Waste Energy Recovery Research Articles

Evaluation of Incinerator Performance and Policy Framework for Effective Waste Management and Energy Recovery: A Case Study of South Korea

Waste incineration is a crucial component of waste management as it is the final stage of circular utilization and the initial phase of disposal. Effective waste management prioritizes energy recovery from waste and substantial waste volume reduction while committing to minimizing air pollutant emissions, particularly nitrogen oxides (NOx). This study involves an in-depth analysis of operational data from 44 incineration facilities in South Korea spanning 5 years, supplemented by empirical measurements from 14 sites. This study aimed to assess three key aspects of these incineration facilities: (1) waste volume reduction characteristics, (2) energy recovery capabilities, and (3) NOx emission reduction performance. We examined how these elements interact within the policy framework governing incinerator management in South Korea. Quantitatively, incinerating 100 tons of municipal waste resulted in a gain of 338.7 m3 in landfill capacity and recovery of 637.5 GJ of energy in the form of heat or electricity. Notably, South Korean incineration facilities significantly extend the lifespan of landfill sites, aligning closely with the objectives of the South Korean Ministry of Environment’s “No More Direct Landfilling of Household Waste Policy”. This positive outcome is further reinforced by the “Incineration Tax Reduction Policy”, which incentivizes active efforts toward energy recovery during incineration. Our study provides decision-makers with valuable insights for achieving a harmonious equilibrium between environmental sustainability and resource utilization, thereby contributing to the continuous improvement of policies aimed at South Korea’s vision of achieving a circular economy.

Equilibrium Modelling and Optimization of the Co-gasification of E-waste and Petcoke

Addressing the critical issues of Electronic waste (E-waste) with its low recycling and environmental impacts, this study highlights the necessity for efficient waste management and energy recovery. Leveraging petroleum coke's rich carbon content, co-gasification presents a viable method to transform E-waste into syngas. Using response surface methodology (RSM), the research analyzes various E-waste and petroleum coke blends, focusing on how gasification temperatures and pressures affect cold gas efficiency (CGE). Results highlight that the 25% printed circuit board (PCB) socket blend achieves an optimal CGE of 66.03% at 1,171.27°C and 1.95 bar via RSM and attains 64.10% CGE at 1,150°C and 1 bar as per the equilibrium model, in contrast to the 75% blend's CGE of 49.96% at 1,256°C and 1.57 bar, and 47% at 1,250°C and 1 bar. These findings reveal significant optimization opportunities in co-gasification processes, providing key insights for efficient E-waste handling and syngas generation.

Production of Composite Briquette Fuel from Brewery Wastewater Sludge and Spent Grains.

Biomass waste energy recovery is a significant method for recycling energy from waste and capturing it for use in renewable energy sources. The abundance of brewing byproducts, such as brewery spent grain (BSG) and brewery wastewater sludge (BWWS), as well as their high carbon concentrations gives these wastes energy potential. With 20% molasses utilized as a binding agent to maximize the high caloric value of the briquette, this study sought to examine the quality of mixed briquettes made from BSG and BWWS. In order to make composite briquettes with a maximum caloric content of 19.94 MJ/kg, the ideal conditions were chosen, which included a temperature of 350°C, a production period of 60 min, and a 75% BSG mixing ratio. It can be compared to sawdust briquettes, which have a calorific value of 22.88 MJ/kg, by looking at the calorific value of densified with pressure 100 bar for mixed carbonized briquettes vs mixed noncarbonized briquettes (21.13 MJ/kg). The value of R 2 was 0.9607 and indicated that 96.07% of the total validation in the calorific value correlation between experimental and predicted values. The finding of the study showed that the efficiency of the quadratic model in fitting the data would be higher under the conditions of the experiment. Based on ISO 17225-6 fuel quality classes and specifications for graded nonwoody pellets, the study concluded that using BSG and BWWS as alternative energy sources meets those requirements.

