Solid Waste Treatment Research Articles

Analysis of Solid Waste Treatment Practices in Footwear Factories

In this research, the practices adopted in two footwear industries, located in the southern region of Brazil, Vale do Sinos, to treat solid waste were investigated. Scientific literature, either national or international, converges on the perception of relevance of the environmental impact generated in this production chain, both due to the total volume of shoes that are manufactured and sold annually, and in view of the difficulties related to the disposal of footwear, at the end of its useful life. From this perspective, this study is justified and aims to identify and analyze, in the light of the reviewed scientific literature, which deals with waste from the footwear industry, the practices adopted in the treatment of solid waste in that economic sector. In order to achieve the objective, a case study strategy was carried out in two companies, using a qualitative approach, with the collection of empirical data through semi-structured interviews with organizational managers, indicated by the management of the organizations, in addition to documentary survey and participant observation systematic. The results showed that the two companies, one large and the second small, have a clear perception of the need to adopt sustainable practices and have already made several adjustments to the organizational system to promote alignment with sustainability principles. However, the actions and initiatives adopted to date show that the two organizations are still at an early stage of sustainability, especially in the solid waste treatment process.

Upflow Anaerobic Sludge Blanket (UASB) reactors for Bio-methane production from limed tannery fleshings: Lab and pilot scale reactors

The Upflow Anaerobic Sludge Blanket reactor is a viable high-rate anaerobic digestion design for the treatment of different wastewater with low to high solubility. This can also be used for the treatment of solid wastes with less HRT. In this study, the performance evaluation of a lab-scale UASB reactor was carried out for different hydraulic retention times of 24, 21, 18, 15 and 12 h for obtaining the best HRT for tannery fleshings. The gas production varied between 3.7 – 4.5 L with a methane content of 64.31 – 67.72%. It was observed that the maximum gas production was at 18 h HRT and this optimized condition was applied to the pilot-scale UASB reactor. The performance evaluation of the pilot-scale UASB reactor was carried out with an HRT of 18 h. The gas production of 450 ± 50 L, the maximum specific gas production of 0.274 m3/kg of VS destroyed and 0.239 m3/kg of TS destroyed was obtained and the maximum biogas productivity of 0.495 L was observed at 18 h HRT with the highest methane content of 67.86%. The payback period of the pilot scale reactor is 3.2 years.

Exploring alkaline serine protease production and characterization in proteolytic bacteria Stenotrophomonas maltophilia: Insights from real-time PCR and fermentation techniques

This study focuses on identifying a potent microbe for efficient alkaline protease production, characterizing its properties, and investigating protease gene expression across diverse culture conditions. Stenotrophomonas maltophilia strain GEBN5 is methodically chosen and refined for peak alkaline protease production at 36 h (75.37 U/mL) in basal media employing precise adjustments in temperature, pH, incubation time, and carbon/nitrogen sources, achieving a noteworthy maximum protease activity of 97.03 U/mL in shake flask culture. Alkaline protease gene (StmPr1) up-regulation was explored via Real-time PCR under varied culture conditions (pH, temperature, carbon, and nitrogen sources) in a 2L fermenter at 150 rpm, resulting in peak protease production of 113 ± 0.53 U/mL in batch culture at pH 9.0, 35 °C, with sucrose and casein, respectively. The characterization data demonstrates exceptional stability of the current protease across a broad pH (9.0–11.0) and optimum temperature of 35 °C, highlighting its promising applications in diverse industrial and biotechnological settings. A higher instability complex of protein 28.59 was revealed by in silico analysis, indicating prolonged stability during hydrolysis and a wide range of potential uses. The purified protease demonstrates superior compatibility (45%–88% residual activity) with diverse detergent brands treated for 45 min at 40 °C, indicating its potential as a valuable additive for enhanced washing efficacy. Current research offers a novel strategy to boost protease production, presenting a promising alternative to chemical dehairing in leather industries and solid organic waste treatment. This approach holds the potential for mitigating environmental pollution through bioremediation.

