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Improving urban air quality is a pressing challenge in the Global South. A key source of air pollution is the informal burning of household waste. Reducing informal burning requires governments to develop formal systems for waste disposal and for residents to adopt new disposal behaviors. Using a randomized experiment, we show that social competitions between pairs of neighborhoods in Nansana municipality, Uganda, galvanized leadership and inspired collective action to reduce informal burning. All 44 neighborhoods in the study received a public health campaign, while 22 treated neighborhoods were paired and competed to reduce waste burning over an 8-mo period. Treated neighborhoods showed a 24 percent reduction (95% CI: 11 to 35 percent) in waste burning relative to control neighborhoods at the end of the competition period. There is no evidence that treated neighborhoods experienced a rebound in waste burning several months after the competitions. Community leaders reported greater effort in coordinating residents and more pride in their neighborhood when assigned to the competition treatment. These results suggest that creating focal points for leadership and collective action can be an effective and low-cost strategy to address policy problems that require broad participation and costly behavior change.

The recycling of solid waste is widely regarded as the one of the most crucial issues of sustainability. This is particularly evident in the industrial sector, where the production of slags is huge and their handling presents a significant challenge. In this study, solid wastes from the industrial sector, namely ferrochrome slag (Fs) and fluorite tailings (Ft), were employed for the preparation of glass-ceramics by the sintering method. Three glasses were prepared by using the melt-quenching method, with a weight ratio of 60∼70 % Fs and 40∼30 % Ft (designated S30, S35, and S40, where the higher number indicates a greater Fs content). The sintering and crystallization behaviors of these glasses were characterized by hot-stage microscopy (HSM) and differential thermal analysis (DTA). It was observed that S40 glass exhibited a weak sintering capacity in comparison to that of S30 and S35 glass, which can be attributed to the robust crystallization propensity of S40 glass. The coarser glass frits were subjected to sintering experiments at varying temperatures, which demonstrates that the predominant crystalline phase is augite and that Cr 2 O 3 remains present in all sintered samples. Besides, a transition of the Cr 2 O 3 crystal into uvarovite was observed in S40 glass sintered at 1050 °C. The sintering time controlling experiment demonstrated that both wollastonite and the Ca-rich flow formed during sintering are vital for the formation of uvarovite. The formation of uvarovite can enhance the hardness of GCs. All GCs samples sintered at 1050 °C and 1120 °C exhibit comparable mechanical performance. [ABSTRACT FROM AUTHOR]

This research investigated the application of municipal solid waste incineration fly ash (MSWIFA), municipal solid waste incineration bottom ash (MSWIBA), and construction waste residue (CWR) as raw materials for the comprehensive conversion into municipal solid waste ceramics employing the SiO 2 -Al 2 O 3 -CaO-MgO (8 wt%) phase diagram. This study aimed to evaluate the influence of the addition of MSWIFA and sintering temperature on important ceramics properties, including linear shrinkage, water absorption, sintering range, and flexural strength. Additionally, relationships were established among these physical parameters using Pearson's correlation coefficient. The thermal behavior of the mixture was analyzed through automatic slag melting point tester and TG-DSC techniques. Furthermore, characterization of the crystalline phase transition and microstructure of sintered samples was performed by XRD, Factsage, and SEM. The results showed that both the addition of MSWIFA and the sintering temperature significantly influenced the crystal phase composition of the sintered ceramics. Moreover, the addition of MSWIFA and the sintering temperature had a significant influence on the pore structure of the ceramics. These ceramics exhibited exceptional properties, such as the extremely low water absorption rate of 0.08 % and the remarkable flexural strength of 124.78 MPa. Ceramics performance indicators were far higher than the requirements of China's national standard GB/T4100-2015. The sintering range had the capability to attain 30 °C, guaranteeing the feasibility of practical manufacturing processes. Furthermore, leaching concentration tests conducted on additive-free ceramic samples reveal a low risk of heavy metal contamination, as the heavy metals were effectively solidified within the crystalline and amorphous phases of the ceramics. The comprehensive utilization of MSWIFA, MSWIBA, and CWR for the production of fully solid waste ceramics not only yields cost reduction benefits but also promotes efficient utilization, presenting a feasible and highly promising approach to sustainable waste management. [ABSTRACT FROM AUTHOR]

