Solid Waste Combustion Research Articles

Remanufacturing Construction and Demolition Waste and Incineration Ashes into Eco-blocks: Quantitative Sustainability Assessment

This study performed a sustainability evaluation of a proposed business for remanufacturing concrete materials from construction and demolition waste (CDW) and ash from the combustion of municipal solid waste (MSW) to produce eco-blocks for construction applications. Six possible industrial remanufacturing alternatives are proposed based on commercially available industrial machinery and their economic sustainability was compared by a cost and profit feasibility study. Furthermore, the technical feasibility was evaluated by considering the maturity of the selected machinery based on the relationships among the cost–productivity, power–productivity, and number of workers–productivity pairs. The proposed remanufacturing business achieves a maximum profit of 17,643 USD/day with a minimum remanufacturing cost of 30.65 USD/t for the production of 529 t of eco-blocks in an 8-h factory shift. A quantitative environmental sustainability assessment was performed using the remanufacturing cost, profit, concrete savings, energy savings, CO2 emission savings, and eco-cost savings as criteria based on demographic statistics from the literature for current and predicted CDW and MSW generation. CDW and incineration ash are widely available, so the proposed process is viable worldwide. Based on the technical, economic, and environmental sustainability results, a final sustainability index of 0.874 was calculated, which exceeds literature thresholds for a sustainable business, indicating that the proposed eco-block remanufacturing process has the potential to generate substantial profits, while positively contributing to reducing waste and energy usage by recovering valuable resources and producing value-added products. The remanufactured eco-blocks are prepared in the same way as typical concrete blocks and can be used for all of the same residential, commercial, and industrial construction and landscaping applications. The remanufactured eco-blocks have several advantages over typical concrete blocks, including a much lower manufacturing cost (∼50% lower), significant environmental and resource savings by avoiding the use of new sand and gravel resources, and improved mechanical properties.

Current Trends and Pressing Issues of Solid Waste Management in Developing Countries with Special Reference to Pakistan

In South Asia, Pakistan ranks as the second largest state and stands sixth globally in terms of population. This research critically examines the solid waste management (SWM) system in Pakistan, employing a qualitative methodology to assess its effectiveness. The study begins with a broad overview of SWM issues in developing countries, focusing on Pakistan's specific challenges such as mismanagement, lack of innovative techniques, insufficient budget, and inadequate policies. It scrutinizes the SWM practices across all provinces, identifying open dumping, burning of solid waste, and industrial waste disposal in water streams as prevalent methods. These techniques are analyzed for their adverse impacts on human health and the environment, highlighting the urgent need for a more effective SWM system. The research underscores the importance of adopting sustainable practices and integrating comprehensive frameworks to improve SWM. By examining empirical data and employing a robust analytical framework, the study aims to provide actionable insights for policymakers and stakeholders to enhance the sustainability and effectiveness of SWM in Pakistan. The ultimate goal is to foster a system that aligns with global sustainability standards, ensuring better environmental and public health outcomes.

Physicochemical properties and energy potential of combustible municipal solid waste from Lomé, Togo

ABSTRACT This study aims to fill the knowledge gap regarding the physicochemical properties of combustible municipal solid waste (CMSW) from Lomé under its wet and dry seasons. Over both seasons, waste characterisation campaigns were conducted followed by the proximate and ultimate analyses of CMSW samples composed of putrescible, miscellaneous combustible (MC), plastic, textile, and paper & cardboard fractions. In addition, the energy and oxide contents from CMSW were measured with a calorimeter and X-Ray Fluorescence analyser respectively. The results showed that putrescible had the highest weight proportion with significant differences among waste fractions over wet and dry seasons (p-value 1.90E–07 < 0.05). On average, textile and plastic achieved the highest volatile and lowest fixed carbon contents respectively, while plastic achieved the highest ash content. The highest carbon, hydrogen, and oxygen content was from textile, while the highest nitrogen-sulphur content was from plastic. The estimated energy potential was in the order of plastic (2.88 MJ/kg) > putrescible (2.73 MJ/kg) > textile (0.86 MJ/kg) > MC (0.67 MJ/kg) > paper & cardboard (0.18 MJ/kg). The content of silicon dioxide (75.88 wt%) and manganese oxide (0.02 wt%) were the highest and lowest from plastic, respectively. Therefore, CMSW showed important energy value though highly contaminated by fines.

