Potential Of Renewable Resources Research Articles

Green Economy – Innovation-based Development of Kazakhstan

Problem Statement: The stable growth and the shift to a green economy are two of the greatest challenges of our time. Purpose of Study: Formation of suggestions and recommendations for their implementation into the model of the National Strategy of Kazakhstan Sustainable Development Methods: Analysis of the Green economy concepts; analysis of international and State programs possibilities; country technical potential of renewable resources and energy sources assessment. Conclusions and Recommendations: The State initiatives such as transition to the Green Economy, formulation of the National Strategy for Sustainable Development, the Green Bridge Program and holding the International Specialized Exhibition EXPO – 2017 obviously will become the most significant steps towards the new ways of development for Kazakhstan.

Distributed generation by energy from waste technology: A life cycle perspective

Municipal Solid Waste in general and its organic fraction in particular is a potential renewable and non-seasonal resource. In this work, a life cycle assessment has been performed to evaluate the environmental impacts of two future scenarios using biogas produced from the organic fraction of municipal solid waste (OFMSW) to supply energy to a group of dwellings, respectively comprising distributed generation using solid oxide fuel cell (SOFC) micro-CHP systems and condensing boilers. The London Borough of Greenwich is taken as the reference case study. The system is designed to assess how much energy demand can be met and what is the best way to use the digestible waste for distributed energy purposes.The system is compared with two alternative scenarios fuelled by natural gas: a reference scenario, where the electricity is supplied by the grid and the heat is supplied from condensing boilers, and a fuel cell micro-CHP system. The results show that, although OFMSW alone can only supply between 1% and 4% of the total energy demand of the Borough, a saving of ∼130 tonnes of CO2 eq per year per dwelling equipped with micro-CHP is still achievable compared with the reference scenario. This is primarily due to the surplus electricity produced by the fuel cell when the micro-CHP unit is operated to meet the heat demand. Use of biogas to produce heat only is therefore a less desirable option compared with combined heat and power production. Further investigation is required to identify locally available feedstock other than OFMSW in order to increase the proportion of energy demand that can be met in this way.

Continuous volatile fatty acid production from waste activated sludge hydrolyzed at pH 12

This study adopted rapid alkaline treatment at pH 12 to hydrolyze 66% of total chemical oxygen demands. Then the hydrolyzed liquor was fermented in a continuous-flow stirred reactor to produce volatile fatty acids (VFAs) at 8-h hydraulic retention time and at 35°C. The maximum VFA productivity reached 365mg VFAsg−1 volatile suspended solids in a 45-d operation, with most produced VFAs being acetate and propionate, principally produced by protein degradation. The Bacteroidia, ε-proteobacteria and the Clostridia were identified to be the classes correlating with the fermentation processes. The fermented liquor was applied to denitrifying phosphorus removal process as alternative carbon source after excess phosphorus and nitrogen being recycled via struvite precipitation. Fermented liquors from alkaline hydrolysis–acid fermentation on waste activated sludge are a potential renewable resource for applications that need organic carbons.

Groundwater supply and demand from southern Africa’s crystalline basement aquifer: evidence from Malawi

Failure of borehole sources in weathered and fractured crystalline basement aquifers in Malawi in southern Africa has been linked with poor borehole design, mechanical failure and badly sited boreholes. However, recent work in Malawi indicates that demand may now exceed long-term resource potential in some places and that this is also a cause of water point failure. An 11-year climate cycle (including a wet and dry period) necessitates overdraft from groundwater storage during the dry-cycle years before episodic rainfall events in the wetter part of the cycle again recharge the aquifers. Data, particularly groundwater hydrograph data, are sparse, but sufficient to evaluate the long-term renewable groundwater potential for both fractured and weathered basement-aquifer types in each of the 15 management areas in Malawi. The groundwater potential or long-term renewable resource (recharge) is given by the sum of Darcian throughflow and dry-season depletion of storage. Estimated rural demand exceeds the renewable resource in the fractured-rock aquifer in two management units and in the weathered-rock aquifer in two other units. Although there is inherent uncertainty in the water-balance estimates, the likelihood that rural demand is exceeding long-term average recharge in some areas is cause for concern.