Developing low-cost phase change composites (PCCs) with high performance is of significant importance in thermal energy storage. Herein, four PCCs were prepared with steel slag-fly ash solid wastes and eutectic salt (NaNO 3 -KNO 3), i.e., pure fly ash based PCC (pFA), pure steel slag based PCC (pSS), steel slag-fly ash based PCC (DSWM), and steel slag-fly ash-kaolin based PCC (HPCP). First, the optimal ratios of raw materials were predicted using the Facility for the Analysis of Chemical Thermodynamics (FactSage) software. Then, the composite's mechanical, thermal, and cyclic properties were characterized. The results indicate that the HPCP composite presents superior mechanical properties, with compressive strength and Young's modulus of 43.84 and 10563.86 MPa, respectively. Its thermal conductivity is 1.203 ± 0.054 W m−1 K−1, and after 40 thermal cycles, the mass and thermal conductivity decrease by 1.7 % and 5.2 %, respectively. The excellent properties of HPCP were due to the formation of a high-purity anorthite ceramic crystalline phase in PCC, which could minimize the defects of the porous medium, and reduce the leakage of encapsulated molten salts, thus enhancing the mechanical properties and cyclic thermal stability of the HPCP. This study can provide important guidance in preparing low-cost PCCs with industrial solid wastes. [Display omitted] [ABSTRACT FROM AUTHOR]

Secondary aluminum dross (SAD), a hazardous solid waste derived from the metal aluminum (Al) smelting process, contains 65−90 % aluminide and over 30 different impurity elements, thus being an alternative material for alumina ceramic production to replace traditional sources such as bauxite or industrial alumina powder. The presence of inherent impurities would seriously deteriorate the mechanical properties of ceramics prepared from SAD. This study proposed an innovative process involving grinding-alkali leaching-CO 2 -assisted in-situ precipitation of nano-alumina to effectively eliminate the influence of impurities on the ceramic mechanical properties. Grinding greatly reduced the median particle size from 67.4 to 3.17 μm, improving the particle structure and specific surface area. The active aluminum components were transferred from the interior of SAD particles to the surface to form nano-alumina by alkaline leaching and in-situ precipitation. The nano-alumina layer could completely coat the ground SAD particles. As a result, these impurities in SAD would not form the connected liquid phase but instead form isolated liquid phase points inside the particles during the high-temperature firing process. The sintering mechanism of ceramics changes from liquid phase sintering to solid phase sintering. The fracture mechanism of ceramics changes from intergranular fracture to transcrystalline fracture, and the mechanical properties of ceramics are greatly improved. Alumina ceramics sintered at 1500 °C showed the density, porosity, hardness and flexural strength of 3.42 g/cm3, 3.7 %, 1457 Hv, and 235 MPa, respectively. This process eliminates the negative effects of 21.54 % impurities in SAD and produces alumina ceramics that meet the 90 Al 2 O 3 ceramic standard. [Display omitted] • A process to prepare ceramics from SAD using in-situ nano-alumina precipitation. • Effect of impurities on mechanical properties of ceramics was eliminated. • The nano-alumina coating changes liquid phase sintering to solid phase sintering. • Alumina ceramic prepared from SAD met the 90 Al 2 O 3 ceramic standard. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) incineration bottom ash (BA) and molybdenum tailings (MTs) are bulk solid wastes that have low added value and is of a serious environmental concern. Hence, it is imperative to develop technology that potentially as convert these wastes into potential products that are safe to handle. In the present work, the goal is to synthesize glass-ceramics from BA and MTs without addition other supplement materials. The study attempts to assess the influences of raw material ratio and sintering temperature on the phase transformation, microstructure and properties of glass-ceramics. The synthesized product shows that diopside ferroan and anorthite were the dominant crystals, and the content of diopside ferroan and anorthite increased with an increase in the proportion of MTs. It was observed that the presence of Fe 2 O 3 and TiO 2 inside solid wastes promote nucleation facilitating growth of crystals. Diopside ferroan and anorthite distribute uniformly and are well interweaved, densifying the structure with favorable properties of glass-ceramics. At the optimal processing temperature the presence of Na 2 O and K 2 O in the raw materials act as fluxing agents that facilitate formation of liquid phase, that enhance diffusion and rate of crystallization. The optimal mass ratio of BA to MTs was 45:55 and the sintering temperature of 1000 °C, exhibited the best comprehensive properties of the glass ceramics. At the optimal conditions the flexural strength, Vickers hardness, bulk density and water absorption were observed to be 76.00 MPa, 5.77 GPa, 2.69 g/cm3 and 0.32 %, respectively. The leaching test proved stability of the glass ceramics, and hence can serve to be a potential way of utilizing the waste into a valuable product benefiting the environment and promoting sustainable growth. [ABSTRACT FROM AUTHOR]

