Abstract

Mathematical models and simulation are becoming increasingly used tools in the optimization of wastewater treatment plants. In this paper, the use of these tools is presented for wastewater treatment plant upgrading. Two case studies are presented, which will be upgraded for tertiary treatment to achieve effluent total nitrogen and total phosphorous concentrations below 10 mg/l and 1 mg/l, respectively. The plant performance after upgrading was assessed by first designing the process model, before upgrading the model for future operation under dynamic influent conditions. Long-term simulations revealed some bottlenecks in the upgraded plant performance and thus helped to improve the plant designs. In one case the total volume of the reactors was increased subsequently, while in the other case tighter denitrification control or additional reject water treatment was proposed. These results indicate that mathematical models can be considered as valuable tools to complement the established wastewater treatment plant design procedures. Advantages are gained by simulating the operation under dynamic operating conditions, precise wastewater characterization, as well as adjustment of stoichiometric and kinetic parameters to a particular wastewater treatment plant operation.

Abstract

Added resistance in waves is the second-order steady force dependant on the ship motions. It significantly affects ship operability and causes speed loss. Therefore the required power and fuel consumption of a ship advancing in a seaway increase. In this paper, additional fuel consumption is approximated in relation to the increased resistance, i.e. the difference between the ship resistance in calm water and resistance while operating in waves. Ship advancing in regular head waves with different speeds is examined. Calm water resistance is calculated according to the potential flow theory and ITTC 1957 model-ship correlation line. The added resistance in waves is calculated using three-dimensional boundary element method based on the potential flow theory. Motion induced resistance due to heave and pitch motions as well as reflection induced resistance are taken into account. Therefore, overall assessment of added resistance in regular waves is achieved through evaluation of the ship drift forces and quadratic transfer function. The so-called near-field formulation is used to determine wave loads acting on the ship hull. Evaluation of increased fuel consumption is made on the basis of estimated added resistance for different speeds and wave frequencies. Correlation of fuel consumption with various wave frequencies that the ship may encounter in its voyage is obtained.

Abstract

The Journal of Sustainable Development of Energy, Water and Environment Systems - JSDEWES is an international journal dedicated to the improvement and dissemination of knowledge on methods, policies and technologies for increasing the sustainability of development by de-coupling growth from natural resources and replacing them with knowledge based economy, taking into account its economic, environmental and social pillars, as well as methods for assessing and measuring sustainability of development, regarding energy, transport, water, environment and food production systems and their many combinations. In total 32 manuscripts were published in Volume IV, all of them reviewed by at least two reviewers. The Journal of Sustainable Development of Energy, Water and Environment Systems would like to thank reviewers for their contribution to the quality of the published manuscripts.

Abstract

The number of research papers related to solar cells field is increasing rapidly. It is hard to grasp research trends and to identify emerging research issues because of exponential growth of publications, and the field’s subdivided knowledge structure. Machine learning techniques can be applied to the enormous amounts of data and subdivided research fields to identify emerging researches. This paper proposed a prediction model using a machine learning approach to identify emerging solar cells related academic research, i.e. papers that might be cited very frequently within three years. The proposed model performed well and stable. The model highlighted some articles published in 2015 that will be emerging in the future. Research related to vegetable-based dye-sensitized solar cells was identified as the one of the promising researches by the model. The proposed prediction model is useful to gain foresight into research trends in science and technology, facilitating decision-making processes.

Abstract

In the worldwide market of particleboard production, the use of alternative raw materials is increasing, due to high demand and lack of traditional raw material, despite efforts of reforestation. In Brazil, the main agricultural commodity is sugarcane due to the copious production of sugar and ethanol. In the state of São Paulo alone approximately 140 million tons of sugarcane bagasse are produced every year, from which around 70% is burned for energy production, not adding value to the residue and generating pollution to the environment; and the other 30% is sold for composting. The objective of this work is to add value to the sugarcane bagasse by using it as a raw material for particleboard production to be employed as flooring in the area of civil construction. To achieve this, the present research characterized the physical and mechanical characteristics of the particleboards with the following alternative raw materials: sugarcane bagasse and leaves of bamboo. Particleboards were produced to reach high density (0.8 g/cm3) using the resin (bi-component) polyurethane castor oil. Tests for abrasion, roughness and resistance to denting and wear (Janka hardness) verified that the addition of leaves of bamboo in the mixtures, contrary to what was expected, did not confer a greater degree of resistance to the particleboards. Lastly, the results showed that sugarcane bagasse is a viable raw material alternative for the production of particleboards, intended to be used as products and flooring.

