Low-grade Waste Research Articles

Low transfer of cadmium, lead and aflatoxin B1 to eggs and meat of laying hens receiving diets with black soldier fly larvae reared on contaminated substrates

Replacing soybeans with insects in egg and poultry meat production could improve environmental sustainability. Black soldier fly larvae (BSFL) have a favorable nutrient composition and can be reared on low-grade waste, but this is associated with the risk of feed and food contamination. The aim of this study was to assess the transfer of selected contaminants from larval substrates to poultry-derived food. Two different control substrates were used. Substrate CCH (produced in Switzerland) was based on side streams approved for insect rearing in the European Union (EU), while substrate CIND (produced in Indonesia) included non-EU approved waste. In addition, substrate CIND was spiked with either heavy metals (HM; 1.9 mg cadmium and 18.8 mg lead/kg dry matter (DM)) or 1.5 mg aflatoxin B1/kg DM (AF)). The larvae fed HM contained 7 mg cadmium and 16 mg lead/kg DM. These values were about 30 times the concentrations of cadmium and 30–60 times the concentrations of lead found on average in the BSFL reared with the two non-spiked substrates. Although substrate AF contained 842 μg aflatoxin B1/kg DM as analysed, the AF larvae contained only 4 μg aflatoxin B1/kg DM. Larval meals were integrated at 200 g/kg in two control diets (diets CCH and CIND) and two diets based on contaminated BSFL (diets HM and AF) designed for late-laying hens (n = 9/treatment). After feeding these diets for 4 weeks, the hens were slaughtered. Diet HM and AF did not affect laying performance or egg quality compared with the control diets. In the body tissue, the cadmium concentrations (per kg DM) were nearly doubled by diet HM in the breast meat (13.3 μg), kidneys (12.3 mg) and liver (1.86 mg) compared to diet CIND. The same diet increased lead in kidneys from below 0.1 to 0.5 mg/kg DM. No lead was detected in the meat and eggs, and no cadmium was found in the eggs. In conclusion, despite cadmium and lead also occurring in BSFL meals of CCH and CIND, the levels in all corresponding hen-based feed and food materials were below the maximum content, except for the kidneys. The aflatoxin B1 level of diet AF (1 μg/kg DM) suggests that the risk might also be small when BSFL are reared on moldy substrate containing aflatoxin-producing fungi. In conclusion, postconsumer waste apparently poses a lower risk than expected in poultry food chains for these contaminants when used as larval substrate.

Carbon dioxide sequestration and wastewater treatment via an innovative self-sustaining algal microbial fuel cell

In this research, the utilization of an algal assisted-microbial fuel cell (AMFC) that employed photosynthetic microorganisms as cathode catalysts was demonstrated for the treatment of synthetic wastewater (SWW), power generation, and carbon sequestration. The power and biomass generation of two photosynthetic microorganisms, namely Chlorella sorokiniana and Tetradesmus sp., were evaluated. The electrogenic activity of Citrobacter frundii present in the SWW was analyzed using cyclic and linear sweep voltammetry. The AMFC exhibited a higher power density of 47.57 ± 0.95 mW/m3 with Chlorella sorokiniana in comparison to Tetradesmus sp. (46.56 ± 0.95 mW/m3). Additionally, the effect of CO2 supply on AMFC performance was investigated. The simultaneous treatment and energy recovery from low-grade waste such as SWW was found to be feasible with COD removal efficiency of 74 ± 0.6% in both AMFCs. Furthermore, the elementary analysis of lyophilized biomass of Chlorella sorokiniana and Tetradesmus sp in SWW-B showed maximum carbon content of 49.3% and 49.1%, respectively. The maximum biomass concentration and carbon fixation rate were determined to be 2.8 ± 0.03 g L−1 d−1 and 1.4 ± 0.001 g L−1 d−1, respectively for Chlorella sorokiniana. Additionally, the series of experimental results show that the stacked AMFCs had the capability to light the 3.0 V LED bulb. These findings suggest that AMFCs have the potential for sustainable bioelectricity generation and wastewater treatment with added benefits of carbon sequestration and biomass production.

