Waste Combustion Research Articles

Simplified mathematical model of oxy-fuel combustion of municipal solid waste in the grate furnace: effect of different flue gas recirculation rates and comparison with conventional mode

Bioenergy carbon capture technology (BioCCS or BECCS) plays a key role in the European Green Deal, which aims to decarbonize industry and energy sectors, resulting in the production of energy with negative CO2 emissions. Due to the biogenic origin of carbon contained in municipal solid waste (MSW), the application of carbon capture in waste incinera-tion plants can be classified as BioCCS. Thus, this technology has attracted scientists' attention recently since it reduces excessive waste and emissions of carbon dioxide. Currently, there are four incineration plants in the Netherlands, Norway and Japan, in which CO2 capture is implemented; however, they are based on the post-combustion technique since it is the most mature method and not requires many changes in the system. Nevertheless, the separation of CO2 from the flue gas flow, which contains mostly nitrogen, is complex and causes a large drop in the total performance of the system. Oxy-fuel combustion technology involves the replacement of air as an oxidizer into high purity oxygen and recirculated exhaust gas. As a result, CO2-rich gas is produced that is practically ready for capture. The main goal of the study is to develop a math-ematical model of oxy-waste combustion to answer the research questions, such as how the composition of oxidant that is supplied to the process affects the combustion performance. The model includes all important processes taking place within the chamber, such as pyrolysis, char burnout and gas combustion over the grate. The results of the work will contribute to the development of oxy-waste incineration plants and will be useful for design purposes.

Experimentation of Grate Combustion of Municipal Solid Waste in Ouagadougou: Influence of Primary and Secondary Air Flow on Thermal Potential

The present work concerns the study of the influence of combustion air flows on the thermal potential during the combustion of a 2 kg mixture of solid model waste from the city of Ouagadougou. This mixture consists primarily of wood, cardboard and plastic. The prototype model is a natural laterite internal-walled grate furnace. During these investigations, we were interested in the temperature variation measured by 4 thermocouples K1 to K4 placed respectively from the waste bed to the top of the furnace. These variations are considered according to a variable primary and secondary air flow. The maximum primary and secondary airflow is 3000 L/min. Measurements are taken throughout the experiment at a step of 18 seconds and a maximum duration of 3 minutes for each case of flow considered. Maximum temperatures reaching 450oC are observed following the injection of secondary air only. This is explained by the supply of oxygen making the combustion more complete. The results show that the injection of primary and secondary air at a flow rate of 1500 L/min gives a more stable temperature result, i.e. 362,18oC 186,82oC 109,27oC 72,41oC respectively for the thermocouples K1, K2, K3, K4. An increase in the primary and secondary air flow to a maximum of 3000 L/min leads to a drop in temperatures due to the dilute internal atmosphere. These results allow to set the optimal operating parameters of the furnace in order to produce more heat for its recovery into electricity through a heat exchanger and a steam turbine.

Solid waste management in Ugandan developing cities: Material flow analysis and sustainable practices for reducing the global warming potential.

The introduction of appropriate solid waste management (SWM) strategies can foster the mitigation of waste open dumping and burning in low-income developing cities. In this work, the SWM system in Gulu (Uganda) has been studied, and a material flow analysis, also of informal flows of waste, has been carried out. Moreover, the effectiveness of the SWM system of St. Mary's Lacor Hospital in Gulu was evaluated. Waste has been characterized and a material flow analysis allowed to highlight the difference with the current situation in the remaining part of Gulu. The sustainable practices already implemented in the hospital compound were studied to be replicated in Gulu to mitigate SWM impact in terms of global warming potential. Inadequate financial resources pose a hurdle for Gulu municipality in managing municipal solid waste (MSW) effectively. The SWM system of the hospital demonstrated both financial and managerial competence, paving the way to promote waste recycling actions acting as a hub for fostering sustainable and health-conscious valourization technologies, while discouraging waste open burning and dumping. This study estimated that the total CO2-eq emissions from open dumping and open burning avoided in 2030-2050, if Gulu would appropriately dispose of MSW by 2030, are equal to about 17,000 metric tonnes per year (t year-1). This work suggests appropriate strategies to mitigate waste open burning in low-middle income countries. The results can be helpful for waste management planners and practitioners providing important information for the use of appropriate technologies in low-middle income developing cities.

Seasonal occurrence and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments and water in the left-bank canals of Indus River, Pakistan.