Cement modified and copper oxide enriched ferric sludge as oxygen carrier for chemical looping combustion

This study focuses on enhancing the performance of water treatment sludge as an oxygen carrier (OC) for chemical looping combustion (CLC) of municipal solid waste (MSW) syngas. High aluminate cement was introduced to augment the OC’s mechanical strength, concurrently preventing inter-particulate agglomeration, resulting in a commendable and low agglomeration rate of 3.44% after 50 cycles. The inclusion of CuO proves to be instrumental in boosting the OC’s reactivity, mitigating the loss of active components due to the addition of cement support. Notably, FSCuO10 (Ferric sludge with 10% CuO addition) demonstrates over 92% CO efficiency throughout 50 cycles, affirming the success of the dual modification of FS. The investigation also delves into comprehending the reduction process, agglomeration pathways, and the impact of varied CuO percentages has on OC performance. Extensive characterizations were conducted to elucidate OC transformations and their consequential effects on reactivity, physical characteristics, and overall performance. A noteworthy observation includes the outward migration of iron and copper during CLC, contributing to the stabilization of reactivity. In summary, the modifications implemented on FS, yield an improved OC for CLC purposes, maintaining its novelty and cost-effectiveness. The novelty stems from the interactions between CuO and FS, leading to improved reactivity and stability, as well as the extended CLC, which demonstrates the longevity of the OCs. This research contributes to the circularity of waste-derived products by effectively repurposing water treatment sludge and improving sustainable waste management practices.

CFD Modelling and Optimization of Solid Waste Combustion in a 1 MW Fixed Bed Combustion Chamber

The global population and energy consumption grow each year. Therefore, the tendency to use biofuels instead of fossil fuels assist the global requirement. Also, enhancing of the combustion efficiency and minimizing pollutant emissions during the combustion of municipal solid waste (MSW). The present study employed a CFD model to simulate solid fuel combustion in a grate combustion chamber which was commonly used in small-capacity boilers. computational fluid dynamics technique was used to simulate complex solid fuel reactions where 1 MW boiler was supposed for wood and coal combustion. The achievements found that 10%-dried MSW was used as fuel. The results of the study were related to the average gas flow temperatures and composition in the furnace outflow section, as well as the high combustion temperatures of fossil fuels. The results for the average temperature and average chemical molecular fractions (CO, O2, CO2, H2O, and N2) generated at the exit of the combustion process were positive. Thus, it was found that the thermal efficiency of the boiler was significantly affected by the amount of air supplied to the system at a temperature of 273 K and atmospheric pressure. We observed variations in flame morphology, temperature profiles, and corresponding numerical values.

Development of an integrated online deposition and corrosion monitoring system in a full-scale solid waste CFB boiler

Solid waste incineration is a clean and sustainable approach for solid waste management. However, ash deposition and corrosion remain a critical issue due to fuel’s inherent enrichment of alkali chlorine. This study develops an integrated online deposition and corrosion monitoring system to enhance the operational safety and efficiency of solid waste incineration boilers. This system combines linear polarization resistance (LPR) for corrosion rate estimation with heat flux measurements for ash deposition analysis. It can offer a novel approach for real-time monitoring of heat exchangers’ safety during solid waste combustion. It was deployed in a full-scale circulating fluidized bed (CFB) boiler that purely combust solid wastes. Key findings demonstrate the system’s capability to deliver continuous, real-time data, crucial for the dynamic control of combustion processes and the maintenance of heat transfer surfaces. Its robust diagnostic capabilities were evident across various scenarios. Specially, initial corrosion rates sharply increase with deposition rates due to the enrichment of alkali chlorine on inner deposit layer, in which chlorine serves as a catalyst, facilitating the rapid penetration and aggravation of corrosion by other agents. As deposit further buildup, the corrosion rate steadily decreases along with surface temperature, highlighting a dynamic interaction. Moreover, measured corrosion rates can quickly response to temperature variations. Such multi-process online monitoring system provide more possibilities to investigate the inherent interaction between deposition and corrosion. Therefore, this work offers insights that could significantly influence operational strategies, maintenance protocols, and the overall reliability of waste-to-energy technologies.

