Geothermal Resources for Development in Central America -Social and Economic Valuation, Present Use and Future Opportunities

ABSTRACT In Central America, growing population, expanding economies and new markets, result in an annual rate of the electricity demand of about 6% through the year 2020. This, together with the fluctuations in the world energy markets, require to develop more reliable domestic environmentally sound electrical systems, which are precondition for a sound social and economic development of the region

On-farm energy use in the grain and horticultural industries

Agriculture and the related primary industry requires energy as an important input. Energy is needed to a differing extent in all the stages of the agri-food chain. In this paper, on-farm energy use in the grain and horticultural industries is evaluated. It is found that the energy use varies significantly with the farm enterprises and also the farming systems, including irrigation and heating/cooling methods. The total direct on-farm energy use for grain grown under dryland conditions with no tillage may be as low as 0.35 GJ/ha, while for horticultural products, the direct on-farm energy use may reach up to 20000 GJ/ha for tomatoes grown in greenhouses. The large variation of energy uses may indicate the significant opportunities for reducing energy use in these industries

On-farm energy use in the dairy industries

Dairying is one of largest agricultural industries in Australia. This paper reviews the on-farm energy use in various dairy operations. It is found that the total direct on-farm energy needed to produce one kilogram of milk varies between 0.41-0.83 MJ/kg milk in Australia. This is in comparison with 0.19-2.47 MJ/kg milk overseas. The differences in energy uses are mainly due to different farming systems and technologies adopted and also different analysis methods employed. The large variation of energy uses indicates the significant opportunities for reducing energy use

An assessment of direct on-farm energy use for high value grain crops grown under different farming practices in Australia

Several studies have quantified the energy consumption associated with crop production in various countries. However, these studies have not compared the energy consumption from broad range of farming practices currently in practice, such as zero tillage, conventional tillage and irrigated farming systems. This study examines direct on-farm energy use for high value grain crops grown under different farming practices in Australia. Grain farming processes are identified and “typical” farming operation data are collected from several sources, including published and unpublished literature, as well as expert interviews. The direct on-farm energy uses are assessed for 27 scenarios, including three high value grain crops―wheat, barley and sorghum―for three regions (Northern, Southern and Western Australia) under three farming conditions with both dryland (both for conventional and zero-tillage) and irrigated conditions. It is found that energy requirement for farming operations is directly related to the intensity and frequency of farming operations, which in turn is related to tillage practices, soil types, irrigation systems, local climate, and crop types. Among the three studied regions, Western Australia requires less direct on-farm energy for each crop, mainly due to the easily workable sandy soils and adoption of zero tillage systems. In irrigated crops, irrigation energy remains a major contributor to the total on-farm energy demand, accounting for up to 85% of total energy use

Arsenic in the Iberoamerican region. The IBEROARSEN Network and a possible economic solution for arsenic removal in isolated rural zones

In this work, a short description of the problematic of arsenic in Iberoamerica will be given, indicating the affected geographical regions and their incidence on the quality of life of the populations. In Argentina, Chile, Bolivia, Peru, Ecuador and Mexico, at least 4 million people depend on water sources with toxic concentrations of arsenic. While in these countries the problem is known since decades, in Uruguay, Brazil, Nicaragua, Honduras and El Salvador, the problem has been detected or investigated only in last years, and, in other Latinamerican countries, the studies began only recently. In Spain and Portugal the problem of As is becoming increasingly important. The presence of As in drinking waters, together with poverty and malnutrition, causes the incidence of CERHA (chronic endemic regional hydroarsenicism, HACRE in Spanish), an illness that provokes serious problems like skin lesions and even cancer. The activities of the IBEROARSEN Network of the CYTED Program, an Iberoamerican project that aims at the interconnection of groups devoted to arsenic R&D, trying to find solutions to this problem in the region, will be described. In addition, results of evaluation of the efficiency of two very simple low-cost methods for As removal in plastic bottles using solar light, one of them using heterogeneous photocatalysis with TiO2 immobilized on the walls followed by iron addition, and another one based on the use of zerovalent iron, which employs very cheap materials, are presented. The study was performed with synthetic and natural waters of rural, isolated, poor populations, not connected to the drinking water network of the provinces of Tucumán and Santiago del Estero, Argentina. For HP tests, synthetic as well as natural samples containing arsenic placed in bottles internally covered by a TiO2 layer and exposed to solar or artificial UV light followed by an addition of an iron source resulted in As concentration well below the national standards. For ZVI tests, iron wool demonstrated to be a better iron source than packing wire for As removal. Solar irradiation, in synthetic as well as in natural samples, seems to definitively improve As removal, avoiding the use of high amounts of iron. Although both HP and ZVI gave similar results, the use of the first one could be superior due to the ability of removing simultaneously As, organic matter, toxic metals and microbiological contamination

Towards a sustainable energy technologies based agriculture

Sustainability in agriculture and associated primary industries, which are both energy-intensive, is crucial for the development of any country. Increasing scarcity and resulting high fossil fuel prices combined with the need to significantly reduce greenhouse gas emissions, make the improvement of energy efficient farming and increased use of renewable energy essential. This book provides a technological and scientific endeavor to assist society and farming communities in different regions and scales to improve their productivity and sustainability. To fulfill future needs of a modern sustainable agriculture, this book addresses highly actual topics providing innovative, effective and more sustainable solutions for agriculture by using sustainable, environmentally friendly, renewable energy sources and modern energy efficient, cost-improved technologies. The book highlights new areas of research, and further R&D needs. It helps to improve food security for the rapidly growing world population and to reduce carbon dioxide emissions from fossil fuel use in agriculture, which presently contributes 22% of the global carbon dioxide emissions. This book provides a source of information, stimuli and incentives for what and how new and energy efficient technologies can be applied as effective tools and solutions in agricultural production to satisfy the continually increasing demand for food and fibre in an economically sustainable way, while contributing to global climate change mitigation. It will be useful and inspiring to decision makers working in different authorities, professionals, agricultural engineers, researchers, and students concerned with agriculture and related primay industries, sustainable energy development and climate change mitigation projects