This study investigated a pressing environmental concern: the presence, distribution, sources, and ecological implications of sixteen polycyclic aromatic hydrocarbons (PAHs) in the left-bank canals of Kotri barrage-Akram, Pinyari, and Phuleli of the Indus River in Pakistan. These vital waterways, crucial for industrial, domestic, and agricultural activities, are experiencing contamination threats from anthropogenic sources, particularly PAHs. The study collected three water and two sediment samples from each canal in pre-monsoon and post-monsoon seasons. Then the EPA's liquid-liquid extraction method and gas chromatography determined the concentrations of PAHs. The findings of this study reveal alarming contamination levels, with pre-monsoon concentrations ranging from 22.256 to 836.455ng/L in water and 1,459.941 to 43,179.243ng/g in sediments. The post-monsoon concentrations ranged from 60.352 to 5663.058ng/L in water and 2976.770 to 15,238.335ng/g in sediments. The diagnostic ratios and principal component analysis (PCA) identified multiple sources of contamination, including industrial and domestic wastewater discharge, solid waste burning, vehicular emissions, biomass combustion, and petroleum residues. Furthermore, the assessment of the toxic equivalency factor (TEF) underscored the heightened carcinogenic potential of certain PAHs, notably benzo(a)pyrene and benzo(a)anthracene. Thus, the high levels of PAH contamination pose severe health risks to both human populations and aquatic ecosystems, emphasizing the urgency of addressing this issue. Stricter regulations governing industrial and domestic waste discharge, advocacy for cleaner fuel technologies, and the implementation of effective waste management practices must be initiated as crucial strategies in safeguarding the environmental integrity of the left-bank canals and the health of the surrounding communities.

Environmental And Health Implications of Waste Disposal Sites In The Lesotho Lowlands

Many Southern African countries, including Lesotho, face severe health and environmental issues attributed to waste disposal. The purpose of this study is to assessed the environmental and health impacts on residents living in proximity to disposal sites in the lowlands of Lesotho. A descriptive cross-sectional design was employed, using a semi-structured questionnaire and observation method. A mapping device was used, and photographs were taken to validate the findings. Descriptive statistics and the Chi-square test (?²) were employed to analyze the data. Results indicate that in Lesotho, some landfill sites are located as close as 50 meters from residential areas, and most (60%) received hazardous mixed waste streams. Waste burning and backyard dumping were the most frequently used disposal methods by residents. Several perceived health outcomes and environmental issues were noted, with respiratory and gastrointestinal health issues being the most prevalent. There was a statistically significant association between waste burning and respiratory diseases (P < 0.010) and between backyard dumping and gastrointestinal diseases (P < 0.003). The study concludes that regulatory instruments need to be revised and enforced, requiring hazardous waste producers to take responsibility for end-of-life waste and banning the entry of such waste into disposal sites. The application of waste management strategies to initiate other preferable end-of-life waste procedures, such as recycling of WEEE and waste-to-energy technologies for organic waste in Lesotho, could improve the quality of health for residents and their environment.

Performance evaluation on the chemical looping combustion of the chromium-containing leather waste and the fate of chromium using thermodynamic analysis

Leather waste (LW) consistently contains a high content of chromium (Cr), which significantly limits its utilization due to the toxicity of hexavalent chromium formed through oxidation. To prevent this oxidation, chemical looping combustion (CLC) is employed to dispose of the chromium-rich LW. First, the gaseous and solid pollutants generated during air combustion and CLC are compared when LW is used as fuel. The results indicate that CLC is an effective way to significantly decrease the oxidation of chromium (Cr(VI)/Crtotal) at typical operating temperatures. Subsequently, various operating parameters, namely the equivalence ratio of oxygen carrier to leather waste (αOC/LW), the equivalence ratio of steam to leather waste (αS/LW), and air reactor (AR) temperature, are changed to investigate their effects on the CLC combustion and pollutant behaviors. The findings reveal that no chromium is oxidized in the fuel reactor. The oxidation in AR is associated with the presence of Na in the AR, which can react with chromium to form Na2CrO4. Increasing αOC/LW from 0.8 to 1.2 reduces the oxidation of chromium in the AR from 11.68% to 1.76%, while increasing αS/LW from 0.2 to 1.6 has the opposite effect, improving the oxidation of chromium in the AR from 3.16% to 5.18%.