Experimental Assessment of the Performance and Emissions of a Spark-Ignition Engine Using Waste-Derived Biofuels as Additives

The use of biofuels for spark ignition engines is proposed to diversify fuel sources and reduce fossil fuel consumption, optimize engine performance, and reduce pollutant emissions. Additionally, when these biofuels are produced from low-grade wastes, they constitute valorisation pathways for these otherwise unprofitable wastes. In this study, ethanol and pyrolysis biogasoline made from low-grade wastes were evaluated as additives for commercial gasoline (RON95, RON98) in tests performed in a spark ignition engine. Binary fuel mixtures of ethanol + gasoline or biogasoline + gasoline with biofuel incorporation of 2% (w/w) to 10% (w/w) were evaluated and compared with ternary fuel mixtures of ethanol + biogasoline + gasoline with biofuel incorporation rates from 1% (w/w) to 5% (w/w). The fuel mix performance was assessed by determination of torque and power, fuel consumption and efficiency, and emissions (HC, CO, and NOx). An electronic control unit (ECU) was used to regulate the air–fuel ratio/lambda and the ignition advance for maximum brake torque (MBT), wide-open throttle (WOT)), and two torque loads for different engine speeds representative of typical driving. The additive incorporation up to 10% often improved efficiency and lowered emissions such as CO and HC relative to both straight gasolines, but NOx increased with the addition of a blend.

Optimal Use of Industrial Hemp for PLA Biocomposite and LLDPE Composite Reinforcement

This study investigated the optimal use of industrial hemp fibers for polylactide (PLA) biocomposite and linear low density polyethylene (LLDPE) composite reinforcement. In these samples both low-grade fiber, waste and high-quality hemp fiber are used. To optimize the use of hemp fiber in both the biocomposite and the fossil-based polymer matrix composite, the first phase of the technology envisages the use of high-quality hemp fibers in the production of the PLA biocomposite. This process also produces a by-product (hemp waste). Further, in the second stage, the technology envisages the use of hemp waste in the production of LLDPE (semi-fossil) composite. PLA and hemp fiber biocomposites have high mechanical properties, which allow reducing the amount of materials in the product. Also, low-grade fiber composites show remarkable mechanical properties. The advantage of extracting hemp fibers is that it is possible to use all parts of the plant at the same time for the production of different products – hemp seeds, their shells, hemp shives, thus maximizing the value added of this resource, that conforms to the concept of sustainable development and circular economy principles. Also, it improves the ecological assessment (Life Cycle Assessment) of the product and reduces the environmental impact. Annually renewable hemp fiber resource has the potential to create new products and develop the renewable material industry in EU. Considering the Europe Green Deal guidelines [1], it is important for the manufacturer to provide a sustainable, economically justified and environmentally friendly material (switch to recyclable materials till 2021, switch to recycled, reusable or alternative materials till 2025).

Recovery of manganese from a low-grade waste and valorization via the synthesis of a nanostructured magnetic manganese ferrite

This study aims at recovering manganese from a low-grade mining waste and valorizing it through the synthesis of manganese ferrite (MnFe2O4). Full recovery of manganese from the low-grade waste was obtained by heat treatment (700 °C), and leaching optimization of the waste in a reductively promoted sulfuric acid medium. Subsequently, the Fe: Mn molar ratio (2:1) of the leachate was adjusted to prepare the precursors for the MnFe2O4 synthesis through co-precipitation. The optimization of the synthesis parameters including temperature (15–90 °C), aging time (0–120 min), and calcination temperature (800–1200 °C) was investigated. The optimum condition suggested by the response surface method (RSM) led to the synthesis of pure plate-like MnFe2O4. Additionally, nano-sized particles (45 nm) were obtained at the 90 °C synthesis temperature, 120 min aging time, and without any calcination. Both nano-sized and plate-like MnFe2O4 particles with the saturation magnetization of 34.47 and 51.03 emu g−1 presented superior magnetic properties.