Identification of organic constituents on atmospheric particulate matter in the East Asian background air of free troposphere by GC×GC-TOFMS

The presence of organic compounds on the particulate matter (PM) or aerosols can arise from the condensation of gaseous organic compounds on the existing aerosols, or from organic precursors to form secondary organic aerosols (SOA) through photochemistry. The objective of this study is to characterize organic constituents on aerosols relevant to their emission sources and the key compounds revealing the evolution of aerosols with the use of a novel analytical technique. A time-of-flight mass spectrometry (TOFMS) coupled with comprehensive two-dimensional gas chromatography (GC×GC) was developed using a flow type of modulator instead of a thermal type as a prelude to field applications without the need for cryogen. The methodology of GC×GC-TOFMS is discussed in this study in detail.Since the coarse PM (PM10-2.5) may exhibit with a relatively high OC content compared to PM2.5, the GC×GC results have been obtained by analyzing PM10 samples collected in parallel with OC/EC analysis of PM2.5 samples at the Lulin Atmospheric Background Station (LABS, 23.47°N, 120.87°E, 2862 m ASL) as the high-mountain background site in East Asia. We found that the organic analytes were in a majority in the range of 12–30 carbon numbers falling in the category of semi-volatile organic compounds (SVOCs) with 43 compounds of alcohol, aldehyde, ketone, and ester varieties if excluding alkanes. Intriguingly, trace amounts of plasticizers and phosphorus flame retardants such as phthalates (PAEs) and triphenyl phosphate (TPP) were also found, likely originating from regions involved in open burning of household solid waste in Southeast Asia or e-waste recycling in southern China and along the long-range transport route. Compounds such as these are unique to the specific sources, demonstrating the wide spread of these hazardous compounds in the environment.

Comprehensive source identification of heavy metals in atmospheric particulate matter in a megacity: A case study of Hangzhou

Megacities face significant pollution challenges, particularly the elevated levels of heavy metals (HMs) in particulate matter (PM). Despite the advent of interdisciplinary and advanced methods for HM source analysis, integrating and applying these approaches to identify HM sources in PM remains a hurdle. This study employs a year-long daily sampling dataset for PM1 and PM1-10 to examine the patterns of HM concentrations under hazy, clean, and rainy conditions in Hangzhou City, aiming to pinpoint the primary sources of HMs in PM. Contrary to other HMs that remained within acceptable limits, the annual average concentrations of Cd and Ni were found to be 20.6 ± 13.6 and 46.9 ± 34.8 ng/m³, respectively, surpassing the World Health Organization's limits by 4.1 and 1.9 times. Remarkably, Cd levels decreased on hazy days, whereas Ni levels were observed to rise on rainy days. Using principal component analysis (PCA), enrichment factor (EF), and backward trajectory analysis, Fe, Mn, Cu, and Zn were determined to be primarily derived from traffic emissions, and there was an interaction between remote migration and local emissions in haze weather. Isotope analysis reveals that Pb concentrations in the Hangzhou region were primarily influenced by emissions from unleaded gasoline, coal combustion, and municipal solid waste incineration, with additional impact from long-range transport; it also highlights nuanced differences between PM1 and PM1-10. Pb isotope and PCA analyses indicate that Ni primarily stemmed from waste incineration emissions. This explanation accounts for the observed higher Ni concentrations on rainy days. Backward trajectory cluster analysis revealed that southern airflows were the primary source of high Cd concentrations on clean days in Hangzhou City. This study employs a multifaceted approach and cross-validation to successfully delineate the sources of HMs in Hangzhou's PM. It offers a methodology for the precise and reliable analysis of complex HM sources in megacity PM.

Air quality and attributable mortality among city dwellers in Kampala, Uganda: results from 4 years of continuous PM2.5 concentration monitoring using BAM 1022 reference instrument.