Green disposal of waste smartphone protective film: efficiency, mechanism, bench-scale test and secondary waste reutilization

The manufacture and obsolescence of smartphones produce numerous waste plastic accessories (e.g., waste smartphone protective film (WSPF)), possessing immense potential for recycling. However, available recycling technologies have limitations such as substrate damage and secondary pollutant generation. The present study aimed to develop a green disposal method that not only recycled polyethylene terephthalate (PET) from WSPF, but also reused the stripped polyacrylate (PAA) adhesive as an adsorbent to reduce solid waste generation. When the WSPF was treated in 1 M NaOH solution at 90°C, the PAA hydrolyzed to two main by-products of 1-butanol and 2-ethylhexanol, weakening the binding strength between PAA and PET and then efficient separation of them. Further bench-scale test revealed that over 97.2% of detachment efficiency toward PAA was achieved during continuous treatment of 17 batches of WSPF (200 g for each) without supplement of NaOH and generation of wastewater. Meanwhile, the economic evaluation indicated that the recycling method would generate a net profit margin of 647% for the second year without considering the incurrence of new cost and input. Additionally, the pyrolysis of waste PAA enabled its conversion into potential adsorbent, which showed 2 to 4 times enhanced adsorption capacity toward styrene and ethyl acetate after modification with NaOH solution. This study provides a green method for recycling waste plastics and inspires a referable solution for solid waste treatment in the smartphone industry.

From Simulation to Reality: CFD-ML-Driven Structural Optimization and Experimental Analysis of Thermal Plasma Reactors

Thermal plasma reactors offer an environment of high temperature, enthalpy, and reactivity, making them highly efficient for solid waste treatment and promising for clean energy production from municipal and industrial waste. Optimal geometrical parameters of the reactor can enhance waste treatment and reactor performance. This study presents a comprehensive analysis of 11 key geometrical parameters of a thermal plasma reactor. Utilizing CFD Fluent software, numerical simulations were conducted to generate a dataset. Subsequently, a predictive model focusing on the average temperature in the core melt zone was trained using six Machine Learning (ML) algorithms. The Particle Swarm Optimisation (PSO) algorithm optimized the hyperparameters of the Gradient Booster Regression (GBR) model, which was combined with a Genetic Algorithm (GA) to identify the reactor's optimal geometrical parameters. A DC arc plasma torch-solid waste thermal plasma reactor treatment system was established on this basis. The study also explored the effects of gasification coefficient, reaction temperature, and thermal plasma jet mode on system performance. Findings indicate that the PSO-GBR model achieved the highest prediction accuracy, with the temperature in the core reaction zone reaching 3621K. The deviation between numerical simulations and machine learning predictions was a mere 1.3%. Enhancing syngas yield and energy efficiency is achievable by controlling reaction temperature and increasing the gasification coefficient. A laminar plasma jet mode, at equal power, provides a more effective reaction environment. The accuracy and reliability of the machine learning-driven regression model and optimization results are significant in guiding the optimal design of plasma reactors and advancing waste-to-energy conversion processes.

Identification of the effect of electric pulse discharges on the recycling of household glass

The work was devoted to the study of the recycling of household glass waste by the electric pulse method. Cullet and glass containers were considered as the object of research. Cullet and used glass containers are considered suitable for recycling among solid household waste. The treatment of solid household waste was carried out with the formation of electrical discharges in an inhomogeneous environment (glass fragments and glass products in an aqueous environment). The experiments were carried out at different values of pulse discharge voltage (from 12 kV to 37 kV), capacitor bank capacity (from 0.4 to 1.2 µF), number of pulse discharges (from 250 to 1,000) and frequency (from 0.3 Hz to 2 Hz). The dependence of the output of the finished product on the parameters of electric pulse discharges has been revealed from the research results. According to the main results of the research work, it was found that as the parameters of electric pulse discharges increase, the yield of the finished product increases. The data made it possible to assign effective parameters for processing cullet and glass products using the electric pulse method. The granulometric composition of the powder material obtained by this method has been determined. A product with a diameter of the largest fraction of 5-8 mm and a diameter of a small fraction of 0.4 mm and 0.7 mm was obtained. The results of the experiment can be used in research on saving natural resources, energy conservation and solving environmental problems of solid waste recycling. Powdered glass is used as a thermal insulator and decorative material in construction. In addition, crushed glass is used in the production of concrete as an additional raw material.