A PRACTICAL APPROACH FOR TEACHING THE ORGANIC RANKINE CYCLES (ORC) IN AN ADVANCED THERMODYNAMICS COURSE

Higher Education Institutions must consider the most recently developed technologies to increase energy efficiency. A significant share of the heat used in industry is wasted while still being at usable temperature levels and hence a significant energy saving potential is present in this sector. The Organic Rankine Cycle (ORC) is a system that uses low-grade waste or renewable heat to produce electricity and lower grade heat and can be integrated into a variety of applications. In this paper, an introduction to ORCs is presented, and then, a practical example of a laboratory session using an experimental test bench based in this technology in a last year bachelor’s degree course is detailed. A commercial ORC machine was run in the laboratory session, where the students were able to explore its operation through the graphical interface. They applied the main thermodynamic concepts in the interpretation of the behavior and seen the utility of this science in recently developed environmentally friendly technologies. Then, the students simulated a real case based on the valorisation of exhaust gases from an engine installed in a wastewater treatment plant. Students agreed that the combination of both parts in this session is beneficial for their understanding and that ORC machines are a viable solution to control climate change. Keywords:Combined Heat and Power (CHP); Higher Education (HE); applied thermodynamics; laboratory session; experimental setup; real problem solving

Development and Testing of Novel Applications for Adsorption Heat Pumps and Chillers

This work aims at the development and the experimental characterization of new applications for adsorption heat pumps and chillers driven by industrial waste heat or renewable sources that can provide heating and/or cooling. Adsorption technologies offer the advantage of providing heating and cooling from low temperature sources below 100 °C without using refrigerant with high Global Warming Potential and with very low electricity consumption. Therefore, the technology enables the use of large untapped heat sources, increasing the energy efficiency of the heating and cooling sector with very limited impact on the environment. Several applications were investigated numerically for Switzerland using a simplified model of an adsorption heat pump. Four scenarios were identified as interesting: (1) the valorization of low-grade industrial waste heat in district heating networks, (2) energy efficiency improvement of district heating substations, (3) an autonomous adsorption heat pump with a wood pellets burner and (4) cooling applications. These scenarios were experimentally validated with a laboratory test of a commercial silica gel/water machine. Results show that there is a gap of up to 40% between the prediction of the simplified model and the experimental results. Therefore, there is huge potential to improve the performances of this commercial unit for these applications.

Bioleaching for resource recovery from low-grade wastes like fly and bottom ashes from municipal incinerators: A SWOT analysis.

Bioleaching (or microbial leaching) is a biohydrometallurgical technology that can be applied for metal recovery from anthropogenic waste streams. In particular, fly ashes and bottom ashes of municipal solid waste incineration (MSWI) can be used as a target material for biomining. Globally, approximately 46 million tonnes of MSWI ashes are produced annually. Currently landfilled or used as aggregate, these contain large amounts of marketable metals, equivalent to low-grade ores. There is opportunity to recover critical materials as the circular economy demands, using mesophile, moderately thermophile, and extremophile microorganisms for bioleaching. A Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis was developed to assess the potential of this biotechnology to recover critical metals from MSWI wastes. Bioleaching has potential as a sustainable technology for resource recovery and enhanced waste management. However, stakeholders can only reap the full benefits of bioleaching by addressing both the technical engineering challenges and regulatory requirements needed to realise and integrated approach to resource use.

Classification of Low-Grade Copper-Nickel Ore and Mining Waste by Ecological Hazard and Hydrometallurgical Processability

Classification of Low-Grade Copper-Nickel Ore and Mining Waste by Ecological Hazard and Hydrometallurgical Processability

Sustainable regional development in the context of bioeconomic trend: Pskov Region

The article presents arguments for the strategy of regional sustainable development (on the example of Pskov region), based on the implementation of the forest potential of the territory on the principles of bioeconomy with a cluster approach to the organization of regional space. The expansion of the biofuel market is a key external factor for the production of pellets made from low-grade wood and forest waste in countries and regions with an appropriate natural, economic and geographical potential. The parameters of the objective trend - transition of Russian regions to bioeconomy, which will allow them not only to increase regional incomes by expanding opportunities for public-private partnership, but also to improve their own competitiveness in the national economy, are outlined. In addition, due to cluster approach, the prerequisites for the formation of regional space network structure are obvious. Methods of logical and substantive, strategic, statistical, regional, technical and economic analysis, as well as content analysis and SWOT analysis are applied in the study.