Enhanced biomethane production from waste activated sludge anaerobic digestion by ceramsite and amended Fe2O3 ceramsite

Wastes recycling and reutilization technique could simultaneously fulfill waste control and energy recovery sustainably, which has attracted increasing attention. This work proposed a novel waste reuse technology utilizing ceramsite and amended Fe2O3-ceramsite made from waste activated sludge (WAS) as additives to promote the yield of methane from WAS anaerobic digestion (AD). Experimental results demonstrated that compared to the control (85.05 ± 0.2 mL CH4/g-VS), the cumulative methane yield was effectively enhanced by 14% and 40% when ceramsite and Fe2O3-ceramsite were added. Further investigation revealed that ceramsite, especially the Fe2O3-ceramsite, enriched the populations of key anaerobes involved in hydrolysis, acidification, and methanogenesis. Meanwhile, potential syntrophic metabolisms between syntrophic bacteria and methanogens were confirmed in the Fe2O3-ceramsite AD system. Mechanisms studies exhibited that ceramsite and Fe2O3-ceramsite reinforced intermediate processes for methane production. The favorable pore structure, enhanced Fe (III) reduction capacity and conductivity also contributed a lot to the AD process.

Impact of Implementing Circular Waste Management System and Energy Recovery in a City with 100,000 Inhabitants on Nitrogen Emissions by 2035

Recent years have observed a reconstruction of the waste management system from a linear resource flow economy to a circular economy. This approach is reflected in the provisions of the Waste Framework Directive (2018), which introduces, among others, new recycling targets for municipal waste which require, by 2025, 55% of the municipal waste to be recycled, in 2030—60%, and in 2035—65%. The ambitious targets adopted for preparing for the reuse and recycling of municipal waste will not be achieved without a high level of the recycling of bio-waste. This paper studies the quantification of municipal waste and nitrogen in a circular municipal waste management system (MWM) implemented for a city of 100,000. It was assumed that MWM would meet the requirements in terms of EU and Polish circular waste management goal legislation for the years 2025, 2030 and 2035. The research results showed that the development of a separate waste collection will reduce the waste delivered to MBT. The required MBT capacity will decrease by almost 2.4 times. Moreover, it has been shown that the introduction of a closed-loop MWM will result in an almost two-fold reduction in the amount of nitrogen going to the landfill and an increase in the mass of nitrogen that can be used to fertilize the soil (by approximately 22%). Furthermore, it has been shown that the most favorable option for an organic waste treatment is the anaerobic–aerobic process. This solution provides the highest biogas production and the lowest nitrogen gas emissions to air.

Performance Analysis and Multi-Objective Optimization of a Cooling-Power-Desalination Combined Cycle for Shipboard Diesel Exhaust Heat Recovery

This study presents a novel cooling-power-desalination combined cycle for recovering shipboard diesel exhaust heat, integrating a freezing desalination sub-cycle to regulate the ship’s cooling-load fluctuations. The combined cycle employs ammonia–water as the working fluid and efficiently utilizes excess cooling capacity to pretreat reverse osmosis desalination. By adjusting the mass flow rate of the working fluid in both the air conditioning refrigeration cycle and the freezing desalination sub-cycle, the combined cycle can dynamically meet the cooling-load demand under different working conditions and navigation areas. To analyze the cycle’s performance, a mathematical model is established for energy and exergy analysis, and key parameters including net output work, comprehensive efficiency, and heat exchanger area are optimized using the MOPSO algorithm. The results indicate that the system achieves optimal performance when the generator temperature reaches 249.95 °C, the sea water temperature is 22.29 °C, and 42% ammonia–water is used as the working fluid. Additionally, an economic analysis of frozen seawater desalination as RO seawater desalination pretreatment reveals a substantial cost reduction of 22.69%, showcasing the advantageous features of this proposed cycle. The research in this paper is helpful for waste energy recovery and sustainable development.