Abstract

The aim of this study was to develop a real-time dynamic simulator of a power grid with power plant and battery model. The simulator was used to investigate the frequency control characteristics of a megawatt-scale high-capacity energy storage system connected to the electric power grid. In this study, a lithium-ion secondary battery was chosen as one of the batteries for a grid-connected model. The dynamics of the model was analysed in both steady and transient states. The frequency control system of the battery model plays a role in regulating the grid frequency by controlling the power of energy storage systems according to process variables and grid frequencies. The power grid model based on the current power network of South Korea, included power plants, substations and power demands. The power supply is classified by the type of turbine generator as thermal, nuclear, hydro power, pumped power storage, combined power plants and batteries, including high-capacity energy storage systems rated for a maximum of 500 MW. This study deals with an installed capacity of 87.17 GW and peak load of 77.30 GW in the Korean power grid. For 24 hours of operation, the maximum and minimum power outputs were simulated as 61.59 GW and 46.32 GW, respectively. The commercialized real-time dynamic simulation software ProTRAX was used. The simulation was conducted to observe the operation characteristics of the frequency control system during a breakdown of power plants, as well as under governor-free operation, auto generation control operation, and with the battery energy storage system connected. The results show that the model is valid for each power plant breakdown simulation. They also confirm that the output power and frequency controls of the battery operated well during simulations.

Abstract

Brazil as well as the rest of the world, faces a major challenge related to the electricity sector, to meet the growing demand with energy production from renewable sources. Many hydroelectric plants are being implemented, especially in the northern region of Brazil, but its environmental impacts are yet unknown. Energy produced by hydropower plants has been considered totally renewable and clean, but more recent studies describe analysis pointing to the existence of emissions by hydroelectric plants, especially if a lifecycle approach is considered. Thus, the objective of this study is the investigation of environmental impacts of the construction, operation and decommissioning of a hydroelectric power station based on life cycle assessment. The main focus is the Curuá-Una hydropower plant that is located in the Amazon forest in northern Brazil, in Santarém municipality (Pará state).

Abstract

To assess cost, time investment, energy consumption and carbon emission of manufacturing on a per-piece basis, a bottom-up approach for aggregating a real-time product footprint is proposed. This method allows the evaluation of the environmental impact of a batch or even single product using monitoring or simulation data. To analyze the infrastructure, the production plant is decomposed into modules that are in relation to each other via inputs and outputs. Distinguishing between modules for production, logistics, energy system, buildings and auxiliary systems, the different approaches for distributing resource consumption between the products are presented. Special attention is paid to typical scenarios that occur in production plants and problems that may arise from them. For example, the incorporation of standby-, setup- and ramp-up times, the energy consumption of the administration and the allocation of different products and by-products manufactured at a machine are taken into account.

Abstract

This research describes the potential study on the impact of energy improvements of existing campus buildings by on-site energy management and operational strategies. The focus buildings in the campus were mainly built in the 1960s, and therefore it is time to carry out renovation work. In conjunction with the renovations, the aim is to improve the energy efficiency of the buildings, and to develop the functionality of the properties to meet the current requirements. Thus, in this study, the potentials of on-site energy generation and sharing in the cluster of campus buildings in Finland were studied. By means of optimisation method, the optimal combined heat and power systems capacity distribution and operation mode for minimizing annual primary energy consumption were simulated. The results show that the integration of buildings has an advantage of 23% of primary energy reduction for on-site energy management as compared with the present situation. Consequently, integrating buildings and optimizing on-site energy management can be one of effective strategies for minimizing primary energy consumption. Furthermore, the study to improve operation strategies of building service systems considering current space use in the buildings clarified that up to 13% of total energy use reduction is expected. The research work also proposes a way of providing environmental information to increase awareness of building energy usage in the campus.