Utilization of carbonated alkaline solid wastes in ordinary Portland cement-metakaolin-limestone ternary mixture: Underlying the role of low grade-sustainable calcium carbonate sources

Alkaline solid wastes are widely generated as by-products annually from construction demolition, steel making, and metal refining industries. Consequently, there is high pressure on their disposal and environmental protection. Carbonation treatment of alkaline solid wastes provides a potential way to valorize CO2 and produce low-grade artificial limestone particles. This study investigates the utilization of carbonated alkaline wastes, including recycled cement fines, steel slag, iron recycled steel slag, and magnesium slag in green ternary cement (limestone-metakaolin-cement system) production. The detailed characterization of carbonated alkaline solid wastes and the performance of metakaolin-cement based ternary systems were evaluated. The reaction mechanism of carbonated alkaline wastes in metakaokin-cement based binder is proposed. The results indicated carbonated alkaline solid waste powder containing relatively low calcite (14.4%–50.38%) and negative surface charges. In addition, the amount of reactive Si at Q3 and Q4 were observed. The precipitated calcite on the surface of particles resulted in the deterioration of the workability of ternary mixtures compared to natural limestone. However, the equivalent amount of CO3-AFm phases produced by precipitated calcium carbonate and additional hydrates from the reaction of amorphous silica in carbonated alkaline solid wastes contributed to a comparable mechanical performance (49.5 MPa–50.82 MPa) and compact microstructure of ternary binders. Carbonated alkaline solid wastes can be a sustainable component to replace natural limestone in green ternary cement production.

An assessment of the consumption and disposal of medications home use

In the current scenario, the market society, an economic model consolidated in many parts of the world, faces some social and environmental challenges, such as the solid waste disposal and treatment of different residues generated daily, especially in big cities. In Brazil, 4,540 municipalities provided medical waste collection services, and more than a third (36.2%) sent the MS to landfills, dumps, and septic ditches. This issue faced by municipalities is challenging as they try to promote less damaging management that impacts the environment due to urban demography and fragile socio-environmental conditions. Action as reverse logistics is a strategy that enables the return of after-sales and post-consumption waste to the business environment and the productive sector, promoting the circular economy, the recovery of waste, the life cycle of products, decrease in the use of materials, reduction of environmental impacts, compliance with current regulations and non-contamination of the environment. The assessment of unusual medications and population knowledge allows drawing an overview of the disposal of uncommon medications for home use by an electronic questionnaire addressing different questions, referring to the identification of the user's profile, various forms of consumption, storage, and disposal of medication waste, and knowledge about the local regulation. Most medications consumed by the population are antibiotics, analgesics, fever reducers, and pain relief without medical recommendations, not used to seeing the expiration date, and not reading the drug leaflet. The assessment population could only pay a little for the additional tax for final medication waste disposal. Most of the participants disposed of the unusual medications in the household garbage. Finally, the reverse logistics implementation of medication waste in Brazil will be a significant challenge for decreasing the environmental impacts and pollution because of the culture of the local population.

Prediction and Feed-In Tariffs of Municipal Solid Waste Generation in Beijing: Based on a GRA-BiLSTM Model