Assessing the feasibility of recovering heat from Mung Bean sprout production for food consumption

Given the current challenges posed by climate change and depletion of conventional fuel resources, there is a need to focus on improving energy efficiency through the recovery of waste energy. One such potential source of low-temperature waste heat is the process of seed germination during food plant cultivation. In traditional production facilities, germinating plants generate low-temperature heat (20–40 °C), which is typically discharged into the environment. This paper presents a study on the heat recovery potential of germinating Mung bean seeds under laboratory and controlled cultivation conditions using an isothermal calorimeter and a process line, respectively. This study represents the first quantitative determination of the heat generated during the Mung bean sprout production cycle, and a comparison of the changes in emitted heat on both micro and macro scales. Additionally, the research includes the first determination of the amount of energy generated by Mung bean sprouts using microcalorimetric studies lasting up as long as 120 h. The paper determines the amount of heat generated and estimates the possible and actual heat recovery potential. The results show that the average amount of heat generated in the calorimetric studies is 2.43±0.72 kJ/gseeds, while under controlled cultivation conditions it is 2.29 kJ/gseed. These findings highlight the significant potential for recovering waste heat from germinating seeds, which can be harnessed to improve the energy efficiency of the food sprout production process. In addition, the calorimetric method is suitable for determining the energy potential of plants and facilitating the design of the most efficient crop cultivation techniques in terms of energy consumption.

Waste Management in the Smart City: Current Practices and Future Directions

The discourse surrounding sustainability, particularly in the urban environment, has gained considerable momentum in recent years. The concept of a smart city epitomises the integration of innovative technological solutions with community-centred approaches, thereby laying the groundwork for a sustainable lifestyle. One of the crucial components of this integration is the effective and innovative management of waste. The aim of this article was to classify scientific research pertaining to waste management within the context of smart city issues, and to identify emerging directions for future research. A systematic literature review, based on a bibliometric analysis of articles included in the Scopus and Web of Science databases, was conducted for this study. The purpose of such a systematic review is to identify, integrate, and evaluate research on a selected topic, using clearly defined criteria. The research query included: TITLE-ABS-KEY (“smart city” AND (waste OR garbage OR trash OR rubbish)) in the case of Scopus, and TS = (“smart city” AND (waste OR garbage OR trash OR rubbish)) in the case of the Web of Science database. A total of 1768 publication records qualified for the analysis. This study presents an investigation into the current and forthcoming directions of waste management in smart cities, synthesising the latest advancements and methods. The findings outline specific future research directions encompassing technological advancement, special waste challenges, digitisation, energy recovery, transportation, community engagement, policy development, security, novel frameworks, economic and environmental impact assessment, and global implications. These insights reflect a multifaceted approach, advocating a technology-driven perspective that is integral to urban sustainability and quality of life. The study’s findings provide practical avenues for cities to enhance waste management through modern technologies, promoting efficient systems and contributing to sustainable urban living and the circular economy. The insights are vital for policymakers and industry leaders globally, supporting the creation of universal standards and policies, thereby fostering comprehensive waste management systems aligned with global sustainability objectives.

Analysis of heavy metal, rare, precious, and metallic element content in bottom ash from municipal solid waste incineration in Tehran based on particle size

Waste incineration is increasingly used worldwide for better municipal solid waste management and energy recovery. However, residues resulting from waste incineration, such as Bottom Ash (BA) and Fly Ash (FA), can pose environmental and human health risks due to their physicochemical properties if not managed appropriately. On the other hand, with proper utilization, these residues can be turned into valuable Municipal metal mines. In this study, BA was granulated in various size ranges (< 0.075 mm, 0.075–0.125 mm, 0.125–0.5 mm, 0.5–1 mm, 1–2 mm, 2–4 mm, 4–16 mm, and > 16 mm). The physicochemical properties, heavy metal elements, environmental hazards, and other rare and precious metal elements in each Granulated Bottom Ash (GBA) group from Tehran's waste incineration were examined using ICP-MASS. Additionally, each GBA group's mineralogical properties and elemental composition were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD). The results showed that the average concentration of heavy metals in GBA, including Zn (1974 mg/kg), Cu, and Ba (790 mg/kg), Pb (145 mg/kg), Cr (106 mg/kg), Ni (25 mg/kg), Sn (24 mg/kg), V (25 mg/kg), As (11 mg/kg), and Sb (29 mg/kg), was higher in particles smaller than 4 mm. Precious metals such as gold (average 0.3 mg/kg) and silver (average 11 mg/kg) were significantly higher in GBA particles smaller than 0.5 mm, making their extraction economically feasible. Moreover, rare metals such as Ce, Nd, La, and Y were detected in GBA, with average concentrations of 24, 8, 11, and 7 mg/kg, respectively. The results of this study indicated that BA contains environmentally concerning metals, as well as rare and precious metals, with high concentrations, especially in particles smaller than 4 mm. This highlights the need for proper pre-treatment before using these materials in civil and municipal applications or even landfilling.