Bioenergy and bioexergy analyses with artificial intelligence application on combustion of recycled hardwood and softwood wastes

Novel biomass bioenergy-bioexergy analyses via thermogravimetry analysis and artificial intelligence are employed to evaluate the three biofuels from wood wastes (softwood-SW, hardwood-HW, and woods blend-WB). The chemical characterization of SW has the highest bioenergy (higher heating value – HHV: 18.84 MJ·kg-1) and bioexergy (specific chemical bioexergy – SCB: 19.65 MJ·kg-1) with the SCB/HHV ratio of wood waste as about 1.043-1.046. The high C-element has a significant influence on the HHV-SCB. The SCB/HHV ratio of wood waste is recognized as about 1.043-1.046. The three distinct zones of wood waste combustion are identified: moisture evaporation (Zone I, up to 110 °C), combustion reaction – degradation of three major lignocellulosic components (hemicelluloses, cellulose, and lignin) at Zone II, 110-600 °C, and ash remains (Zone III, 600-800 °C). The ignition (Dig=0.01-0.04) and fuel reactivity (Rfuel=3.82-6.97 %·min-1·°C-1) indexes are evaluated. The comprehensive combustion index (Sn:>5×10-7%2·min-2·°C-3) suggests that wood waste has a better combustion performance than bituminous coal. The statistical evaluation presents that the highest HHV-SCB values are obtained by performing combustion for SW-250 μm at 15 °C·min-1. The S/N ratio and ANOVA results agree that the wood waste type and particle size denote the most influential parameters. The artificial neural network prediction shows an excellent result (R2=1) with 1 hidden layer and 5 neuron configurations.

Studying and Promoting Knowledge on Sustainable Agricultural Waste Management: A Case Study in Banhan Upper Secondary School and Surrounding Schools in Hongsa District, Xayaboury Province, Lao PDR

The investigation took place at Banhan upper secondary school in the Hongsa district of Xayaboury Province. It spanned a duration of 12 months and involved providing TOT training on managing reused and recycled waste to 35 students and teachers at the school. Additionally, 48 trash bins were supplied and set up across 7 schools and 3 related offices. A school received a trash bin to collect recyclable waste that was set up for the students' practice. The findings presented that 94.71% with understanding index 1.24 SD of the students and teachers were displayed a good understanding and comprehended the project's activities, with 83.47% with sastisfacting index 0.77 SD expressing satisfaction. Only a small fraction, less than 5.29%, struggled with waste management and required further enhancement of their knowledge and skills. The waste collected from 10 locations comprising schools and offices underwent 8 rounds of 2 months collection. In total, 1,121.2 Kg of waste was disposed of, averaging 280.3 Kg per mounth. The waste output in schools increased due to the growing number of students and educators. Banhan upper secondary school accounted for the highest waste quantity output at 49.7 Kg/month (17.73%), followed by Monk lower secondary school at 36.2 Kg/month (12.91%), and Nasan primary school at 33.8 Kg/month (12.06%) and the least amount of waste was generated by the district office of Education and Sports only 13.7 Kg/month (4.89%) representively. The quantity of 4 categories of waste revealed that the burnable waste promoted largest quantity 149.9 Kg/month (4.99 Kg/day), connected by compost waste 71.4 Kg/month (2.38 Kg/day), Reusable waste 60 Kg/month (2 Kg/day) and harmful waste 2 Kg/month (0.07 Kg/day). Waste in a day per person was calculated from populalation of the institution in 8h a day (working day), result shown that district office of Natural Resource and Enviroment has a high significant in quantity of waste 0.0351 Kg (35.1 g)/person/day. Then, Phonchan primary school 0.0221 Kg (22.1 g)/person/day and Nasan primary School 0.0205 Kg (20.5g)/person/day, the lowest quantity of waste was Hongsa upper secondary school 0.0012 Kg (1.2 g)/person/day. Nevertheless, the primary emphasis of this research was on the quantities of waste can be reuse, aiming to enhance awareness among academic staff, teachers, and students. The goal is to ensure comprehension, discourage indiscriminate disposal of garbage, and promote waste reduction through practices such as reuse and recycling.

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.