Efficiency of biomass and solid waste energy processing based on the cogeneration plant with plasma heat source

The urgency of the use of low-grade organic fuels and wastes, in particular municipal solid (MSW), is due to recent developments in energy saving and energy efficiency. This directly relates to the direction of renewable energy, responsible for involving all wastes, such as MSW, in fuel energy balance to provide heat and electricity to decentralized power supply areas. This paper presents the process of high-temperature thermal decomposition of MSW in the steam-air medium of plasma under excessive pressure to generate electrical energy. The high enthalpy and great reactivity of the plasma gasifying agent makes it possible to carry out the process of thermal decomposition in the autothermal mode. The high-temperature mode and the use of plasma blast provides a high degree of conversion of waste into combustible components (CO, CH4, H2), the resulting gas mixture. The technological process significantly reduces the formation of potentially hazardous substances that affect the kinetics of the process. After generating electrical energy, the exhaust gases are subjected to complex purification from the products of combustion and cogeneration of residual thermal energy. In particular, purification from toxic nitrogen oxides (NOx) occurs, the formation of dioxins, furans and other dangerous derivatives of chloride compounds is prevented. Thermal energy, discharged at various sites of the plant, is almost completely used for the needs of the cogeneration plant and its units, which allows to achieve a total efficiency of at least 86%. The ability of the cogeneration plant to work on various types of solid waste gives a wide range of applications and operational capabilities.

Концептуальные подходы к формированию лесопромышленных кластеров в России

World experience shows the effectiveness of the creation of clusters in various industries. A lot of work and research domestic and foreign scholars and practitioners are dedicated to study and development of mechanisms of realization of industrial policy. The article analyzes the main indicators of the forest industry and forestry in Tomsk region in recent years, the basic provisions are revealed, Factors determining the development trends of the industry are analyzed. The authors identified the major systemic problems hindering the progressive development of forest sector in Tomsk region, including low level of development of periodic yield, the lack of transport and economically available forest resources, inadequate production structure and export of forest products, financial situation of enterprises of the sector, insufficient staffing, weak territorial cooperation of the enterprises and organizations. The article defines the objective conditions for creation of timber industry cluster in Tomsk region, goals, objectives and directions of sustainable development of the forest sector in Tomsk region on the basis of cluster approach are identified. Among the main areas that determine competitiveness of products and possibility of increasing the efficiency of forest management, the following issues are highlighted: development of deep processing of wood through the use of low-grade wood and wood waste, development of transport infrastructure in forests, improving human potential, expanding the range of manufactured timber enterprises in the cluster of products and implementation of joint projects. The conclusions can provide theoretical basis for further research in the field of economic security and development of timber processing complex and forestry. Obtained results can be used both by researchers in further research work to explore issues of cluster development of timber industry and regional authorities and business structures functioning in the sphere of forest industry.

Effect of mass recovery evaporator temperature and condenser temperature on the performance of a solar adsorption-based desalination plant

ABSTRACTWater scarcity increases alarmingly as the population increases. Over the years, a number of salt water desalination techniques have been proposed and reached limitations. The requirement of minimum energy is very well satisfied by an adsorption system, since it can operate with low-grade energy and waste heat exhaust from most industries. The first part of this work discusses the effect of condenser and evaporator temperatures on the performance of silica-gel adsorption cycle mathematically. The second part discusses the performance variations due to mass recovery in the two-bed adsorption system mathematically. It was found that the reduction in condenser temperature and increase in the evaporator temperature both increase the fresh water productivity and cooling capacity of a plant. A desalination plant with mass recovery assistance is superior in performance than the conventional plant. Portable water productivity of 8 m3/day/ton is achieved with the condenser temperature of 15°C and the evaporator temperature of 30°C.