Techno-Economic Comparison of Dual-fuel Marine Engine Waste Energy Recovery Systems

Techno-Economic Comparison of Dual-fuel Marine Engine Waste Energy Recovery Systems

Comprehensive Review of Liquid Air Energy Storage (LAES) Technologies

In recent years, liquid air energy storage (LAES) has gained prominence as an alternative to existing large-scale electrical energy storage solutions such as compressed air (CAES) and pumped hydro energy storage (PHES), especially in the context of medium-to-long-term storage. LAES offers a high volumetric energy density, surpassing the geographical constraints that hinder current mature energy storage technologies. The basic principle of LAES involves liquefying and storing air to be utilized later for electricity generation. Although the liquefaction of air has been studied for many years, the concept of using LAES “cryogenics” as an energy storage method was initially proposed in 1977 and has recently gained renewed attention. With the growing need for alternative energy storage methods, researchers have increasingly explored the potential of cryogenic media, leading to the development of the first LAES pilot plant and a growing body of research on LAES systems. However, one notable drawback of LAES is its relatively low round-trip efficiency, estimated to be around 50–60% for large-scale systems. However, due to its thermo-mechanical nature, LAES offers versatility and can be easily integrated with other thermal energy systems or energy sources across a wide range of applications. Most of the existing literature on LAES focuses on thermodynamic and economic analyses, examining various LAES configurations, and there is a clear lack of experimental studies in this field. This paper aims to conduct a comprehensive review of LAES technology, with a focus on the performance enhancement of these systems. Future perspectives indicate that hybrid LAES solutions, incorporating efficient waste energy recovery sections, hold the most promise for enhancing the tech-no-economic performance of standalone LAES systems.

Multidisiplinary design optimization of a power generation system based on waste energy recovery from an internal combustion engine using organic Rankine cycle and thermoelectric generator

The research paper mainly deals with waste heat recovery from internal combustion engines (ICE) using the organic Rankine cycle (ORC) and Thermoelectric generator (TEG). Simultaneously recovering the wasted heat of both exhaust gases and coolant, a novel configuration named two-stage is proposed. Then a comprehensive thermo-economic analysis and optimization are conducted. Produced power and total cost rate are selected as the objective function of the optimization. Also, the first and second stage pressures of the ORC system are considered as decision variables. Finally, a sensitivity analysis is performed to study the effect of expander inlet temperature, pumps isentropic efficiency, and expander isentropic efficiency on the objective function.

Comparison of exergy and exergy economic evaluation of different geothermal cogeneration systems for optimal waste energy recovery