To cope with the increasing energy demand of people and solve the problem of a “Garbage Siege”, most cities have begun to adopt waste power generation (WTE). Compared to other WTE technologies, incineration has proven to be the most efficient technology for municipal solid waste (MSW) treatment. Therefore, to further explore the economic feasibility of MSW incineration plant construction, this study established a multi-factor prediction of MSW generation based on the GRA-BiLSTM model. By fully considering the relationship between the change in feed-in tariff (FIT) and the building of an incineration plant in Beijing, the economic feasibility of building an incineration plant is discussed based on the three scenarios set. The experimental results showed that (1) the combined model based on the GRA-BiLSTM showed good applicability for predicting MSW generation in Beijing, with MAE, MAPE, RMSE, and R2 values of 12.47, 5.97%, 18.5580, and 0.8950, respectively. (2) Based on the three scenarios set, the incineration power generation of Beijing MSW will show varying degrees of growth in 2022–2035. In order to meet future development, Beijing needs to build seven new incinerators, and the incineration rate should reach 100%. (3) According to setting different feed-in tariffs, based on the economic feasibility analysis, it is found that the feed-in tariff of MSW incineration for power generation in Beijing should be no less than $0.522/kWh. The government should encourage the construction of incineration plants and give policy support to enterprises that build incineration plants.

Cooperative treatment and resource utilization of municipal solid waste by industrial coke ovens: Effects of doping ratio and management

For the collaborative treatment and resource utilization of an industrial coke oven on municipal solid waste (MSW), this study used MSW to prepare refuse-derived fuel (RDF). The influence of different mix ratio between RDF and coal on coking products was considered, and technical and economic analyses were conducted. The results showed that under the low mixture ratio (3%), the pyrolytic carbon obtained basically met the class III standard of metallurgical carbon. In the experiment of medium mixture ratio (25%, 30%, 35%), the product contained a certain amount of calorific value, lower than that of the metallurgical coke. It might be that the ash content increased, and such product can be used for civil coke or chemical coke. When the mixture ratio was 100%, the calorific value of pyrolysis carbon was 7.53 MJ/kg, representing 25.7% of the calorific value of ordinary coke. The gas production rate of the discharged gas was 0.35, and the calorific value is 14.0 MJ/kg, reaching 73.6% of the coke oven gas. Under the condition of no coal input, the MSW was converted into usable energy. The results demonstrated that coke oven pyrolysis with 100% RDF addition is the most feasible way to recycle resources and energy.

Metallurgical slag used for efficient growth of Chlorella pyrenoidosa to achieve CO2 conversion to biodiesel

AbstractMetallurgical slag such as solid waste generated in the steel industry carries environmental pollution risks, but it is rich in nutrients required by microalgae. Metallurgical slag used for carbon capture and biomass energy conversion has multiple benefits: (i) reduction and harmless treatment of metallurgical solid waste, (ii) assisting in carbon neutrality by efficient carbon fixation, and (iii) production of biodiesel from CO2. In this study, AOD, BOF, BFS, HVS, and VTS slag were applied to culture Chlorella pyrenoidosa (C. pyrenoidosa) with the regulation of growth, carbon fixation, and lipid synthesis. An excellent fixed amount of CO2 with 94.59 mg is obtained from C. pyrenoidosa biomass at BOF slag added (mass ratio of CO2 captured/microalgae/slag with 1.99/1.00/10.53) since high Ca/Mg mass ratio of 419 (8.38 mg/L Ca and 0.02 mg/L Mg), no Cr and low concentration of Al (0.04 mg/L) contribute to regulating antioxidant enzyme activity (SOD and POD) to resist ROS and improving PEPC activity to reduce carbon flux toward lipid to promote biomass synthesis. Both metal concentrations from Ca (5.86 mg/L), Mg (0.05 mg/L), Al (0.42 mg/L), and Cr (0.006 mg/L) and suitable pH (10.53) in AOD leaching solution at solid/liquid ratio of 0.5 g/L change carbon flow toward efficient lipid synthesis (47.07 wt%) by continuously providing raw materials and energy by regulating ACC, ME, and PEPC activities. High value‐added biodiesel with high concentrations of C16 and C18 methyl esters from lipid of C. pyrenoidosa is achieved, following other ecological and economic benefits including 197 mg CO2 captured and 2198 mg AOD applied with harmless. In this study, C. pyrenoidosa is cultured with elements from metallurgical slag solid waste, which promotes C. pyrenoidosa efficient carbon fixation to assist in carbon neutrality, and provides guidance for CO2 conversion to high‐value‐added products with low cost.