Air pollution is a known risk factor for non-communicable diseases that causes substantial premature death globally. Rapid urban growth, burning of biomass and solid waste, unpaved sections of the road network, rising numbers of vehicles, some with highly polluting engines, contribute to the poor air quality in Kampala. To provide evidence-based estimates of air pollution attributable mortality in Kampala city, with focus on ambient fine particulate matter (PM2.5). We utilized a time series design and prospectively collected data on daily ambient PM2.5 concentration levels in micrograms per cubic meter (μg/m3) using a Beta Attenuation Monitor (BAM-1022) in Kampala city, Uganda. We combined the PM2.5 data with all-cause mortality data obtained from the Uganda Bureau of Statistics and the Ministry of Health in Kampala. We calculated attributable risk estimates for mortality using the WHO AirQ+ tools. Overall, the annual average concentration for PM2.5 for the period of 4 years, 2018-2021, was 39 μg/m3. There was seasonal variation, with the rainy season months (March-June and October-December) having lower values. PM2.5 concentrations tend to be highest in the morning (09.00 h) and in the evening (21.00 h.) likely due to increased vehicular emissions as well as the influence of weather patterns (atmospheric temperature, relative humidity and wind). Saturday has the most pollution (daily average over 4 years of 41.2 μg/m3). Regarding attributable risk, we found that of all the deaths in Kampala, 2777 (19.3%), 2136 (17.9%), 1281 (17.9%) and 1063 (19.8%) were attributable to long-term exposure to air pollution (i.e., exposure to PM2.5 concentrations above the WHO annual guideline of 5 μg/m3) from 2018 to 2021, respectively. For the 4 years and considering the WHO annual guideline as the reference, there were 7257 air pollution-related deaths in Kampala city. Our study is the first to estimate air pollution attributable deaths in Kampala city considering the target as the WHO annual guideline value for PM2.5 of 5 μg/m3. Our monitoring data show that fine particulate matter air pollution in Kampala is above the WHO Air Quality Guideline value, likely resulting in substantial adverse health effects and premature death. While further monitoring is necessary, there is a clear need for control measures to improve air quality in Kampala city.

Generation and persistency of combustion-derived environmentally persistent free radicals from phenolic compounds over a Fe2O3/SiO2 surface

Combustion of organic solid wastes releases phenolic compounds which can act as precursors in the formation of environmentally persistent free radicals (EPFRs) in the post-flame, cooling zone of waste combustion. The study investigated the generation mechanism of EPFRs from phenolic compounds catalyzed by transition metals in air atmosphere under simulated combustion conditions. Representative combustion-derived phenolic compounds were used, and SiO2 particulates containing different mass ratio of Fe2O3 were synthesized as carriers. EPFRs formed had g-factors between 1.9998 and 2.0066, indicating phenoxyl-, cyclopentadienyl-, and semiquinone-type radicals, along with paramagnetic F-centers. The promotion effect of phenolic compounds on EPFR formation during heating decreased as catechol > hydroquinone > phenol > p-cresol. This trend is related to hydroxyl groups and activation energy. In particular, catechol chemically adsorbed on Fe2O3 at 600 K led to the formation of EPFRs with relatively high spin concentrations (up to 1.28 × 1017 spin/g). Higher Fe2O3 concentrations promoted the transformation of phenoxyl-type radicals into cyclopentadienyl-type and paramagnetic F-centers. However, as the Fe2O3 loading increased from 1.25% to 5%, the density of EPFRs decreased. The findings related to the influence of various precursors and Fe2O3 concentration on EPFR formation provide valuable insights for estimating EPFR generation and associated risk during combustion processes.

Bioengineering solutions for expansive soil stabilization using waste materials: An experimental evaluation

Municipal solid waste incineration ash is the outcome/product of bioengineering science. The incineration or burning of municipal solid waste (MSW) reduces the volume of this biomass by 90%, and the residual ash can be used in several applications. In this study, the potential of municipal solid waste incineration (MSWI) ash and calcium carbide residue (CCR) waste for stabilization of expansive soil has been experimentally evaluated. The abnormal shrink–swell characteristics of expansive soils pose several problems for civil engineering structures when these soils are used for construction in their original form. The study presents an experimental set-up to determine the best combination of additives to achieve the most favorable technical characteristics of expansive soil for civil engineering activities. The percentage of expansive soil has been kept fixed at 60% of the total weight of the mix for varying ratios of stabilizing agents. The optimization of the stabilizing materials is based on the highest strength parameters of the mix achieved for a particular ratio of additives and soil. The two stabilizing agents are waste materials, and their disposal through landfilling has become costly due to a scarcity of space and handling mechanisms. The values of strength parameters, unconfined compressive strength (UCS), and split tensile strength (STS) of a treated mix are found to be highest for a unique combination of 60% lime stabilized expansive soil and 20% MSWI ash and an equal quantity (20%) of CCR. The cumulative effect of adding the best mix of additives to soil and curing time depicts an improvement of 526.03% in UCS and 463.41% in STS of the mix compared to one day and 28 days of curing time. There is scope for further study, such as adding some fibers to the finalized mix to reinforce the soil mix.

