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Abstract A novel integrated energy system based on a geothermal heat source and a liquefied natural gas heat sink is proposed in this study for providing heating, cooling, electricity power, and drinking water simultaneously. The arrangement is a cascade incorporating a flash-binary geothermal system, a regenerative organic Rankine cycle, a simple organic Rankine cycle, a vapor compression refrigeration cycle, a regasification unit, and a reverse osmosis desalination system. Energy, exergy, and exergoeconomic methods are employed to analyze the suggested system. A parametric study based on decision variables is carried out to better assess the system performance. Four different multi-objective optimization problems are also carried out. At the most excellent trade-off solution specified by the TOPSIS method, the system attains 29.15% exergy efficiency and 1.512 $/GJ total product cost per exergy unit. The main output products are consequently calculated to be 101.07 kg/s cooling water, 570.44 kW net output power, and 81.57 kg/s potable water.

[EN] Knowledge on the effects of climate change in a system can contribute to the better management of its water and energy resources. This study evaluates the consequences of alterations in the rainfall and temperature patterns for a hydroelectric plant. The methodology adopted consists of four steps. First, a hydrological model is developed for the chosen basin following a semi-distributed and conceptual approach. The hydrological model is calibrated utilizing the optimization algorithm Shuffled Complex Evolution University of Arizona (SCE-UA) and then validated. Secondly, a hydropower model is developed fora hydroelectric plant of the chosen basin. The hydropower model is adjusted to the physical characteristics of the plant. Thirdly, future climate scenarios are extracted from the literature for the studied area. These scenarios include quantitative and seasonal climate variations, as well as different initial reservoir levels. Fourth, the hydrological-hydropower model is simulated for 52 scenarios and the impact of changes in the rainfall and temperature patterns for hydropower generation is evaluated. For each scenario, the water storage in the reservoir and energy produced by the plant are analyzed. The financial impact for extreme scenarios is presented. The methodology is applied to the Tres Marias hydroelectric plant at the upper SAo Francisco river basin (Brazil) and it can be replicated to any other hydropower system. The results show that extreme positive values predicted for rainfall will likely not cause issues to the plant, considering a moderate rise in temperature. However, negative predictions for rainfall, regardless of changes in temperature, should be an alert to the authorities responsible for water and energy resources management. This study was funded by the Sao Paulo Research Foundation (FAPESP -grant #2018-00016-8), European Commission (EBW+ program), and National Council for Scientific and Technological Development (CNPq). The authors thank Companhia Energetica de Minas Gerais S.A. (CEMIG), Agencia Nacional de Aguas (ANA), Instituto Nacional de Meteorologia (INMET), and Camara de Comercializacao de Energia Eletrica (CCEE) for kindly providing the data needed to carry out this research. The authors also thank the developers of RS Minerve, computational tool utilized in this research, and Espaco da Escrita -Pro-Reitoria de Pesquisa (PRP/UNICAMP), for the language services provided.

Annually, 115.000 tons of plastic tableware are used in Italy. The end of life of these objects is particularly troubled because no efficient way of recycling or reusing exist. Studies performed by the European Union demonstrate that about 80% of sea waste is made of plastic, representing a danger to human health and ecosystem. The aim of this paper is to analyse substitutes to disposable plastic tableware using the Life Cycle Assessment methodology. The alternatives are objects made of bio compostable plastic, both disposable and reusable. This article compares single-use and multi-use tableware made of a Polylactic acid (PLA) - Polybutylene succinate (PBS) blend with traditional disposable tableware made of polypropylene and of polystyrene. In order to perform an effective assessment, the objects are grouped in place settings, each made of a cup, a plate and cutlery. The use of tray mat and napkin is also taken into account. It was assumed that the fossil-based items are sent to landfill whereas the bio-based ones are sent to a compost plant. The functional unit chosen was “the service of 1000 meals”. The impact categories taken into account are Global Warming 100a, Ozone Depletion, Ozone Formation (Vegetation), Acidification, Aquatic Eutrophication, Human Toxicity water and Ecotoxicity water chronic. The results show that the compostable table sets have lower impact than the sets made of fossil-based plastic in all the categories except in Ozone Depletion and in Aquatic Eutrophication. In the categories of Human Toxicity water and Ecotoxicity water chronic, fossil-based materials have higher impact than multi-use one mainly due to the landfill scenario chosen as end of life. Disposable and reusable systems give a different contribution to total impact in different life stages. For disposable systems, the production and the end of life are the critical stages in terms of environmental burden, whereas for reusable systems washing is the most impactful phase. Further improvements can be obtained in the production of bio-based materials by using renewable energy to power the facilities whereas the washing phase can be improved by adopting certified ecopower. The impact of the reusable system strongly depends on the assumptions made on the number of reuses and on the washing modality.