A cleaner-sustainable process for recovering valuable elements from steel slag with acetic acid: Leaching studies and multi-value-added products

Steel slag (SS), a hazardous solid waste produced by the steelmaking industry, contains a large number of valuable metals but generates a potential threat to the environment. This research focuses on a cleaner-sustainable process to recover valuable elements, including calcium (Ca), magnesium (Mg), aluminum (Al), and iron (Fe), from SS by acetic acid leaching, and develop new products. The single-factor experiment and kinetic analysis were employed to determine the leaching characteristics of SS, optimize the leaching processes, investigate the influence of various leaching conditions, and clarify the constraints of leaching kinetics. The results indicated that the leaching rate of Ca, Mg, Al, and Fe was 76.24 %, 67.19 %, 54.97 %, and 28.91 %, respectively, under the optimal leaching conditions. Besides, the apparent activation energies of Ca, Mg, Al, and Fe were 26.20 kJ/mol, 26.26 kJ/mol, 23.37 kJ/mol, and 14.76 kJ/mol, respectively, and the whole leaching process was found to be controlled by the diffusion and interfacial chemical reaction. Meanwhile, a residue with admirable surface areas was obtained after the leaching stage. The leachate was co-precipitated by sodium hydroxide (NaOH), and multi-value-added Mg-Fe layered double hydroxide (Mg-Fe LDH) was synthesized. This work demonstrates the potential of hydrometallurgical processes for the treatment of SS, which is of considerable importance to the harmless treatment of industrial solid waste and provides insights into strategies for the utilization of secondary resources.

Forecasting the Mitigation Potential of Greenhouse Gas Emissions in Shenzhen through Municipal Solid Waste Treatment: A Combined Weight Forecasting Model

As a significant source of anthropogenic greenhouse gas emissions, the municipal solid waste sector’s greenhouse gas emission mode remains unknown, hampering effective decision-making on possible greenhouse gas emission reductions. Rapid urbanization and economic growth have resulted in massive volumes of municipal solid trash. As a result, identifying emission reduction routes for municipal solid waste treatment is critical. In this research, we investigate the potential of municipal solid waste treatment methods in lowering greenhouse gas (GHG) emissions in Shenzhen, a typical Chinese major city. The results showed that the combined treatment of 58% incineration, 2% landfill, and 40% anaerobic digestion (AD) had the lowest greenhouse gas emissions of about 5.91 million tons under all scenarios. The implementation of waste sorting and anaerobic digestion treatment of organic municipal solid waste after separate collection can reduce greenhouse gas emissions by simply increasing the incineration ratio.

Residual, sequential extraction, and ecological risk assessment of some metals in ash from municipal solid waste incineration, Vietnam

Abstract Incineration plants for electricity generation have offered a solution to the challenges of domestic solid waste treatment in many countries. However, their emissions, fly ash (FA) and bottom ash (BA), have had a detrimental impact on environmental quality. This study investigated the morphology, element composition, and concentration of metals in FA and BA from municipal solid waste incineration plants using scanning electronic microscopy/energy-dispersive X-ray and inductively coupled plasma mass spectrometry techniques. It also evaluated the distribution ratios of metal species across five fractions: exchangeable, carbonate-bound, oxide-bound, organic-bound, and sulfide-bound, and residual. The total metal content in both FA and BA was comparable, with calcium having the highest concentration (28,170–135,130 mg·kg−1 dry weight) and silver having the lowest (5.26–19.3 mg·kg−1 dry weight). However, the percentage proportion of metals differed between the extracted fractions. Except for cadmium in FA, ecological risk assessment indicated low direct bioavailability and potential risk of metals in both FA and BA. These findings contribute to the hazard assessment of FA and BA generated from waste incinerators and provide a scientific basis for developing treatment techniques for this type of waste.

Pyrolysis, a recovery solution to reduce landfilling of residual organic waste generated from mixed municipal waste.