Assessment of the resource associated with biomethane from food waste

This paper assesses the resource of biomethane produced from food waste at a state level in the EU. The resource is dependent on the quantity of food waste available for anaerobic digestion and the specific methane yield from food waste. The specific method of undertaking biomethane potential (BMP) tests was shown to be crucial. BMP tests were carried out at different scales (5L and 0.5L) with different sources of inoculum, for both wet and dried substrate samples. The upper bound BMP results for source segregated canteen food waste gave specific methane yields of between 467 and 529L CH4 per kg volatile solids added. The higher results were associated with acclimatised inoculum and wet samples of food waste. The potential renewable resource of biomethane from food waste is shown to be equivalent to 2.8% of energy in transport in Ireland; this is significant as it surpasses the resource associated with electrifying 10% of the private car fleet in Ireland, which is currently the preferred option for renewable energy in transport in the country. However for this resource to be realised within the EU, source segregation of food waste must be effected. According to the Animal By-Products Regulations, digestate from source segregated food waste may be applied to agricultural land post anaerobic digestion. Digestate from food waste derived from a mixed waste source may not be applied to agricultural land. Thus biomethane from food waste is predicated on source segregation of food waste.

Effect of selected herbicides on growth and hydrocarbon content of Botryococcus braunii (Race B)

The algae Botryococcus braunii, one of the potential renewable resources for production of liquid hydrocarbons, was used for testing the effect of selected herbicides on algal growth and hydrocarbon content. Twenty-two herbicides representing 14 modes of action were assayed. Accelerated solvent extraction (ASE) was used to extract hydrocarbon from algae and the results showed that ASE was an efficient method for algal hydrocarbon extraction at 50°C extraction temperature, 10.3MPa of pressure and 1 static cycle using n-hexane as extraction solvent. The photosystem II inhibitor diuron was the most toxic herbicide for algal growth, but hydrocarbon content increased from 34.9 to 42.4% of dry biomass in the presence of a 0.1mg/L concentration of diuron. The photosystem I inhibitor diquat was inhibitory to growth of B. braunii, but hydrocarbon content increased to 43.3% of dry biomass when treated with 5mg/L diquat. S-metalochlor, a mitosis inhibitor, reduced both algal growth and hydrocarbon content. Hydrocarbon content decreased to 16.4, 14.0 and 5.5% of dry biomass, respectively when treated with 0.1, 1, and 5mg/L S-metalochlor. The carotenoid biosynthesis inhibitor fluridone did not affect algal growth at 0.1mg/L, but decreased hydrocarbon content from 34.9 to 13.2%. The fatty acid and lipid biosynthesis inhibitor thiobencarb had no effect on algal growth or hydrocarbon content at 0.1mg/L, but it inhibited algal growth and decreased hydrocarbon content from 34.9 to 7.8% at 1mg/L. The oxidative phosphorylation uncoupler dinoterb at 0.1mg/L reduced algal biomass by 52.8% and decreased hydrocarbon content from 34.9 to 30.0%. The use of B. braunii as a source of fuel will undoubtedly require the use of an outdoor open pond system. These results will be useful for improving algal oil production while developing management systems to control invasive algal species in outdoor open pond systems ultimately keeping the oil producing algae pure.