A dynamic model was developed for representing the abatement of sulfates and metals in column reactors inoculated with sulfate reducing bacteria. The model framework includes both bioactive mechanisms (bioreduction of sulfates and bioprecipitation of metals) and passive abiotic mechanism (sorption onto the column filling). Sorption capacities of column filling material were determined by dedicated tests of sulfate and cadmium removal. These experimental data implemented in model framework denoted that before steady state sorption mechanism could predominate over bioactive mechanism. Sensitivity analysis confirmed that, varying sorption and bioreduction parameters in typical range of laboratory scale systems, sorption cannot be neglected before steady state. An operative equation was obtained by literature data and model simulations showing that in the majority of works reported in the literature the operational times used for column experiments are not sufficient to saturate column sorption capacity. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 70–80, 2014

The physical and biological mechanisms of attached-biomass growth were analyzed and a steady-state model was proposed to determine the soluble carbonaceous removal in an RBC unit for different organic loading rates in the reactor. The objective of the model was the prediction of the organic loading rate corresponding to the maximum removal capacity in the system. A system of equations was solved where the influent soluble carbonaceous substrate concentration was the main variable. Monod's rate law was used for the growth of microorganism: the soluble carbonaceous substrate was the limiting substrate. Endogenous decay was neglected. The influence of disk rotational speed on the RBC removal capacity was investigated, the disk rotational speed being a parameter acting on oxygen transfer in the biofilm. The criteria for the evaluation of the kinetic parameter in the model were proposed.

Water shortage and its interconnected and integrated management is one of the life crises in recent years. Factors such as population growth, plurality of population needs, traditional farming methods, climate change, and water waste are among the contributing factors to this crisis. The complexity of water sources and consumption systems makes the management and decision-making related to this resource very difficult. This research aims to study the effective factors in the water sources and consumption system of Rafsanjan city and suggests a simulated model of water shortage and its causes. In this research, water shortage crises were simulated using system dynamics. Important variables of the water shortage crisis are identified and optimized using the Design of Experiments (DOE) method. Vensim software was considered to illustrate the simulations of five scenarios aiming at better managing water resources and dealing with the water shortage crisis in this city.

A pure culture of Amaricoccus kaplicensis was aerobically cultured at a long culture residence time (Theta(C)>12d), under periodic acetate feeding in a sequencing batch reactor (SBR). The cycle length and, correspondingly, the volumetric organic load rate (vOLR) were varied in the range 4-24h and 0.76-0.12gCODl(-1)d(-1), respectively. The transient response of the microorganism to the acetate spike was investigated throughout batch tests, as a function of SBR cycle length and vOLR. In all tested conditions, a rapid transient response was observed, mainly due to acetate storage in the form of polyhydroxybutyrate, since growth (production of active biomass) played a minor role. Apart from this general trend, the maximum rates under transient conditions increased as the cycle length increased from 4 to 24h. In the SBR, the longest cycle also caused a decrease in floc size and settleability as well as an increase in the observed yield. The observed effect of SBR operating conditions on the physiological state of cells and their related transient response may have great significance on the performance of full scale activated sludge processes.

Abstract The aim of this work was to provide a complete exergy and energy analysis of three biogas upgrading technologies: amine scrubbing, water scrubbing and membrane separation processes. Biogas production and treatment represents a key-process for the application of Circular Economy principles, since allows to reuse/reconvert industrial by-products or agro-industrial waste in a product that can be used in different energy demanding sectors, after proper cleaning and upgrading processes. The three technologies here reported have been implemented in Aspen Plus flowsheets, and were used to upgrade a biogas to biomethane, meeting the UNIT/TS 11537:2019 standards for Biogas to be injected in the gas grid. Each units of all the simulated processes have been analysed calculating total exergy feed, total exergy produced and exergy loss, distinguishing that lost for irreversibility and as waste. Water scrubbing was characterized by the highest values of exergy efficiency (94.5%) and methane recovery (99%), whereas the lowest exergy efficiency belonged to membrane separation (90.8%) that returned also the largest specific energy consumption (0.94 kWh/m3 STP). Conversely, amine scrubbing was characterized by the lowest specific energy consumption value (0.204 kWh/m3 STP) but by an exergy efficiency of 91.1%.