Despite policies to restrict the mixing of organic waste with other general waste and improve its separation at source, municipal solid waste still contains a high proportion of organic waste. The residual organic waste is generated as a by-product of the mechanical treatment of municipal solid waste (MSW) and is mainly disposed in landfills after composting. Its reuse and recovery status varies across European countries. Most countries restrict the use of biostabilised residual waste (BSRW) to landfill cover, whereas others have regulated it as marketable compost. Crucially, BSRW is set to lose its "recycled" status under the revised European Union waste framework, with probably tighter restrictions and increased costs imposed for the landfilling of organic waste. Our research aimed to investigate pyrolysis as an alternative technology to treat the 10-40mm fraction of BSRW (representing 50% of BSRW generated). Pyrolysis at 700°C was carried out and feedstock and pyrolysis products were characterized. Mass and energy balances showed that pyrolysis produced hot vapour/gas whose combustion may render the pyrolysis process energetically sustainable. Biochar comprises 30-50% of BRSW mass after removal of glass, metal and stones. Our results indicate that pyrolysis has the potential to create options for contributing to reduce the landfilling of BSRW; however, the presenceof residual impurities may limit biochar applications.

Assessment of the Status of the Existing Solid Waste Collection, Transportation Disposal and Treatment Practices in Soroti District, Uganda

Assessment of the Status of the Existing Solid Waste Collection, Transportation Disposal and Treatment Practices in Soroti District, Uganda

Fly ash treatment via conventional and microwave-assisted organic acid leaching: kinetics and life cycle assessment.

Heedless disposal of oil-based fly ash contributes to the contamination of the air, water, and soil. Acid leaching of industrial solid wastes is recognized as a versatile, cost-effective, and environmentally friendly solid waste treatment approach. The present study investigated the viability of conventional leaching (CL) and microwave-assisted leaching (MAL) of predominant heavy metals from Mazut-burnt fly ash. For this purpose, the practicality of four organic acids with various specifications (ascorbic, gluconic, citric, and oxalic acids) on the dissolution efficiency of fly ash components was examined. Utilization of oxalic acid led to achieving full V recovery, complete Fe removal, and Ni enrichment in the residue in both CL and MAL setups. The Ni content of the sample was enriched from 6% in the calcinated sample to 23.7% in the oxalic acid leaching residue. Using citric acid resulted in the co-extraction of V, Ni, and Fe with nearly 70% V, 50% Ni, and 89% Fe dissolved in CL. The dissolution efficiencies were slightly lower in MAL. Oxalic acid was selected as the most promising organic acid reagent for fly ash treatment, so its CL kinetics was studied and defined by the shrinking particle model. The model showed that the controlling steps in the leaching of V differ over time, changing from a chemical reaction before 60min to fluid film diffusion or mixing afterward. The kinetic study proved MAL as an effective technique in overcoming the leaching kinetic barriers. A life cycle assessment study was conducted to determine the environmental impacts of the proposed process. Accordingly, the MAL using oxalic acid was the most environmentally friendly process among the studied ones, and the utilization of microwaves leads to the reduction of the leaching processes' environmental impacts by decreasing the processing time.