Surrogate-assisted evolutionary algorithms have been widely employed to solve data-driven optimization problems. However, for offline data-driven optimization, it is very challenging to perform evolutionary search efficiently as well as accurately since no new data is available during the optimization process. To mitigate this issue, a multifidelity surrogates-assisted multi-objective particle swarm optimization (MFSa-PSO) algorithm is proposed in this paper. First, two low-fidelity models with convergence and diversity characteristics separately and a high-fidelity model are constructed to assemble multifidelity surrogate models. Second, by adopting the knowledge transfer strategy, the multifidelity surrogates-assisted two-archive multi-objective particle swarm optimization is conducted to search optimal solutions more exactly and effectively. Third, the output solution set is achieved by associating the solutions of two archives with reference vectors. Finally, the proposed MFSa-PSO is compared with some popular surrogate-assisted evolutionary algorithms on benchmark problems to verify its effectiveness and outperformance. Additionally, a real-world application of the municipal solid waste incineration process is carried out to verify the engineering applicability of MFSa-PSO. [ABSTRACT FROM AUTHOR]

Biohydrogen production by dark fermentation (DF) can be achieved using only indigenous bacteria from substrates or by adding an external inoculum. This study aims to provide new insights on the role of indigenous bacteria in DF process operation by investigating DF performances and microbiological aspects. DF tests are performed with only indigenous bacteria, with indigenous and exogenous bacteria and with only exogenous bacteria by inactivating indigenous bacteria by gamma irradiation. Sorghum irradiation reduces DF performances for both hydrogen (17.8 ± 12.8 versus 45.2 ± 1.7 mLH 2 /gVS added) and total metabolite (0.22 ± 0.01 versus 0.30 ± 0.01 gCOD/gVS added) yields. In contrast, no difference is observed with the organic fraction of municipal solid waste, suggesting a distinct role of indigenous bacteria for both substrates. Indigenous bacteria inactivation strongly modifies the metabolic routes and final bacterial community composition. This study proves the key role of indigenous bacteria in influencing metabolite production and bacterial composition. [Display omitted] • Successful inactivation of indigenous bacteria by gamma irradiation. • Lower performances of dark fermentation for irradiated sorghum. • No impact OFMSW irradiation on hydrogen yield and biomass bioconversion. • Metabolic and microbiological changes after irradiation of both substrates. • Lower reproducibility of DF experiments after indigenous bacteria inactivation. [ABSTRACT FROM AUTHOR]