Enrichment of Fe‐Containing Phases and Recovery of Iron and Its Oxides by Magnetic Separation from BOF Slags

AbstractSteel slag normally contains a large amount of iron and its oxides. Therefore, it is a potential renewable resource in case of inadequate iron ore supply. To recover the metals from steel slag, two types of BOF slags were remelted at 1873 K. The liquid slags were cooled using four types of cooling conditions, namely, water granulation, splashing, air cooling, and furnace cooling, to investigate the influence of cooling rate on mineral components, especially the enrichment behavior of Fe‐containing minerals. Subsequently, wet magnetic separation was conducted to examine the relations between iron recovery ratio and cooling conditions. The results show that the slags under the four cooling conditions mainly contained dicalcium silicate, RO phase, FetO, 2CaO(Fe,Al)2O3, and calcium ferrite. However, tricalcium silicate, 12CaO·7Al2O3, M‐A spinel, and free CaO and MgO were occasionally observed. The amount of glass matrix decreased, the Fe‐containing minerals increased, and the minerals more fully crystallized when the cooling rate of the liquid slag was decreased. From granulation to furnace cooling of the slags, the iron content in the recovered concentrate and the iron recovery ratio both increased. This result is in agreement with the findings on phase transformation through SEM analysis.

Desalination Strategies for Energy Optimization and Renewable Energy Use

AbstractEnergy is often the most significant factor in determining the affordability and sustainability of reverse osmosis (RO) membrane facilities. More than 33 percent of the cost to produce water with RO technology is attributed to electrical demands. High-pressure pumps are the largest energy-consuming component of treatment. Renewable energy is being increasingly considered for desalination projects. Selecting the appropriate renewable energy resource depends on several factors, including plant size, feedwater salinity, remoteness, availability of grid electricity, and technical infrastructure, as well as the type and potential of local renewable energy resource. To help utilities meet an increasing need for desalination and water reuse facilities, authors of a recent study queried utilities around the world about their practices and energy and minimization strategies. This article summarizes that effort, as well as selected aspects of energy minimization and renewable energy.

Synthesis of rosin allyl ester and its UV-curing characteristics

Rosin has been recognized as a potential important renewable resource in the forest chemical industry. It is a complex mixture of high-molecular-weight organic acids and related materials. The acidic constituents that make up rosin are called resin acids, which include abietic acid, neoabietic acid and palustric acid. They can be used to synthesize many types of fine chemicals,1, 2, 3 and are widely used as raw materials to produce functional polymers.4, 5, 6, 7, 8 Woo-Sik Kim5 provided a method to synthesize poly(vinylbenzyl abietate) using poly(vinylbenzyl chloride) and sodium abietate as raw materials. Tae Hoon Kim6 reported the synthesis of polymethacrylate by the reaction of poly(glycidyl methacrylate) with abietic acid. In these two methodologies, the resin derivatives were not used as monomers in the polymerization. That is, these polymers were based on the polymerization of other kinds of monomers besides resin derivatives. The final product did not provide a suitable resin structure; the conversion of the reaction was relatively low.5, 6 Moreover, a large amount of solvent was used to purify the product after reaction. Recently, vinyl compounds have become well known as photosensitive monomers. Therefore, Woo-Sik Kim7 and Byoung-Woo Park8 developed methods to polymerize abietate derivatives by introducing a vinylbenzyl group into the molecular structure. However, it is difficult to remove the unreacted vinylbenzyl chloride by vacuum distillation because of its high boiling point (192 °C), which would bring thermal instability to vinylbenzyl abietate.

Preparation Development of High-Quality Solar-Grade Multi-Crystalline Silicon by Directional Solidification

Silicon solar cell is well known as one of the cleanest and most potential renewable resources. As the major photovoltaic (PV) material in PV industry, multi-crystalline silicon (mc-Si) grown by directional solidification has recently attracted increasing attention because of its low production cost, low pollution and high throughput. Deeper understanding of the physic and optic properties, and preparation methods of the materials will lead to improved device design. This paper briefly presents basic directional solidification theory of multi-crystalline silicon, and reviews recent development of solar-grade multi-crystalline silicon. The directional solidification preparation techniques of high-quality solar-grade multi-crystalline silicon are detailed introduced and summarized. Furthermore, the existing problems and further development direction of directionally solidified multi-crystalline silicon for solar cell are discussed.