Risk Management Strategies for Waste-to-Energy Projects Utilizing BOT Models

Since the 1990s, with the implementation of the reform and opening up policy, the rapid development of China's economy, the progress of urbanization is getting faster and faster, and as one of the urban wastes, the treatment of domestic waste has also attracted more and more attention. The municipal solid waste incineration treatment, and the heat generated after combustion is used to generate electricity, referred to as "garbage incineration power generation", because this way can make the waste to reduce, harmless, and can be converted into part of the electricity, because it is widely used in the treatment of municipal solid waste by local governments. Due to the shortage of government funds, most domestic waste incineration projects are implemented in BOT mode. Waste incineration power generation projects are often a large investment, for investors, the recovery period is long, the technical requirements are high, the investment agreement signed with the government is also very complex, coupled with the imperfect supporting laws and policies in China, so that the process of waste incineration power generation projects have many problems and risks, through the operation, construction, investment and other links. Based on the theoretical content of risk management in project management and combined with practical cases, this paper puts forward countermeasures and suggestions for important risks in the project, so as to analyze and discuss the risks of garbage incineration BOT project. Firstly, this paper investigates and collates the research situation of relevant projects at home and abroad, and systematically summarizes the project research results from three aspects, namely, BOT risk management of waste incineration power generation projects, BOT model of projects and BOT project risk research. Secondly, the multi-case study method was used to analyze the risks of 3 typical waste-to-power generation BOT projects, collect risk factors, construct risk aggregation, and summarize 5 types of key risks and 14 kinds of risks. Then, according to the BOT agreement signed with the government side, the specific risk management method is proposed. The goal of this study is the LF waste incineration power generation project. The author participated in the project and identified and evaluated the project risks through risk list and hierarchical analysis, so as to find out the main risks in the project such as government risk, public opinion risk, completion risk and operational risk. In addition, in combination with the project risk, specific risk coping strategies are proposed according to the risk coping strategies proposed in the paper and the actual situation of the project, so as to reduce the degree of project risk and reduce risk losses. For other similar projects in China, there is reference and reference significance and value.

Performance evaluation of trommel screens: A case study of a municipal solid waste treatment plant

The efficient and effective operation of trommel screens is essential for the economic and environmental sustainability of mechanical biological treatment (MBT) based solid waste treatment plants. The present study evaluated the performance of four trommel screens (aperture sizes of 80, 32, 16, and 4 mm) being used at the MBT plant of the Municipal Corporation Karnal, India. The performance of trommel screens was evaluated at a fixed speed of rotation and inclination angle. For optimum performance, trommel screens must be operated at a particular range of feed rates with regular cleaning every four hours of operation. The organic recovery achieved by 80 mm and 32 mm aperture size trommel screen was 26.95 % and 95.82 %. The organic quality improvement achieved by 80 mm and 32 mm trommel screens was 122.50 % and 108.89 %. The trommel screen's heating value improvement and energy recovery ranged from 70.68 % to 135.16 % and 28.27 % to 98.74 %, respectively. The oversized fractions of trommel screens of opening sizes 80 mm and 32 mm meet the fuel specification prescribed by the Indian Solid Waste Management Rules 2016. The trommel screen's Specific Energy Consumption (SEC) ranged from 0.63 kWh/tonne to 5.66 kWh/tonne. The learnings and outcomes of this study are helpful for designers, policymakers, operators of solid waste treatment plants, and researchers.

Preparation of polystyrene and silane-modified nano-silica superhydrophobic and superoleophilic three-dimensional composite fiber membranes for efficient oil absorption and oil-water separation

Oily solid waste and wastewater are two kinds of contaminants that seriously endanger the environment and the general public. Recently, superhydrophobic and superoleophilic materials have attracted extensive attention owing to their exceptional oil-water separation capabilities. In this study, we demonstrated a simple, low-cost, and high-economic efficiency method to prepare nanosilica (SiO2) from dye diatomite filter aid waste (DDW) and silanize it with octadecyltrichlorosilane (OTS) to form hydrophobic nanosilica (hSiO2) by solution impregnation. Polystyrene/hydrophobic nanosilica (PS/hSiO2) composite fiber membranes with a rough surface and low surface energy were prepared by electrospinning. The prepared PS/hSiO2 water contact angle can reach 166.6°, showing superhydrophobicity and excellent adsorption capacity for various common oils. The maximum oil absorption capacity for transformer oil can reach 136.4 g/g. Importantly, the oil absorption process of the nanocomposite is selective, fast, and efficient, and it can be used for the purification of oil-contaminated water. In addition, it also demonstrates remarkable durability and stability in strong acid and alkali solutions. This strategy of making oil-water separation materials from solid waste may offer a straightforward, cost-effective, and environmentally sustainable option for the treatment of solid waste, industrial oil wastewater treatment, and marine oil spill cleanup.