The comprehensive utilisation of solid waste is a critical tool for environmental governance. As a major driver of economic development, industrial structure upgrading and technological innovation are also conducive to environmental governance. As a result, using statistical data from 30 Chinese provinces from 2009 to 2019, this article constructed a spatial econometric model and explored the links between industrial structure upgrading, technological innovation and comprehensive utilisation of solid waste. The results showed that: Industrial structure upgrading has a 'U'-shaped curve relationship that first inhibits and then promotes the comprehensive utilisation of solid waste. In the long run, upgrading industrial structures promotes the comprehensive utilisation of solid waste as a whole. Technological innovation has a significant moderating influence on the impact of industrial structure upgrading on the comprehensive utilisation of solid waste. [ABSTRACT FROM AUTHOR]

Porous geopolymer composite (E51) reinforced by E51 epoxy resin was prepared by well‐distributed dual‐blending using red mud, metakaolin, and slag as raw materials. The effects of E51 content on microstructure, porosity, mechanical properties, and thermal insulation properties of the porous composites were investigated. The addition of E51 changed the setting time and viscosity of the slurry with high content of solid wastes (80%), which play an important role in the formation of pores during the direct foaming process. The addition of E51 had great influence on the porous properties of geopolymer composites, which in turn affected their compressive strength (0.19–1.44 MPa) and thermal conductivity (0.09–0.12 W/mK). The addition of E51 enabled the production of geopolymer composites in a rather large range of total porosity (67.3–81.1 vol%), with an optimal sample possessing a total porosity of up to 78.7 vol%, a thermal conductivity of 0.086 W/mK, and a compression strength of 0.47 MPa. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the effect of the retarders urea and sodium phosphate on the hydration process and leaching of Cr(VI) in calcium sulfoaluminate cement from solid waste (WCSA). We investigated the mechanical properties and hydration processes of WCSA with varying urea and sodium tripolyphosphate contents using thermogravimetry coupled with differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM); the leaching behavior of the heavy metal Cr(VI) in the cement was analyzed using inductive coupled plasma emission spectrometry (ICP). The experimental results showed that lower urea or sodium tripolyphosphate (STPP) contents (0.2%) improved the compressive strength of cement specimens by 18.31% or 3.125% at 28 days, respectively. After incorporating STPP and urea, the hydration heat flow and total hydration heat of WCSA decreased. The porosity first decreased and then increased with increased STPP and urea content. The involvement of urea in hydration produced carbonate, which destroyed the structure of ettringite and formed a new calcium carbonate phase, leading to the release of Cr(VI). In the presence of STPP, a three-dimensional network structure of hydroxyapatite was generated. Chromium ions entered the three-dimensional network structure of hydroxyapatite, increasing the solidification of Cr(VI) in WCSA. [ABSTRACT FROM AUTHOR]

Backfilling mine goafs can significantly advance the mining industry; however, few researchers have used geopolymers reinforced with polypropylene fibers as filling materials. In this study, the flexural properties of fiber-reinforced green composite cementitious matrix–cemented tailings were examined, and the evolution mechanism of the internal structural properties of the prepared composite materials was determined. For this purpose, three-point bending tests, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction were performed on composite samples with different blending ratios, and discrete-element numerical simulations were conducted using PFC3D particle flow simulation software. The obtained results revealed that the flexural strength and fracture properties of the studied samples increased with increasing NaOH content, decreased with increasing water-to-solid ratio, and first increased and then decreased with increasing fiber content. At a fiber content of 0.6%, the reinforcement effect reached a local optimum. The higher the NaOH content, the more efficiently fly ash and slag formed polymerization products in an alkaline environment, which contained tailing sand aggregate particles, increasing the compactness of the composite structure. The fibers in the composite material were distributed both as a single inlay and as a three-dimensional network structure to form an effective wrapping and supporting system, which further improved the flexural performance of the sample. The PFC3D simulation data were consistent with the results of three-point bending tests, illustrating the sample degradation process. The findings of this work can provide a theoretical basis for the development of fiber-reinforced green sand filling materials for mine replenishment. [ABSTRACT FROM AUTHOR]

The anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) has shown to be a viable alternative since it allows energy recovery in the form of methane and generates a residue (digestate) that can be applied effectively as a soil improver or fertiliser. The potential for methane production and the digestates' characteristics depend on the substrate characteristics and the process variables such as temperature, solids retention time, and organic load. This study dealt with OFMSW anaerobic digestion under different organic loading rates and temperatures and the characteristics of the resulting digestates. Three semi-continuous reactors were operated at 20, 35, and 55°C and fed daily with ground, fresh OFMSW from Mexico City. The inoculum was temperature-adapted UASB granular sludge. The main results indicate that the anaerobic digestion was adequate, as the pH values were slightly alkaline, which is sufficient for methanization, and the alkalinity was not a limiting factor. Potassium and PO4-P increased with the organic load, and Kjeldahl nitrogen decreased. At 20°C, total organic carbon (TOC) increased substantially with the organic load; at 35°C, it remained without significant changes; and at 55°C, TOC slightly decreased with the organic load. The C/N ratio changed accordingly to TOC variations. At 20°C, the residual biogas potential increased with the organic load; at 35 and 55°C, it decreased with increasing organic load; the residual biogas potential increased with residual fatty acids concentrations. To comply with international standards for agricultural use, the digestates need only dewatering and supplementing with PO4-P. [ABSTRACT FROM AUTHOR]

Rapid scio-economic expansion in Bhopal city, with population growth from 14.35 lakhs in 2001 to 26 lakhs in 2023— roughly twice as much—during this time. If we compare with solid waste generation (SWG) in present and expected increase in years 2001, 2023, and 2035, it is 500 t/d, 800 t/d, and 2735 t/d, respectively, which shows almost three times higher from present generation. This led to the problem of solid waste management due to limited availability resources. This paper gives correlation between development aspects based on life index such as physical quality of life Index and SWG. The present study quantifies the SWG of Bhopal city using the socio-economic data such as per capita income, gross domestic product, physical quality of life index, population, and SWG of Bhopal city that forecast the future status. Abovementioned socio-economical parameters were used for forecast model and for this, multiple linear regression analysis was used for study. Based on the study and after correlation with SWG, it is found that population is in highest correlation than gross domestic production at current price, per capita income at current price, and physical quality of life index, respectively. The high value of R2 is 0.99638 in the models which is near 1. This will help the urban municipal solid waste management bodies to effectively manage solid waste in a sustainable manner. [ABSTRACT FROM AUTHOR]

In China, large amounts of industrial byproduct gypsum (IBG) end up as waste and excessive stockpiling due to its low whiteness and high impurity content. In this study, two typical IBG including phosphogypsum (PG) and flue gas desulfurization gypsum (FGDG) were the research object. The impurities removal and the whiteness improvement by the tandem pyro-hydro process were investigated. Species of impurities, mechanism of whiteness improvement and the evolution of the gypsum phase during the tandem process were revealed. The results indicate that the impurities responsible for the poor whiteness of IBG included organic matter, carbon particles, and silicates. The temperature of the pyro process is the critical factor. The IBG is calcinated at 400–500 °C to fully remove organic matter and carbon particles, while decompose silicates to silica. Following, in the hydro step, the calcined IBG was treated with dilute sulfuric acid (0.2–1.0 M) to remove ion impurities such as Fe(III), the higher temperature and higher acidity are favorable to the production of valuable CaSO4. After treatment, the whiteness of IBG was improved from below 40% to above 80%, and the soluble impurity content can meet the standards. Moreover, both PG and FGDG products exhibited a compressive strength exceeding 10.0 MPa of curing for 7 d. This work provides theoretical guidance to promote the resource utilization of IBG, especially as plastering materials after purification and whitening. [ABSTRACT FROM AUTHOR]