Sustainable Development of Green Energy Technologies in the Republic of Sudan

AbstractSudan is an agricultural country with fertile soil and ample water resources, as well as livestock and forestry resources, and agricultural residues. Energy is one of the key factors in the development of Sudan's national economy. We present an overview of the energy situation in Sudan, with reference to its end uses and its regional distribution. We separate energy sources into two main types: conventional energy (biomass, petroleum products, and electricity) and non-conventional energy (solar power, wind energy, hydro-electric, etc.). Sudan has a relatively high abundance of sunshine and solar radiation, and has moderate biomass, hydro-electric and wind energy resources. Exploiting the available new and renewable energy sources to provide part of the local energy demand, as alternatives to conventional fossil energy, has become a major issue in Sudan's strategic planning of future energy policies. Sudan presents an important case study with respect to renewable energy, as it has a long history of meeting its energy needs by use of renewable sources; Sudan's portfolio is broad and diverse, due in part to the country's wide range of climates and landscapes. Like many African frontrunners in the utilisation of renewable energy, Sudan has a well-defined commitment to continue research, development, and implementation of new technologies. Sustainable low-carbon energy scenarios in the new century emphasize the importance of exploiting the untapped potential of renewable resources. Sudan's rural areas in particular, can benefit from this transition. The increased availability of reliable and efficient energy services will stimulate the development of new alternatives. We conclude that using renewable, environmentally friendly energy must be encouraged, promoted, implemented, and demonstrated by full-scale energy plants or collection devices, in particular for use in remote rural areas.

Low-cost solar grade silicon purification process with Al–Si system using a powder metallurgy technique

Silicon solar cell is one of the cleanest and most potential renewable resources. However, the high cost of raw material is impeding the development of silicon solar cell. In this paper, we have investigated a purification process designed for low-cost solar grade silicon with Al–Si system, using a powder metallurgy technique. It is found that by modulating the external pressure and/or protection ambient, the alloying of Al–Si powder mixture is easily accomplished at a relatively lower temperature. The mechanism of Si products purified from the Al–Si melt has been discussed based on their morphological characterizations. The impurity contents of the purified Si products can be controlled at a very low level (∼3 ppmw). Meanwhile, the yield of the purified Si products using the powder metallurgy technique is clarified to be higher than that of the conventional Al–Si purification technique without external pressure or protecting ambient. The process is quite potential of providing low-cost solar grade silicon feedstock for photovoltaic industry.

Renewable natural resources from the view of oil dependent countries: the case of Turkey

Increases in oil prices induce various economic and political impacts, such as greater attention being given to renewable substitute alternatives. From this perspective, this study provides some descriptive statistics and univariate estimations for one of the countries that cannot meet its demand for petroleum. Biofuel, one of the examples of renewable natural resources, may have a great potential as an oil substitute. The major problem behind this potential is to find some relationships between the oil substitutes and any other related variables. The results of both comovements and the univariate GARCH analysis of some factors related with biofuel acreage may shed light on the future policy planning of the potential of renewable natural resources in the case of an oil dependent country.

Butanol production by Clostridium beijerinckii ATCC 55025 from wheat bran

Wheat bran, a by-product of the wheat milling industry, consists mainly of hemicellulose, starch and protein. In this study, the hydrolysate of wheat bran pretreated with dilute sulfuric acid was used as a substrate to produce ABE (acetone, butanol and ethanol) using Clostridium beijerinckii ATCC 55025. The wheat bran hydrolysate contained 53.1 g/l total reducing sugars, including 21.3 g/l of glucose, 17.4 g/l of xylose and 10.6 g/l of arabinose. C. beijerinckii ATCC 55025 can utilize hexose and pentose simultaneously in the hydrolysate to produce ABE. After 72 h of fermentation, the total ABE in the system was 11.8 g/l, of which acetone, butanol and ethanol were 2.2, 8.8 and 0.8 g/l, respectively. The fermentation resulted in an ABE yield of 0.32 and productivity of 0.16 g l(-1) h(-1). This study suggests that wheat bran can be a potential renewable resource for ABE fermentation.