Atmospheric black carbon in the metropolitan area of La Paz and El Alto, Bolivia: concentration levels and emission sources

Abstract. Black carbon (BC) is a major component of submicron particulate matter (PM), with significant health and climate impacts. Many cities in emerging countries lack comprehensive knowledge about BC emissions and exposure levels. This study investigates BC concentration levels, identifies its emission sources, and characterizes the optical properties of BC at urban background sites of the two largest high-altitude Bolivian cities: La Paz (LP) (3600 m above sea level) and El Alto (EA) (4050 m a.s.l.), where atmospheric oxygen levels and intense radiation may affect BC production. The study relies on concurrent measurements of equivalent black carbon (eBC), elemental carbon (EC), and refractory black carbon (rBC) and their comparison with analogous data collected at the nearby Chacaltaya Global Atmosphere Watch Station (5240 m a.s.l). The performance of two independent source apportionment techniques was compared: a bilinear model and a least-squares multilinear regression (MLR). Maximum eBC concentrations were observed during the local dry season (LP: eBC = 1.5 ± 1.6 µg m−3; EA: 1.9±2.0 µg m−3). While eBC concentrations are lower at the mountain station, daily transport from urban areas is evident. Average mass absorption cross sections of 6.6–8.2 m2 g−1 were found in the urban area at 637 nm. Both source apportionment methods exhibited a reasonable level of agreement in the contribution of biomass burning (BB) to absorption. The MLR method allowed the estimation of the contribution and the source-specific optical properties for multiple sources, including open waste burning.

Agricultural Waste for Energy Storage, Conversion and Agricultural Applications

Agricultural waste residues (agro-waste) present a significant source of carbohydrates that are often underutilized despite their valuable properties. With increasing urbanization and limited non-renewable resources, the valorization of agro-waste is imperative. The global energy demand is on the rise, driven by factors such as population growth, industrialization, and a desire for enhanced living standards. Traditional energy sources, especially fossil fuels, have come under scrutiny for their environmental impact and limited availability. Consequently, there is an increasing focus on developing renewable and sustainable energy solutions, particularly through the use of agricultural waste. Agricultural waste—including crop residues, animal manure, and byproducts from food processing—represents a largely untapped resource for energy production. Converting this waste into valuable energy can help meet rising energy needs while offering environmental and economic advantages, such as mitigating waste disposal issues and creating additional income sources for the agricultural sector. Despite the significant potential of agricultural waste for energy storage and conversion, several challenges remain. These include issues related to logistics and transportation, the need for pretreatment, and concerns about economic feasibility. Future research should aim to enhance conversion technologies and better integrate agricultural waste into energy and agricultural systems. This review discusses various energy conversion technologies and applications of agricultural waste, including biofuels, biogas, and direct combustion, while exploring its role in energy storage through biochar. This review examines the composition and properties of agricultural waste, the various technologies available for energy conversion, and how agricultural waste can be utilized as a feedstock for biofuels, biogas, and direct combustion. It also investigates the integration of agricultural waste in energy storage solutions like biochar and explores other agricultural applications beyond energy production.

IoT- enabled crop waste mulching machine for sustainable farming: perspective of circular economy

Abstract A large amount of crop waste is generated after crop harvesting. A substantial quantity of waste on the farm is burnt to clear the field, contributing to environmental harm and global warming. The study aims to develop a technological solution for crop waste management (CWM) by designing and developing an IoT-enabled crop waste mulching machine. This initiative addresses the environmental and health issues caused by burning crop waste on farms. The research involves designing and developing an IoT-enabled mulching machine that can be attached to the back side of a tractor. The machine consists of power-transmitting elements, supports, and mechanisms to distribute mulching material evenly onto the plant bed. It incorporates advanced IoT load cell sensors, soil moisture sensors, and proximity sensors to optimize the mulching process based on soil moisture content and to prevent machinery blockages. The IoT-enabled mulching machine effectively manages crop waste by utilizing it in mulch, thus preventing the harmful practice of burning waste. This machine ensures a more efficient, safer, and environmentally friendly approach to mulching, offering significant improvements over traditional manual mulching methods.
The novelty of this research lies in integrating IoT technologies within mulching machine. The mulching machine uses sensors to automate and optimize the mulching process, representing a significant technological advancement over conventional methods. The study offers practical benefits by reducing labour requirements, minimizing the risk of injuries, and ensuring a more uniform mulch application. This technology facilitates more sustainable farming practices, aligning with global sustainability goals. The study can potentially revolutionize the agricultural equipment manufacturing industry (AEMI) by shifting the focus toward environmental sustainability. It promotes replacing plastic film mulching machines with more eco-friendly crop waste mulching solutions. This technology has the potential to reduce air pollution, carbon emissions, and mitigate climate. It also enhances soil health through better mulching practices.