Experience in vegetable waste burning in furnace block TBR-2.0

There are various types of furnace systems with use of alternative and local fuels with the fluidized bed for grain drying. A low-quality fuel burns in the fluidized bed better, than in dense one. As well emissions of nitrogen oxides decrease very much. Ecological, operational and economic benefits of these fire chambers are certain. They are especially perspective for combustion of low-grade fuels and various waste (for example, waste of agricultural production) in a ciclonic and vortex layer. The distinctive feature of such fire chambers is availability of vortex contours in the burning camera that increases efficiency of burning process. The authors carried out testing of the furnace block with grain dryer SZT-30 at OOO «Borisoglebsky MEZ» (Voronezh region) at corn and sunflower seeds drying. We burned sunflower peelings with the lowest calorific power of 14 MJ and 17 MJ at 1 furnace block capacity of 100, 210, 230, 250, 280, 320 and 380 kg per hour. The set of two furnace blocks (TBR-2.0) operating with sunflower peelings which are characterized by the lowest calorific power at least 17 MJ per 1 kg will provide necessary capacity of the dryer SZT-30 when grain and seeds drying. The maximum capacity of the unary thermal block TBR-2.0 should not exceed 1.5 MW. As well the maximum efficiency is reached, and extent of air heating provides functioning of the dryer at a temperature of external air not below 5 degrees Celsius. The economy and safe mode of operation of the furnace block can be provided in case of capacity 0.8-1.3 MW and 1.2-1.5 times air-fuel ratio. In this case emissions of nitrogen oxides are less than permitted value and equal 0.6-0.7 g per 1 cubic meter.

Characterization of solid product obtained via chemical degradation process of low grade lignite and waste tyre

Characterization of solid product obtained via chemical degradation process of low grade lignite and waste tyre

Boron Waste Concentration Using Shaking Table

The most important Iranian boron reserves are in the basin of GHEZEL-OUZAN, a river in the West and Northwest area of Zanjan. The majority of these mines have been extracted with a non-advanced way. There are many great waste damps next to the mines which are a threat to the environment for releasing boric acid and because of an average grade of Boron are valuable from financial point as well. Present paper studies possibility of concentration a low-grade boron waste from Moshampa boron mine using shaking table. In order to concentration, 6 factors in 5 levels were considered. The factors included: particle size, water flow rate, frequency, liberation range, tilt angle and feed rate. Optimization was carried out by classic method (one factor at the time). As a result, optimum condition obtained under particle size of +1.18 -2 mm, water flow rate of 3.5 lit/min, frequency of 320 cycle/min, liberation range of 15 mm, tilt angle of 8 degrees and feed rate of 250 g/min. This test yielded 58.43% of B2O3 recovery under optimum conditions performance, and a concentrate with 26.45% B2O3 was produced.

Potential of composite fuel application based on low-grade coal and wastes of forest and flour industry

Composite fuels based on low-grade brown coal of 3B-grade mixed with forest and flour industry wastes were studied. Three compositions with similar weight content of forest industry waste and low-grade coal as well as flour industry waste in concentration range from 0 to 15 wt. %. The chemical properties and ignition characteristics of samples were studied by means of TG-analysis at air medium and 10 K/min heating rate in temperature range 50-600 °C. The samples with 15 wt. % content of flour waste were found to have higher burnout degree (up to 21.17 %) and mechanical endurance while having lower heating value (up to 6 %) and higher ignition temperatures (up to 24 °C) compared to samples with no flour industry wastes.

Gasification of Low-Grade Coal and Coal Wastes in the Mode of Filtration Combustion

Gasification of Low-Grade Coal and Coal Wastes in the Mode of Filtration Combustion

有机朗肯循环在工业低品味余热回收中的应用

有机朗肯循环在工业低品味余热回收中的应用

Modelling of organic Rankine cycle system and heat exchanger components

Numerical models of a standard organic Rankine cycle (ORC) system and the heat exchangers comprising the system are developed as a design tool platform for a flexible design. The objective is design of an efficient, cost-effective ORC power plant that can effectively exploit low-grade industrial waste heat or low to medium-temperature geothermal fluid. Typical heat exchanger configurations were modelled, including the circular finned-tube evaporator, air-cooled condenser, and flat-plate preheater. A published ORC configuration and process conditions from experiments are used for the thermodynamic cycle analysis in order to validate of the system model. Heat transfer correlations and friction factors are described for the modelling of the heat exchangers. The simulation results of the ORC system provide the design requirements for the heat exchangers. Geometric specifications and performance of the heat exchangers are determined by iterative simulations.