High-temperature corrosion-resistant alloy for waste-to-energy plants: Alloy designing, fabrication, and possible corrosion-resistance mechanism

This study designed a novel high-temperature corrosion-resistant alloy through thermodynamic equilibrium computations. The strength was determined by the integration of precipitation-strengthening species of nickel boride and tungsten solid solution strengthening, while high-temperature corrosion-resistant property was realized through optimized compositional design. Phase stability was enabled by the presence of a face-centered cubic structure. The alloy was fabricated and its corrosion-resistance performance was experimentally compared with other commercially available nickel- and iron-based alloys under simulated municipal solid waste combustion. The designed alloy with a composition of Ni-5B-6W-28Cr-13Al showed a low corrosion rate of ∼72 % < 13CrMo4-5TS and 1.08 % > Inconel 625. Economic analysis showed that Ni-5B-6W-28Cr-13Al has a cost-effectiveness ratio of 1:1.57 with respect to Inconel 625 and 1:0.09 with respect to 13CrMo4-5TS. Corrosion-resistance mechanism was explored using scanning electron microscopy coupled with energy dispersive spectroscopy, x-ray diffractometer, and DFT computations. The corrosion resistance occurred through the formation of a uniform tungsten-chromium-oxide film which inhibits inward diffusion of corrosive chlorine species. These findings provide insights into the development of alloys for high-temperature technologies.

Towards a low-emission resource circulation of valuable metals from municipal solid waste incineration fly ash

The incineration fly ash (IFA) resulting from municipal solid waste combustion is laden with heavy metals, necessitating proper treatment not only for environmental management but also to reclaim the metal values. The surge in non-traditional metals like cobalt as emerging contaminant within IFA samples further attracts to address this issue. In response, the hydrometallurgical recycling of a cobalt-bearing IFA has been studied. Thereby, approximately 98 % zinc and 96 % cobalt were leached using a 1.0 mol/L H2SO4 solution at 90 °C and 1 h of leaching time. In-depth analysis of the leaching process unveiled metals' dissolution primarily via the ion-exclusion mechanism, as evidenced by lower diffusion coefficients (between 10−9 and 10−11 m2/s) and activation energies (9.6–14.9 kJ/mol). Above 99 % separation of zinc from the cobalt-bearing leach liquor was achieved by extraction with 1.0 mol/L D2EHPA at an equilibrium pH below 3.0, followed by stripping with a 2.0 mol/L H2SO4 solution. Cobalt, remained in the raffinate was efficiently precipitated by adding a 20 % excess dosage of oxalic acid to the stoichiometric ratio of C2O42−:Co2+, resulting in only 5 mg/L cobalt left in the solution when precipitation occurred at a pH of 2.8. Additionally, the conversion of CoC2O4 to high-purity Co3O4 was conducted through heat-treatment at 600 °C. The resulting Co3O4 was mixed with Li2CO3 at a Li/Co molar ratio of 1.1, yielding a LiCoO2 precursor that exhibited good electrochemical properties with a capacity of 128 mAh/g, thus affirming the high quality of the recycled cobalt. A comprehensive life-cycle assessment of the recycling process revealed that cobalt precipitation alone contributes approximately 50 % of the total global warming potential (GWP = 4.2624 kg CO2-eq). Notably, this value is remarkably lower than the GWP reported for primary cobalt production, highlighting the environmentally-friendly approach of this recycling endeavor.