Chemical Durability And Mechanical Properties Of Cementitious Matrices Containing Ashes Obtained After Combustion Of Waste From Moukondo Landfill In Brazzaville, Republic Of Congo.

The regular burning of solid waste in the open air and on the ground is commonplace in the Republic of Congo. Burning waste produces pollutants and ashes that can be hazardous to the soil and surrounding waters. Inadequate management of the ash generated by the open burning of household waste results in site pollution, particularly heavy metal contamination (Pb, Ni, Cr, Cu, Zn...). The aim of this study is to develop cementitious matrices containing burnt ashes that are sufficiently effective to retain the heavy metals contained in these ashes in their structure. To this end, in order to assess the chemical durability of these cementitious matrices, we carried out static leaching tests at pH=4 and 7 at 25°C in distilled water on the raw ashes firstly, and then on the 24 cementitious matrices synthesized with different ash/cement/lime ratios. The mechanical durability of the cementitious matrices was assessed using flexural and compressive strength tests. The leaching results obtained demonstrated the effective immobilization of heavy metals in cementitious matrices, whose leachates contain very low levels of heavy metals compared with those of raw ash. Flexural and compressive strength tests showed an improvement in strength from 25°C to 60°C. Several cementitious matrices doped with waste ashes show flexural strengths higher than the recommended standard for flexural strength EN1339 (5 MPa) and compressive strength X31-211 (1 MPa) after 28 days curing at 60°C

Effects of pyrolysis temperature on the photooxidation of water-soluble fraction of wheat straw biochar based on 21 ​T FT-ICR mass spectrometry

Biochar, formed through the pyrolysis or burning of organic wastes, has a complex chemical composition influenced by feedstock, pyrolysis temperature, and reaction conditions. Water-soluble, dissolved black carbon species released from biochar comprise one of the most photoreactive organic matter fractions. Photodegradation of these water-soluble species from wheat straw biochar, produced at different pyrolysis temperatures in laboratory microcosms, resulted in noticeable compositional differences. This study characterized water-soluble transformation products formed through the photodegradation of wheat straw biochar pyrolyzed at 300, 400, 500, or 600°C by electrospray ionization 21 ​T Fourier transform ion cyclotron resonance mass spectrometry (21T FT-ICR MS). We also evaluated global trends in the toxicity of these water-soluble fractions using MicroTox™ to assess the impacts of pyrolysis temperature. Additionally, we examined biochar surface morphology after photodegradation and observed minimal change after irradiation for 48 ​h, though the total yield of water-soluble biochar species varied with pyrolysis temperature. Trends in toxicity observed from MicroTox® analysis reveal that water-soluble photoproducts from biochar produced at 300°C and 900°C are nearly three times as toxic compared to dark controls. The ultrahigh resolving power of 21T FT-ICR MS allows for the separation of tens of thousands of highly oxidized, low-molecular-weight (<1 ​kDa) species, showing that photoproducts span a wider range of H/C and O/C ratios compared to their dark analogs. This study highlights the impacts of photodegradation on the molecular composition of water-soluble biochar species and underscores the influence of pyrolysis temperature on the quantity and composition of dissolved organic species.

Safety assessment of introducing radioactive waste incineration facilities in Korea: An off-site resident dose evaluation

As nuclear power technology advances, radioactive waste accumulation rises, necessitating measures to alleviate strain on disposal facilities and minimize waste management costs. Analysis of radioactive waste composition revealed that combustible waste comprised the largest proportion (45 %), with incineration demonstrating high reduction efficiency for this fraction. In order for a radioactive waste incineration facility to be introduced, it is necessary to evaluate the safety of gas radioactive effluent generated during city operation. Evaluation criteria have already been established and methodologies also exist, but these results greatly depend on the area where the incineration facilities are located, the waste to be treated, the operation method of the facilities. Accordingly, this study assumed annual throughput and radionuclide concentrations based on the radioactive waste stored and generated in Korea. The centralized operation method at a specific site was compared with the decentralized operation method employed at all sites. Post-incineration, the impact of radionuclides released from the facilities was analyzed against Nuclear Safety and Security Commission standards, confirming the discharge standards and doses for single facilities and entire sites.

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.

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.