Selective removal of arsenic in water: A critical review

Selective removal of arsenic (As) is the key challenge for any of As removal mechanisms as this not only increases the efficiency of removal of the main As species (neutral As(III) and As(V) hydroxyl-anions) but also allows for a significant reduction of waste as it does not co-remove other solutes. Selective removal has a number of benefits: it increases the capacity and lifetime of units while lowering the cost of the process. Therefore, a sustainable selective mitigation method should be considered concerning the economic resources available, the ability of infrastructure to sustain water treatment, and the options for reuse and/or safe disposal of treatment residuals. Several methods of selective As removal have been developed, such as precipitation, adsorption and modified iron and ligand exchange. The biggest challenge in selective removal of As is the presence of phosphate in water which is chemically comparable with As(V). There are two types of mechanisms involved with As removal: Coulombic or ion exchange; and Lewis acid-base interaction. Solution pH is one of the major controlling factors limiting removal efficiency since most of the above-mentioned methods depend on complexation through electrostatic effects. The different features of two different As species make the selective removal process more difficult, especially under natural conditions. Most of the selective As removal methods involve hydrated Fe(III) oxides through Lewis acid-base interaction. Microbiological methods have been studied recently for selective removal of As, and although there have been only a small number of studies, the method shows remarkable results and indicates positive prospects for the future

Opportunities of adopting renewable energy for the nursery industry in Australia

In Australia, the nursery and garden industry provides significant economic, cultural, social and environmental benefits to the community (NGIA, 2014). The production nurseries support a diverse array of industries and end users, including retail outlets, landscapers, cut-flower growers, orchardists, vegetable growers, interiorscapers, sustainable forestry and revegetation enterprises. Overall, the gross value of production (GVP) of the broad 'nursery, flower and turf' industry in Australia is A$1271 million, which is 17% of the total GVP of Australian horticultural industry (ABS, 2013). Amenity horticulture is currently one of the fastest growing industries in Australia (NGIA, 2009). Energy use efficiency has also become increasingly important due to the increasing cost and scarcity of energy sources and also the associated greenhouse gas (GHG) emissions causing global warming (Bundschuh and Chen, 2014; Chen and Baillie, 2009a). The horticultural sector contributes about 6% of the total agriculturalGHGemissions in Australia (Deuter, 2008). Nursery operators are thus under increasing pressure to reduce their energy and carbon footprint. By improving energy efficiency and using clean energy sources, the nursery industry can drive down their carbon footprint (Abeliotis et al., 2015; Beccaro et al., 2014; Lazzerini et al., 2014; Russo et al., 2008), and also simultaneously increase their bottom line

Leaf Species-Dependent Fungicide Effects on the Function and Abundance of Associated Microbial Communities

Microbially-mediated leaf litter decomposition is a critical ecosystem function in running waters within forested areas, which can be affected by fungicides. However, fungicide effects on leaf litter decomposition have been investigated almost exclusively with black alder leaves, a leaf species with traits favourable to consumers (i.e., low recalcitrance and high nutrient content). At the same time, little is known about fungicide effects on microbial colonisation and decomposition of other leaf species with less favourable traits. In this 21 day lasting study, we explore the effects of increasing fungicide sum concentrations (0-3000 mu g/L) on microbial colonisation and decomposition of three leaf species (black alder, Norway maple and European beech) differing in terms of recalcitrance and nutrient content. Leaf litter decomposition rate, leaf-associated fungal biomass and bacterial density were quantified to observe potential effects at the functional level. Beech, as the species with the least favourable leaf traits, showed a substantially lower decomposition rate (50%) in absence of fungicides than alder and maple. In the presence of high fungicide concentrations (300-3000 mu g/L), beech showed a concentration-related decrease not only in microbial leaf litter decomposition but also fungal biomass. This suggests that favourable traits of leaf litter (as for alder and maple) enable leaf-associated microorganisms to acquire leaf-bound energy more easily to withstand potential effects induced by fungicide exposure. Our results indicate the need to deepen our understanding on how leaf species' traits interact with the impact of chemical stressors on the leaf decomposition activity of microbial communities

A review of strategies for RO brine minimization in inland desalination plants

Water scarcity in many inland areas is increasing the demand for new groundwater desalination plants. Co-produced coal seam gas (CSG) water (or coal bed methane as known in the USA), which is mostly brackish, is extracted in huge quantities during CSG production and requires advanced treatment. Reverse osmosis (RO) is the leading technology applied in municipal desalination and for treating CSG water in Australia and in some locations in the USA. Antiscalants are often dosed during RO pretreatment to prevent membrane scaling. Recovery rates are limited by antiscalant efficacy and large volumes of brine are frequently disposed of in evaporation ponds. The search for environmentally friendly methods for RO brine minimization is considered as a key global issue. In this paper, differences between inland and seawater desalination are highlighted. The existing technologies for RO brine minimization and zero liquid discharge (ZLD) for inland desalination are reviewed. The efficacy and application of two scaling reduction technologies for RO brine minimization: (i) acid/antiscalant addition and (ii) ‘high pH precipitation treatment’ are compared. Finally, more complex ZLD and volume reduction systems, such as the high efficiency RO (HERO™) and the SAL-PROC™, are analyzed as well