Simultaneous saccharification and fermentation of alkaline-pretreated corn stover to ethanol using a recombinant yeast strain

Bio-ethanol converted from cheap and abundant lignocellulosic materials is a potential renewable resource to replace depleting fossil fuels. Simultaneous saccharification and fermentation (SSF) of alkaline-pretreated corn stover for the production of ethanol was investigated using a recombinant yeast strain Saccharomyces cerevisiae ZU-10. Low cellobiase activity in Trichoderma reesei cellulase resulted in cellobiose accumulation. Supplementing the simultaneous saccharification and fermentation system with cellobiase greatly reduced feedback inhibition caused by cellobiose to the cellulase reaction, thereby increased the ethanol yield. 12 h of enzymatic prehydrolysis at 50 °C prior to simultaneous saccharification and fermentation was found to have a negative effect on the overall ethanol yield. Glucose and xylose produced from alkaline-pretreated corn stover could be co-fermented to ethanol effectively by S. cerevisiae ZU-10. An ethanol concentration of 27.8 g/L and the corresponding ethanol yield on carbohydrate in substrate of 0.350 g/g were achieved within 72 h at 33 °C with 80 g/L of substrate and enzyme loadings of 20 filter paper activity units (FPU)/g substrate and 10 cellobiase units (CBU)/g substrate. The results are meaningful in co-conversion of cellulose and hemicellulose fraction of lignocellulosic materials to fuel ethanol.

Abstract A5: Inhibition of tumor cell migration and angiogenesis by sulphated polysaccharides from Sargassum wightii (Greville)

Abstract A5 Seaweeds are potential renewable resources of the marine environment. They are low in fats but contain vitamins and bioactive compounds like terpenoids and sulphated polysaccharides. Sulphated polysaccharides from brown algae are found to exhibit diverse biological activities like anticoagulant, antihyperlipidemic, antiviral, antioxidant, antitumor, antimetastatic and antiangiogenic activities. In this study, the antiproliferative, antiinvasive and antiangiogenic properties of sulphated polysaccharides from brown seaweed, Sargassum wightii (Greville) against colon carcinoma cell line COLO 320DM were investigated. Crude sulphated polysaccharide was extracted from S. wightii collected from Mandapam coast, South east coast of India. The antiproliferative activity of the seaweed polysaccahrides on COLO 320DM was evaluated by MTT assay and DNA fragmentation studies. The inhibitory potential on the migration of this invasive cell line was assessed by wound healing assay. The effect of sulphated polysaccharides against angiogenesis was investigated by chorio allantoic membrane (CAM) assay in chick embryo. Sulphated polysaccharides from S. wightii exhibited moderate growth inhibitory activity against COLO 320DM at a concentration of 1mg/ml at 24 hours. DNA fragmentation studies revealed characteristic ladder formation which indicates that seaweed polysaccharides have effected the induction of apoptosis. The seaweed extract was found to inhibit the migration of the colon carcinoma cell line. The antiinvasive property increased with increasing concentrations. However, the activity was more or less similar at 24 and 48 hours. The CAM assay showed that sulphated polysaccharides from the brown seaweed exhibited promising activities against neoangiogenesis. These results clearly indicate that sulphated polysaccharides from brown algae are potential molecular leads for antimetastatic drug development. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A5.