Since energy sources are limited, any activity aimed at recycling energy waste or facilitating energy conversion systems is invaluable. Against this background, most scientists focus on the integration of energy systems and the coupling of different technologies. In this study, a variety of power systems are investigated for optimal power conversion configurations of geothermal sources. Three configurations, Organic Rankine Cycle Geothermal Cooling (GPR/ORC), Kalina Cycle Geothermal Cooling (GPR/Kalina), and Rankine Cycle and Feed water Heater (GPR/FWH) Geothermal Cooling, are classified according to exergy and Study energy economic analysis. Calculations show that the GPR/FWH system has the highest net output power of 2963 kW. In addition, the GPR/Kalina system has the lowest output power and lowest energy efficiency among the systems launched. Across the three proposed systems, the fuel cell generates 1254 kW of electricity, while the Kalina cycle in the GPR/Kalina system generates 487 kW. Exergy studies show that the GPR/Kalina and GPR/FWH systems have the lowest and highest irreversibility (3795.4 kW and 4365.56 kW, respectively). Furthermore, the fuel cell was found to have the greatest exergy destruction rate among the three configurations. The results of the economic analysis show that the fuel cell has the highest cost ratio among all designs. In addition, the values of the dissipation factor show that the absorption chiller has the highest dissipation factor value among the three configurations. Furthermore, the comparative parametric analysis provides new aspects to introduce into the system.

Small-scale Waste Heat Recovery through incineration – a brief review

This paper brings a brief discussion about small-scale waste to energy units, specifically using incineration. Solid waste treatment is an important issue around the world. Incineration has been applied successfully in developed countries. In the south hemisphere landfills and dumps are still predominant. This study aims to show that there is a lack of small-scale waste-to-energy (WtE) incineration plants and one of the reasons is associated with the high cost of the installations. The review performed showed that Organic Rankine Cycle (ORC) has been applied in smallscale plants as a tentative to reduce costs related to infrastructure required for electrical energy production. The air pollution control process also has a huge impact on this kind of installation. The lack of data and information about the operation of these plants turn difficult the study. Public policies to encourage small-scale waste energy recovery are required to improve these techniques, especially in developing countries.

Thermally Derived Hierarchical Nanoplates for Electromagnetic Protection and Waste Energy Recovery Device.

With the advent of intelligent society and the popularity of electronic equipment, the protection and treatment of electromagnetic (EM) radiation have become hot research topics all over the world. Herein, novel 2D carbon-based nanoplates with uniformly embedded Co nanoparticles are prepared, with unique hierarchical structure and integrated magnetic-dielectric components. The obtained hierarchical nanoplates exhibit a wide range of tunable EM properties (ε' for 3.38 to 34.67 and ε″ for 0.13 to 31.45) by manipulating the dispersed states inside wax system, which can achieve an effective switch from microwave absorption to EM interference shielding performance. The optimal reflection loss reaches -55.6dB, and the shielding efficiency is 93.5%. Meanwhile, the hierarchical nanoplates also exhibit impressive capacitive performance, with a specific capacitance of 1654 Fg-1 at 1 Ag-1 . Based on this, a creative device is constructed with the nanoplates, which can convert harmful EM radiation to useful electric energy for recycling. This work offers a new idea for the development of EM materials and functional devices, powerfully promoting the advance of energy and environmental fields.

Bibliometric analysis on the applicability of anaerobic digestion in organic solid waste

Anaerobic biological treatment can comprise a viable route of CH4 production through the energy recovery of organic solid waste (OSW). This work therefore presented a bibliometric analysis of research trends on the theme "Applicability of biological treatment via Anaerobic Digestion in Organic Solid Waste", considering experimental articles published from 2018 to 2022 in the Web of Science database™; the analysis used VoSviewer software to define research trends, and found that the main terms addressed in the mapped scientific articles were anaerobic, waste, sludge, waste food, municipal waste, anaerobic co-digestion, sewage sludge, organic fraction, co-digestion and biogas. As a product of such mapping, an Interaction Network Diagram was constructed comprising the main terms in addition to a theoretical foundation on anaerobic digestion and biochemical and microbiological aspects about the process.&#x0D; Keywords: anaerobic co-digestion, clean energy, food waste, microbial intercropping.