Abstract

without any restrictions for the following generations. In these concepts the wind energy and wave/ocean current energy are important factors as the description and the prognosis of waves and currents is a complex issue, especially offshore. For the estimation of the average annual wind speed and thus the energy production of offshore windfarms, it is imperative to know the exact wind conditions at each project site. Suitable prognosis methods are either missing so far, or not accurate enough, or at beta stage. The only possibility to achieve exact information about the offshore conditions is a metocean station consisting of wind and wave sensors. These met stations can be lattice masts mounted on monopiles or buoys equipped with meteorological sensors, both in combination with wave sensors to include all important parameters. Though conventional metocean stations are far more common, established and are measuring data of high quality, cheaper and more flexible solutions such as the likes of floating light detection and ranging are about to be used during the operation of wind farms. This article explains currently used methods of offshore measurements with respect to wind and wave and compares it with reanalysis data. This data has advantages in comparison to measurements from conventional metocean stations, but cannot be used independently. This article proves that using solely reanalysis data is not possible, that measurements offshore are still necessary and that its operation helps in improving the performance of offshore wind farms.

Abstract

Bay leaves are used for flavoring in cold drinks production, in bakery goods, sauces, confectionary products and liquors. The waste generated from these sources has been valorized by attempting the remediation of waste water. Hence, adsorption of toxic metals onto Bay leaves has been investigated after optimizing the experimental parameters, namely the pH, contact time, adsorbent and Zn(II) concentrations as well as the temperature of the equilibrium mixture (consisting of the metal solution in contact with the adsorbent). The participation of the constituent functional groups, of the adsorbent, was ascertained with Fourier transform spectroscopic studies. The mode of adsorption was examined by employing important isotherm models, namely Langmuir, Freundlich and Dubinin-Radushkevich models. The adsorption process was found to follow pseudo-first order kinetic model and also followed the intraparticle diffusion up to 60 minutes of contact time. The thermodynamic parameters suggest the spontaneous nature of adsorption.

Abstract

This paper presents findings from initial fieldwork studies of sustainable energy community development methodologies in two islands in Denmark and one rural village in Ireland. The main goals of this study were to determine the enablers and barriers to their successful development and to assess the successful elements of these previously implemented sustainable energy community development methodologies. The study involved extensive semi-structured interviews with the managers of the sustainable energy community projects and comprehensive site visits of each project. The evidence presented in this paper indicates that social barriers are interconnected and often reinforce each other. This article suggests that a comprehensive understanding of how barriers can be transformed into enablers supports the successful development of sustainable energy communities at local level in Europe. The findings in this research indicate that although each of the sustainable energy communities studied did not have any specific implementation framework developed for their projects, many of the successful tools and methodologies used across all communities were similar. The significant contribution of this work is the illumination of key factors influencing the successful development of sustainable energy communities in Ireland and Europe.

Abstract

The study deals with sorption and diffusion behaviour of strontium in Czech bentonite B75. The study is a part of a research on reactive transport of radioactive contaminants in barrier materials of a deep geological repository of radioactive waste in the Czech Republic. Series of sorption and diffusion experiments with Sr and non-activated Ca bentonite B75 produced in the Czech Republic were performed in two background solutions (CaCl2 and NaCl). On the basis of sorption batch experiments the kinetics of strontium sorption on bentonite was assessed and the sorption isotherms for various experimental conditions were obtained. As a result of performed diffusion experiments the parameters of diffusion (i.e. effective diffusion coefficient De and apparent diffusion coefficient Da) were determined. The observed discrepancies between sorption characteristics obtained from the sorption and diffusion experiments are discussed.

Abstract

When approaching a conventional wind turbine, the air flow is slowed down and widened. This results in a loss of turbine efficiency. In order to exploit wind or water flow power as effectively as possible, it was suggested that the turbine should be placed inside a shroud, which consists of 4 wing-shaped surfaces. Two internal air foils improve the turbine performance by speeding up the flow acting on the turbine blades, two external wings create a field of low pressure behind the turbine, thus, helping to draw more mass flow to the turbine and avoid the loss of efficiency due to flow deceleration. The system accumulates kinetic energy of the flow in a small volume where the smaller (and therefore, cheaper) turbine can be installed. A smaller system can be installed inside the bigger one, which would help to accumulate even more kinetic energy on the turbine. This method implies kinetic energy summation with local flow redistribution. Both experiments and CFD simulations demonstrate a significant increase in velocity and generated mechanical power in comparison to those for a bare turbine.