Feasibility of production methods for succinic acid derivatives: a marriage of renewable resources and chemical technology

AbstractSuccinic acid has recently received a great deal of attention in various publications and presentations when discussing the potential of renewable resources for the production of chemical building blocks. As a starting material for a number of conversions, it leads to important derivatives for various industrial branches. In this review, many suggested/published processes are analyzed and the feasibility of the processes toward industrial use in comparison with actual production routes has been evaluated.Derivatives that have a high probability of being successfully produced from succinic acid are tetrahydrofuran, γ‐butyrolactone and butanediol, as well as various pyrrolidones. Other nitrogen‐containing succinic acid derivatives, as well as its esters and salts, have various uses and can be used for further conversions. Succinate‐based surfactants and polymers are produced in large quantities.This review also contains a short overview of chemicals that might be produced from succinic acid, but the routes are still not economically feasible at this point and are only of academic interest at the moment. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd

Lactic acid production from dining‐hall food waste by Lactobacillus plantarum using response surface methodology

AbstractBACKGROUND: Food waste generally has a high starch content and is rich in nutritional compounds, including lipids and proteins. It therefore represents a potential renewable resource. In this study, dining‐hall food waste was used as a substrate for lactic acid production, and response surface methodology was employed to optimise the fermentation conditions.RESULTS: Lactic acid biosynthesis was significantly affected by the interaction of protease and temperature. Protease, temperature and CaCO3 had significant linear effects on lactic acid production, while α‐amylase and yeast extract had insignificant effects. The optimal conditions were found to be an α‐amylase activity of 13.86 U g−1 dried food waste, a protease activity of 2.12 U g−1 dried food waste, a temperature of 29.31 °C and a CaCO3 concentration of 62.67 g L−1, which resulted in a maximum lactic acid concentration of 98.51 g L−1 (88.75% yield). An increase in inoculum size would be appropriate for accelerating the depletion of initial soluble carbohydrate to enhance the efficiency of α‐amylase in dining‐hall food waste fermentation.CONCLUSION: A suitable regression model for lactic acid production was developed based on the experimental results. Dining‐hall food waste was found to be a good substrate for lactic acid fermentation with high product yield and without nutrient supplementation. Copyright © 2008 Society of Chemical Industry

Zeolite Y as a Heterogeneous Catalyst in Biodiesel Fuel Production from Used Vegetable Oil

Complete recycling of waste edible oil has recently attracted considerable attention as a worldwide social problem. Production of a biodiesel fuel from used vegetable oil is considered an important step in reducing and recycling waste oil. This technology employs used vegetable oil as a potential renewable alternative resource to fossil diesel fuel, and the transesterification reaction is the usual process to obtain biodiesel. The objective of this work is to study the transesterification of waste oil with methanol in the presence of several Y-type zeolites with different Al2O3 content. In this study, the reaction is carried out in a continuous tubular steel reactor using zeolite Y as catalyst, being tested at atmospheric pressure within a reactor temperature range of 200–476 °C and methanol/oil molar ratio of 6. The results show an important decrease of viscosity of the product obtained until values close to biodiesel specifications.

Study on the Recovery of Phosphorus from Waste-Activated Sludge Incinerator Ash

Several batch studies that were made up of the acid extraction and the solvent extraction were performed to recover phosphorus from the waste-activated sludge (WAS) incinerator ash. In the acid extraction, the extraction efficiency of phosphorus relied on the acid type, liquid(acid)-to-solid (LacidS) ratio, and acid concentration. Phosphorus in the WAS incinerator ash was completely extracted by 1 M HCl at the LacidS ratio of 6.4:1. Subsequently, the solvent extraction was conducted to separate and concentrate phosphorus further from the acid extract. The efficiency of solvent extraction was affected mainly by the solvent type, liquid (solvent)-to-liquid (the acid extract) (Lsolv Lacid) ratio, and hydrogen ion concentration. Under the appropriate condition, 76% of phosphorus in the acid extract was extracted to 1-butanol phase, which corresponded to 80.1% as the mass fraction of phosphorus to total elements. Prior to the solvent extraction, the addition of bis (2-ethylhexyl) phosphoric acid (D2EHPA), which was available for removing aluminum from the acid extract, led to an additional increase in the term of the mass fraction of phosphorus to total elements. Overall results indicated that phosphorus in the WAS incinerator ash could be efficiently recovered and be a potential renewable resource.