KARAKTERISASI KOMPOSISI KIMIA DAN POTENSI PEMANFAATAN CAMPURAN TANAH GAMBUT KALIMANTAN TIMUR DENGAN FLY ASH DAN BOTTOM ASH UNTUK PERTANIAN

The utilization of coal combustion waste, specifically fly ash and bottom ash, as a soil amendment offers an opportunity to enhance the fertility of peat soils in East Kalimantan, which typically have low levels of essential nutrients such as nitrogen (N), phosphorus (P), and potassium (K). This study aims to evaluate the impact of adding coal ash on peat soil's chemical composition and quality as a growing medium. The chemical composition analyzed includes alumina (Al₂O₃), silica (SiO₂), phosphorous anhydride (P₂O₅), iron(III) oxide (Fe₂O₃), and calcium oxide (CaO). X-ray Fluorescence (XRF) was used to determine changes in nutrient content. The results indicate that adding coal ash increases the levels of potassium (K) and silica (SiO₂), but decreases the levels of nitrogen (N) and phosphorus (P₂O₅). Additionally, adding coal ash affects soil pH, which impacts nutrient availability. These findings indicate that while coal ash can enhance soil enrichment with potassium and silica, its impact on nitrogen, and phosphorus must be carefully managed to optimize fertilization and promote healthy plant growth.

Seasonal variation and size distribution of aromatic acids in urban aerosols in Beijing, China

Aromatic acids are an integral component of organic acids in the atmosphere, contributing to the formation of climate-altering brown carbon (BrC). To better understand the sources and formation processes of aromatic acids, we collected size-segregated particulate matter samples in urban Beijing from April 2017 to January 2018, which were analyzed using solvent-extraction followed by gas chromatography/mass spectrometry. Phthalic acid (o-PhA) had the greatest average annual concentration, followed by terephthalic acid (p-PhA), 4-hydroxybenzoic acid (4-OHBA), dehydroabietic acid (DA), syringic acid (SA), 3-hydroxybenzoic acid (3-OHBA), isophthalic acid (m-PhA), and vanillic acid (VA). We identified distinct seasonal variations in aromatic acids, with o-PhA peaking in summer due to photochemical activity, while p-PhA and 4-OHBA elevated in autumn and summer, respectively, influenced by open waste and biomass burning. Wintertime variations in all aromatic acids were driven by complex meteorology and increased anthropogenic emissions, including rural biomass burning for cooking and heating. Particle size distribution of aromatic acids was affected by seasonal agricultural activities and dust storms, multiple emission sources, and formation mechanisms. The o-PhA has predominantly bimodal distribution, with diverse sources and complex formation mechanisms including gas- and aqueous-phase chemistry. The applicability of o-PhA as a tracer for specific secondary organic aerosols has been questioned due to its potential primary sources. The 3-OHBA, 4-OHBA, VA, SA, and DA exhibited bimodal or trimodal patterns during haze and non-haze periods across different particle size ranges. The seasonal variation in VA/SA and VA/4-OHBA ratios demonstrated the complexity of biomass burning types, influenced by season, particle size, meteorological conditions, and combustion sources.

Contribution of plastic solid components to volatile organic compounds formation during plastics combustion

The combustion of plastic waste releases volatile organic compounds (VOCs) that are harmful to human health. However, information on the micro-mechanisms of VOC formation remains lacking. Here, the study hypothesized and verified the relationship between VOC formation and solid component degradation during plastics combustion. The VOCs released during plastics combustion exhibit characteristics such as low carbon content (nc< 10), volatility (9μgm-3 < log10C0 < 11μgm-3), and medium oxidation degree (−1.5 <OSC¯ < −0.5). The dominant VOCs ketones/aldehydes/acids (33-43%) may be attributed to the depolymerization of the polymer structure of plastics, the oxidation of C-O/C=O groups, and the secondary cleavage of gaseous oxygen-containing macromolecules. The VOCs released from the combustion of polyethylene terephthalate (PET) and poly(butyleneadipate-co-terephthalate) (PBAT) contained more aromatics than polyethylene (PE) and polypropylene (PP). And the temperature response of aromatics released from PET and PBAT lagged other VOCs compared that of PP and PE. However, compared to biomass thermal conversion, combustion of plastics releases fewer aromatics and nitrogenous compounds. Collectively, this work shows that the formation mechanisms of VOCs contributed by the solid components during plastic combustion are similar for PET and PBAT due to their similar chemical structures. The proposed mechanism in this paper will provide insight into the control of contaminants during plastic combustion.