Statement on Impact of Air Pollution on Human Health; Africa Region

The impacts of air pollution on human health are enormous and in African region, morbidity and mortality from air pollution causes rose since 1990. The significant sources of air pollution have been observed from human activities such as Industrialization, agricultural burning, transport and traffic, combustion of wood, coal, paraffin and animal dung for household energy needs, dusty roads and burning of household solid waste in areas without regular residential waste collection services. Africa with a poor health system faces a severe lack of air pollution detection metrics, with only 7 out of 54 countries having air quality detection monitors. Long- and short-term exposure to air pollution is associated with increasing rate of morbidity and mortality from acute and chronic respiratory diseases, cardiovascular diseases and cancers. The progression of asthma, lung cancer, cardiovascular diseases, Alzheimer's and Parkinson's diseases is linked to air pollution exposure. Measures to reduce and control air pollution in Africa Region have been suggested in this paper.

Environmental impacts analysis of Moroccan olive cake combustion in Stirling motor cogeneration system: Case study

Morocco is the world's 5th largest olive oil producer with 160,000 tons in 2020/2021 and the production of 1 L of olive oil generated approximately 5 kilos of waste olive cake, this type of waste is dangerous for the environment and especially for groundwater. To address this issue and take into account the thermal properties of olive waste, our project's goal is to produce power and heat by using solid olive waste in a Stirling cogeneration system. Therefore, the goal of this article is to examine by using CFD tools the environmental impacts of the Moroccan solid olive waste burning in a CHP (combined heat and power) unit. The idea is to integrate a smart renewable energy system based on olive cake and the Stirling motor to produce electricity in order to employ this electrical energy for water pumping in rural areas.The impact of the excessive air ratio on temperature profile and exhaust has been investigated and discussed. In addition, the pollutant species in air has been presented, and compared with guideline values given by some international organization for health and environment. Results show that the highest excess air ratio gives high temperatures with a homogeneous distribution around the Stirling motor hot heat exchanger, and minimum emissions of CO, CO2, NO, NO2 and NH3 that do not exceed the values set by WHO, OSHA, and NIOSH.

Study on the distribution, enrichment and migration characteristics of trace elements in particulate matter during solid waste combustion

Trace element emissions caused by the entrainment of particulate matter (PM) has led to serious environmental pollution. This research focuses on the distribution, enrichment and migration characteristics of trace elements in different sizes of PM during the typical solid waste combustion. The results indicate that the mass concentration of trace elements in different PM is closely related to their volatility. Volatile trace elements such as Cu, In, Ag, Pb, and Cd tend to distribute in PM1. Higher temperatures facilitate the volatilization of trace elements, promoting their migration and enrichment in finer PM. The removal effect of Si–Al-based additives on trace elements in PM1 decreases with the increase of Si/Al ratio. Among them, the removal efficiency of 5% kaolin is the best. After the addition of Si–Al-additives, Zn and In mainly migrate to PM1-10, while Cu, V, Mo, As, Se, Cr, Ba, Mn, Co, Sr, and Ti mainly migrate to PM10+. Ag, Pb, and Cd migrate to both PM1-10 and PM10+ simultaneously.

A long-term perspective on coal combustion solid waste interacting with urban soil

Diverse wastes are produced during coal combustion and part of it is recycled worldwide in construction, agriculture, and other industries. As the waste becomes part of the environment, both intentionally and unintentionally, it is important to understand its long-term impact on surrounding soils. In this study, we characterized the situation where such waste, composed of mixed slag, fly ash, gangue, and coke material, was deposited 10–15 years ago as a layer within the urban soil. Two types of soil profiles were identified characterized by a different emplacement of the waste, which either occurred as a 10-cm thick layer or thin seams. Combined chemical and mineralogical analyses of the buried waste showed that slag fragments were affected by the dissolution of primary phases and precipitation of secondary carbonates, Fe-(hydr)oxides, and silica. The impact of the waste was detected in the underlying soils using ratios of trace elements enriched in the waste versus the uppermost soils (e.g., Ni/Pb, V/Zn, Ba/Pb) showing that it might be possible to recognize areas affected by similar deposited waste products. Combined leaching and mineralogical observations showed that V was released, but most probably as particles of unreactive V-rich sulfides, and Ba was preferentially leached from Ba-rich slag glass. Moreover, a combination of mineralogical observations, trace element ratios, and Pb isotopes showed that the thick layer of the waste may have acted not only as a source of potentially toxic elements but also as a trap (insulator) that stopped contamination coming from other sources (e.g., atmosphere).