This article contributes to research in Political Corporate Social Responsibility (PCSR) by developing the idea of "political corporate social irresponsibility" (PCSiR). PCSiR occurs when corporations provide what are expected to be public goods but, in so doing, create or exacerbate public problems and diminish social welfare. We examine PCSiR through the case of a "garbage mountain" located near Tripoli City, Lebanon. This accumulation of solid waste is a potent symbol of the corporate failure in delivering contracted social services. We question how and to what extent has the power and influence of political actors in Lebanon hindered environmental protection and sustainable business practices. In response, we investigate the relations between corporations, the state and civil society that led to the garbage mountain and corporate response to political activism. Drawing on a neo-Gramscian approach to PCSR, we show how an interplay of consent and coercion fosters effective PCSiR, shielding those in power from responsibility for their self-serving behavior. [ABSTRACT FROM AUTHOR]

The extensive accumulation of coal-derived solid wastes in China has become a significant environmental challenge. Utilizing these wastes as resources is considered an effective approach. This study investigated activation systems for coal gangue to determine the optimal dosage for incorporation into cementitious materials. The effects of types and dosages of admixtures on the mechanical properties were examined. The results showed that augmenting the coal gangue content within a certain range enhanced the compressive strength of the composite cementitious materials. However, exceeding 20 wt.% led to a decline in compressive strength. The addition of coal gangue led to an increase in porosity. Furthermore, the addition of 4% lime and 4% gypsum resulted in enhanced properties. The performance of the resultant optimal cementitious material surpasses that of P·O 32.5 cement, making it a viable replacement in construction sector and contributing to the realization of resource recycling and ecological civilization construction goals. [ABSTRACT FROM AUTHOR]

The utilization of calcium carbide residue (CCR) to activate solid wastes can effectively promote sustainable development. This paper explores adding sodium carbonate (Na2CO3) to CCR activators to improve the early reactivity of alkali-activated materials (AAMs) made from sewage sludge ash (SSA). The research focuses on the effects of Na2CO3 on setting, hardening, mechanical strength, and environmental benefits. The findings indicate that Na2CO3 can shorten the paste' hardening time and significantly enhance the early mechanical properties. The introduction of Na2CO3 accelerates the consumption of CCR during the early phases and facilitates the formation of C-(N)-A-S-H gels. Meanwhile, it can significantly reduce the porosity and refine the pore structure. When the dosage reaches 8%, the total intruded pore volume of the sample decreases to 0.15 mL/g. This activation method reduces energy consumption, CO2 emissions, and costs by 69%, 50%, and over 90%, respectively, making it an efficient, eco-friendly approach to AAM production. [ABSTRACT FROM AUTHOR]

Mineral carbonation is a promising CO2 sequestration strategy that can utilize industrial wastes to convert CO2 into high-value CaCO3. This review summarizes the advancements in CO2 mineralization using typical industrial wastes to prepare ultrafine CaCO3. This work surveys the mechanisms of CO2 mineralization using these wastes and its capacities to synthesize CaCO3, evaluates the effects of carbonation pathways and operating parameters on the preparation of CaCO3, analyzes the current industrial application status and economics of this technology. Due to the large amount of impurities in solid wastes, the purity of CaCO3 prepared by indirect methods is greater than that prepared by direct methods. Crystalline CaCO3 includes three polymorphs. The polymorph of CaCO3 synthesized by carbonation process is determined the combined effects of various factors. These parameters essentially impact the nucleation and growth of CaCO3 by altering the CO2 supersaturation in the reaction system and the surface energy of CaCO3 grains. Increasing the initial pH of the solution and the CO2 flow rate favors the formation of vaterite, but calcite is formed under excessively high pH. Vaterite formation is favored at lower temperatures and residence time. With increased temperature and prolonged residence time, it passes through aragonite metastable phase and eventually transforms into calcite. Moreover, polymorph modifiers can decrease the surface energy of CaCO3 grains, facilitating the synthesis of vaterite. However, the large-scale application of this technology still faces many problems, including high costs, high energy consumption, low calcium leaching rate, low carbonation efficiency, and low product yield. Therefore, it is necessary to investigate ways to accelerate carbonation, optimize operating parameters, develop cost-effective agents, and understand the kinetics of CaCO3 nucleation and crystallization to obtain products with specific crystal forms. Furthermore, more studies on life cycle assessment (LCA) should be conducted to fully confirm the feasibility of the developed technologies. [ABSTRACT FROM AUTHOR]