Impact of sandwich-type composite anodic membrane on membrane fouling and methane recovery from sewage sludge and food waste via electrochemical anaerobic membrane bioreactor

Membrane fouling presents a big challenge for the real-world implementation of anaerobic membrane bioreactors (AnMBRs) in digesting high-solid biowastes. In this study, an electrochemical anaerobic membrane bioreactor (EC-AnMBR) with a novel sandwich-type composite anodic membrane was designed and constructed for controlling membrane fouling whilst improving the energy recovery. The results showed that EC-AnMBR produced a higher methane yield of 358.5 ± 74.8 mL/d, rising by 12.8% compared to the AnMBR without applied voltage. Integration of composite anodic membrane induced a stable membrane flux and low transmembrane pressure through forming an anodic biofilm while total coliforms removal reached 97.9%. The microbial community analysis further provided compelling evidence that EC-AnMBR enriched the relative abundance of hydrolyzing (Chryseobacterium 2.6%) bacteria and methane-producing (Methanobacterium 32.8%) archaea. These findings offered new insights into anti-biofouling performance and provided significant implications for municipal organic waste treatment and energy recovery in the new EC-AnMBR.

4E analysis and optimization of a biomass-fired waste-to-energy plant integrated with a compressed air energy storage system for the multi-generation purpose

A novel multi-generation system is introduced based on the combination of biomass gasifier-fired steam Rankine cycle (SRC) and compressed air energy storage (CAES) system. The output power of SRC feeds the compressor and electric heater of the CAES system. A domestic hot water heat exchanger and an absorption chiller are used to waste heat utilization of gasifier-SRC and a trilateral cycle (TLC) is utilized to waste energy recovery of the CAES system. Then, the output power of TLC is sent to a proton exchange membrane electrolyzer for the production of hydrogen. Hence, the considered system is converted to a power, heating, cooling, and hydrogen multi-generation system. Energy, exergy, exergy-economic and environmental studies are done on the layout in a base case, parametric analysis, and design optimization. The three-objective optimization results in the exergy round trip efficiency (ERTE), total cost rate, and unit cost of multi-generation of 41.205%, 708.136 $/h, and 17.206 $/GJ. The improvement of ERTE (30.23%) is the most visible one in comparison to the base case outputs.

Heat Transfer in Thermoelectric Generators for Waste Energy Recovery in Piston Engines

This paper investigates the design of a thermoelectric generator for exhaust gases from internal combustion engines. Experimentally validated CFD methodology was employed. Different issues are studied, such as the influence of the replacement of the exhaust pipe for the TEG, the recirculation produced, and the influence of fins. The results show that an enlarged inlet cone reduces the recirculation and the pressure drop of the TEG, but more heat is lost across the cone walls, reducing the heat available for the thermoelectric modules. Internal straight fins aligned with the flow achieved a 3% increase in heat transfer, did not significantly increase the pressure drop in this type of device, and reduced the effects on pressure of the recirculation, lowering the overall pressure drop by 10%. An energy production of 175.9 W with 16.2 W of pressure drop power losses resulted in a net energy production of 160.7 W. A comparison with a flat-type thermoelectric generator under the same hot source conditions is also provided.

Revealing the mechanism of novel nitrogen-doped biochar supported magnetite (NBM) enhancing anaerobic digestion of waste-activated sludge by sludge characteristics

Anaerobic digestion (AD) is a promising technology in waste treatment and energy recovery. However, it suffers from long retention time and low biogas yield. In this study, novel nitrogen-doped biochar supported magnetite (NBM) was synthesized and applied to enhance the AD of waste-activated sludge. Results showed that NBM increased cumulative methane production and SCOD removal efficiency by up to 1.75 times and 15% respectively at 5 g/L compared with the blank. NBM enhanced both hydrolysis and methanogenesis process during AD and the activities of α-glucosidase, protease, coenzyme F420 and electron transport system were increased by 19%, 163%, 104% and 160% respectively at 5 g/L NBM compared with the blank. NBM also facilitated the secretion of conductive protein in extracellular polymeric substances as well as the formation of conductive pili, leading to 3.18–7.59 times higher sludge electrical conductivity. Microbial community analysis revealed that bacteria Clostridia and archaea Methanosarcina and Methanosaeta were enriched by the addition of NBM, and direct interspecies electron transfer might be promoted between them. This study provides a practical reference for future material synthesis and its application.