTHOR]

Global energy problems range from the increasing cost of fuel to the unequal distribution of energy resources and the potential climate change resulting from the burning of fossil fuels. A sustainable nuclear energy would augment the current world energy supply and serve as a reliable future energy source. This research focuses on Monte Carlo simulations of pressurized water reactor systems. Three different fuel grades - mixed oxide fuel (MOX), uranium oxide fuel (UOX), and commercially enriched uranium or uranium metal (CEU) - are used in this simulation and their impact on the effective multiplication factor (Keff) and, hence, criticality and total radioactivity of the reactor core after fuel burnup analyzed. The effect of different clad materials on Keff is also studied. Burnup calculation results indicate a buildup of plutonium isotopes in UOX and CEU, as opposed to a decline in plutonium radioisotopes for MOX fuel burnup time. For MOX fuel, a decrease of 31.9% of the fissile plutonium isotope is observed, while for UOX and CEU, fissile plutonium isotopes increased by 82.3% and 83.8%, respectively. Keff results show zircaloy as a much more effective clad material in comparison to zirconium and stainless steel.

In order to solve the energy crisis and reduce emissions of greenhouse gases (GHG), renewable energy resources are exploited for power generation. Because lignocellulosic biomass resources are abundant and renewable, various technologies are applied to using lignocellulosic biomass to derive biofuel and electricity. This paper focuses on power generation from lignocellulosic biomass and comparison of the effects of different feedstocks, transportation, and power generation technologies evaluated through life cycle assessment (LCA). The inputs and boundaries of LCA vary with different feedstocks, such as forestry wood, agricultural residues, and fast-growing grass. For agricultural residues and fast-growing grass, the transportation cost from field to power plant is more critical. Three technologies for power generation are analyzed both with and without pelletization of lignocellulosic biomass. The GHG emissions also vary with different feedstocks and depend on burning technologies at different plant scales. The daily criteria pollutant emissions of power generation from different lignocellulosic biomass were evaluated with a life cycle assessment model of GREET.net 2014. It is concluded that bio-power generation is critical with the urgency of greenhouse effects. [ABSTRACT FROM AUTHOR]

Environmental sustainability, defined as the responsibility to protect the global ecosystem in a holistic way, has become an integral factor of city strategies. Designing and implementing environment-friendly solutions to make the standard of living in cities better is indispensable for present and future generations. This article's main objective is to identify the most environmentally friendly urban logistics measures from the perspective of urban transport system stakeholders. A multi-method approach was implemented to achieve the article's main findings. Firstly, the literature review provided the basics for designing the research framework. Then, a three-layer methodological approach was used: The first layer included designing and carrying out the case study approach; the second layer comprised a Delphi study involving interviews with urban logistics stakeholders; and the third layer included analyzing the voices of Delphi interviewees to assess which urban logistics measures are the most important for them. The study provides an initial insight into the opinions of stakeholders for a general audience, but at the same time, also presents specific, detailed views of Tricity urban space users and decision-makers. Significant differences in opinions were observed and confirmed in the interviewed group. This study can contribute to the scientific discussion about the stakeholders' analysis of urban logistics goals. [ABSTRACT FROM AUTHOR]

The adsorption of four volatile organic compounds (1,4-dichlorobenzene, 1,2-dichloroethane, 1,2,2-trichloroethane and 1,1,2,2,-tetrachloroethane) on three soil types from a Superfund site (Petroprocessors Inc) in Baton Rouge, LA was studied with the purpose of obtaining an overall correlation for inclusion in a groundwater transport model being developed for site remediation. The soil-water partition constant,Kd was determined using a standard ASTM procedure (E-1195-87). Using the data for different soil types (fraction organic carbon between 0.11% and 1.13%) and different mineral surface areas (7 to 45 m2/g), the organic carbon contribution (Koc)and the mineral matter contribution (Kmin) to the partition constant were determined. The soils obtained were either from the Pleistocene period or recent shallow deposits at the site. Both log Koc and log Kmin were linearly correlated to logKow, the octanol-water partition constant. This data provided the basis for obtaining a general correlation for Kd on different soil types at the site. The predicted values were in agreement with that for a composite soil from the same site. The desorption of compounds from the high clay soil after the 24 hour adsorptionperiod was observed to show a biphasic behavior, namely, an easily desorbed fraction and a desorption resistant fraction. The easily desorbed fraction was found to be satisfactorily predicted using the conventional Kd as obtained from the adsorption experiment. The slowly desorbing fraction had a time constant of several weeks. Theconcentration in the desorption resistant compartment was found to be dependant on the initial amount of contaminant available for adsorption. The aqueous phase concentration in equilibrium with the desorption resistant fraction was found to be approx. 8 microg/L for dichlorobenzene and approx. 12 microg/L for dichloroethane. [ABSTRACT FROM AUTHOR]