Extraction of tracer elements of particulate matter emission source using association rule mining

The source marker species represent the emission source in the ambient air. It aids in identifying specific emission sources, but it can deliver ambiguous results when similar species exhibit different emission sources. Therefore, robust marker/tracer species are always needed to clearly identify emission source. This study collected tracer elemental species for possible emission sources from Indian published literature and processed them by using machine learning-based apriori algorithm to obtain robust elemental marker of the emission source. Initially, significant rules were chosen with support >10% and lift >1.0. Subsequently, elemental markers have obtained by applying constraint i.e. conviction ≥1.1, lift ≥1.4 and confidence ≥20%. As an outcome, it reveals elemental markers of crustal emission (CE) (Al, Si, Fe, Ca, Mg, Ti), sea salt (SS) (Na, K), biomass burning (BB) (K), solid waste burning (SWB) (Ba, Cd, Cr, Sr), coal combustion (CC) (As, Se, Cr, Cd), oil combustion (OC) (V, Ni, S, As), and traffic emission (TE) (Cu, Pb, Zn, Mn, Cd, Ni). Finally, robust elemental markers corresponding to their respective emission source were derived by applying constraint of conviction ≥1.1, lift ≥1.5 and confidence ≥50% on the previously extracted association rule. Consequently, it defined CE by Mg, Al, Ca, Si, Fe, SS by Na, K, TE by Cu, Pb, Mn, Zn, SWB by Ba, Cr, Cd, Sr, OC by V, Ni, S, and CC by Se, As. Additionally, this study also demonstrate the successful implementation of the apriori algorithm for the aforementioned task.

Combustion of Date Stone and Jojoba Solid Waste in a Hybrid Rocket-like Combustion Chamber

The performance of two solid biomass wastes, date stone and jojoba solid waste, was experimentally examined for their potential application in combustion and propulsion systems. The fuels were tested in a hybrid rocket-like combustion environment, and the test result was analyzed with combustion and propulsion parameters. The performance of both fuels was comparatively evaluated and compared with a conventional hydrocarbon fuel in a hybrid rocket, with paraffin wax serving as a baseline. A compression device was introduced to compress the solid biomass wastes into a circular-shaped fuel grain compatible with a hybrid rocket combustion chamber with a hot surface ignitor. Thermogravimetric analysis (TGA) and chemical equilibrium analysis (CEA) results revealed that the performance of the biomass fuel can be comparable to conventionally used hydrocarbon paraffin-wax-based propellant within a certain range of oxidizer-to-fuel ratio, in terms of theoretical specific impulse performance. Through experimental performance tests, it was found that the compressed biomass fuel grains were successfully ignited and produced thrust. Both biomass fuels tested in a hybrid rocket combustion chamber are expected to pave the way for further developments in biomass fuels in the waste-to-energy field for their application in combustion and propulsion systems, potentially replacing fossil fuels with renewable resources.

Assessment of the contribution of residential waste burning to ambient PM10 concentrations in Hungary and Romania

Abstract. The illegal burning of solid waste in residential stoves is an existing practice, but until now it has been completely disregarded as an emission source of atmospheric pollutants in many developed countries, including those in eastern Europe. Various types of solid waste (plastics, treated wood, plyboards, tyre, rag) serve as an auxiliary fuel in many households, in particular during the heating season. In this work, for the first time ever in atmospheric pollution studies, specific tracer compounds identified previously in controlled test burnings of different waste types in the laboratory were detected and quantified in ambient PM10 samples collected in five Hungarian and four Romanian settlements. Using the identified tracers and their experimentally determined relative emission factors, the potential contribution of illegal waste burning emissions to ambient PM10 mass concentrations was assessed. Our findings implied that the burning of polyethylene terephthalate (PET)-containing waste (food and beverage packaging, clothes) was predominant at all the locations, especially in north-eastern Hungary and Romania. There is substantial evidence that the burning of scrap furniture is also common in big cities in Hungary and Romania. Back-of-the-envelope calculations based on the relative emission factors of individual tracers suggested that the contribution of solid waste burning particulate emissions to ambient PM10 mass concentrations may be as high as a few percent. This finding, when considering the extreme health hazards associated with particulate emissions from waste burning, is a matter of serious public health concern.