Abstract

A quarter of the total primary energy demand in the European Union is met by natural gas. Synthetic natural gas produced through biomass gasification can contribute to a more sustainable energy supply system. A chain analysis of the energetic performance of synthetic natural gas where the upstream, midstream and downstream part are included has not been found in literature. The energy performance of the possible large-scale application of synthetic natural gas is therefore unsure. A model was designed to analyse the performance of the biomass to synthetic natural gas chain and to estimate the effect of 1% synthetic natural gas in the energy system. A break-even distance is introduced to determine whether it is energetically feasible to apply pretreatment. Results show that torrefaction and pelleting are energetically unfeasible within the European Union. Emissions can be reduced with almost 70% compared to a fossil reference scenario. Over 1.2 Mha is required to fulfil 0.25% of the total primary energy demand in the European Union.

Abstract

The simultaneous rise in commodity prices and the global production of biofuels, between 2007 and 2008, strengthened discussions, which persist currently, about the competition of land use between biofuel production and food production. The objective of this paper is to compare and evaluate the arguments from both sides. The methodology used was an analysis of the relevant and comprehensive reports and manuscripts on the topic, comparing them to the available data from international organizations and agencies. Biodiesel received special attention in this analysis. The conclusion is that hunger and poverty problems are due to structural and historical roots and they do not have a cause-effect relationship with biodiesel production. In fact, the production of biodiesel, under specific regulatory and production conditions, can be a driver of economic development improving energy security and promoting social inclusion in poor countries, which still have land available for agriculture.

Abstract

The arsenic occurrence in the water constitutes a serious world health concern due to its toxicity. Depending on the intensity and duration of exposure, this element can be acutely lethal or may have a wide range of health effects in humans and animals. In Argentina, the origin of arsenic is mainly natural, and related to different geological processes. The Argentinean concern about arsenic and its influence on human health dates back to the previous century. The disease ascribed to arsenic contamination was called ‘chronic regional endemic hydroarsenism’. It is produced by the consumption of water with high levels of this element. In our study, we focused in La Matanza district, a very populated site in the Buenos Aires Province. An increasing concern of the inhabitants of the area regarding health problems was detected. In order to establish a full view of arsenic exposure in the area, several matrices and targets were analyzed. As matrices, water and soil samples were analyzed. As targets, canine and human hair was studied. The aim of this study was to investigate acute and chronic exposure to arsenic of La Matanza inhabitants.

Abstract

The Urban Wastewater Treatment Directive 91/271/EEC introduced a series of measures for the purpose of protecting the environment from the adverse effects of effluent discharge from wastewater treatment plants. There are environmental costs associated with attaining the required level of water quality set out in the directive such as greenhouse gas emissions due to energy production, and ecotoxicity from sludge application to land. The goal of this study is to assess the environmental costs in an Irish context, focusing specifically on the effects of variation in scale and discharge limitation. Life cycle assessment is the analytical tool used to evaluate the environmental impact. The life cycle impact assessment methodology developed by the Centre of Environmental Science, Leiden University (2010) has been adopted and implemented using GaBi 6.0 life cycle assessment software. Two plants of varying size and location were chosen for the study. The study found that energy consumption and sludge application to land are the largest contributors to the overall environmental impact associated with the treatment process at both plants. Economies of scale were observed in energy usage during secondary aeration.

Abstract

The problem of modernization of the heat module with two-stage mixing scheme connection of hot water supply by installations of the heat pump during interheating period is considered. Heating water of the in-house circuit of the building heating system is used as a heat source for heat pump. The district cooling of the residential areas is possible through the heaters during the summer. R600 refrigerant is chosen for heat pump for its environmental-friendliness and low-pressure of evaporation and condensation. The economic calculation is made for interheating period comparing the operation with and without heat pump. This paper advances selection of optimum amount of heat to be recovered during low potential heat utilisation and targets for heating and cooling capacities.

Abstract

In this study, an efficient method for using pulsed plasma to produce hydrogen from ammonia was developed. An original pulsed plasma reactor with a hydrogen separation membrane was developed for efficient hydrogen production, and its hydrogen production performance was investigated. Hydrogen production in the plasma was affected by the applied voltage and flow rate of ammonia gas. The maximum hydrogen production flow rate of a typical plasma reactor was 8.7 L/h, whereas that of the plasma membrane reactor was 21.0 L/h. We found that ammonia recombination reactions in the plasma controlled hydrogen production in the plasma reactor. In the plasma membrane reactor, a significant increase in hydrogen production was obtained because ammonia recombination reactions were inhibited by the permeation of hydrogen radicals generated in the plasma through a palladium alloy membrane. The energy efficiency was 4.42 mol-H2/kWh depending on the discharge power.