At the end of 2020, Talang Gulo Landfill Site 1 in Jambi City was officially closed due to overcapacity. Municipal solid waste disposal has shifted to the Talang Gulo site 2 with a life expectancy of ± 90 years based on the design plan. However, this is difficult to realize because segregation and composting are not optimal, so more than 90% of the waste transported to the final processing site (TPA) is in a landfill. Thus, landfill mining was executed to utilize excavated landfill waste as a material and energy. It was carried out at depths of 3, 5, and 7 meters with an estimated sample age of > 9 years. The mixed landfill samples contained 55.6-66.2% moisture content, 50.3-80.6% volatile content, 19.4-49.7% ash content, 2.6-4.2% fixed carbon, and 3.5-5.7 MJ/kg calorific value. Furthermore, the landfill waste was dried using the biodrying method, combining fresh and landfill waste in the pile composition. The ratio of landfill waste to the addition of fresh waste is 1:0 (control pile), 1:1, 1:2, 1:3, and 1:4. The drying method reduced moisture content of 9-29.1% with a lower calorific value of 5-6.8 MJ/kg. Based on statistical analysis, it is known that waste ratio has a significant effect on moisture content. Based on the weighting results, the optimum mixture ratio is 1:1 (pile 2). [ABSTRACT FROM AUTHOR]

The integration of biochar (BC) production from organic waste with ampicillin (AMP), an emerging pollutant, adsorption is a novel and promising treatment approach. In this study, peanut shells, coffee grounds, digestates, and oyster shells were used for BC production. Among these, the use of anaerobic digestate from food waste fermentation to produce extracts for antibiotic adsorption is relatively unexplored. The pyrolysis temperature was determined using thermogravimetric analysis (TGA) and the materials were characterized with BET, SEM, FTIR, and XRD. The TGA results indicate that PSB, CRB, and DSB underwent pyrolysis involving cellulose, hemicellulose, and lignin, whereas OSB underwent crystal formation. Characterization revealed that DSB has more functional groups, a superior mesoporous structure, appropriate O/C ratio, and trace amounts of calcite crystals, which are favorable for AMP adsorption. Adsorption experiments demonstrate that all four materials adhere to the Freundlich and Langmuir isotherm and Elovich kinetic models, indicating predominant physical adsorption, with some chemical adsorption also present. Thermodynamic studies demonstrate that BC is spontaneous during adsorption and is a heat-absorbing reaction. DSB exhibits the strongest AMP adsorption. A 53.81 mg g−1 adsorbance was obtained at a dosage of 150 mg, pH = 2, and 60 °C. This study introduces innovative approaches for managing waste types and provides data to support the selection of suitable solid wastes for the preparation of BC with excellent adsorption properties. Furthermore, it lays the groundwork for future studies aimed at enhancing the AMP treatment efficacy. Preparation and characterization of biochar and adsorption mechanism of ampicillin in water. [ABSTRACT FROM AUTHOR]

The primary objective of this investigation is to assess the potential reusability of aged, dumped waste found in landfills for its application as a bulk geomaterial. Owing to the inherent heterogeneity of municipal solid waste (MSW), comprehensively understanding its behaviour—be it physical, mechanical, or dynamic—presents a significant challenge. Laboratory-based studies serve as a pivotal means to gain insight into a material's behaviour before its practical implementation. The study focuses on examining the intricate strength characteristics of MSW fines (< 4.75 mm) and fiber-reinforced MSW fines (with varying fiber content ranging from 0 to 10%) using the bender element laboratory test. The bender element analysis facilitates the determination of shear wave velocity (Vs) values by measuring the disparity in time travel between transmitted and received waves. Comprehensive scrutiny encompasses the influence of diverse parameters, notably the excitation frequency of the wave (f), applied confining pressure (σc), relative compaction (Rc), fiber content (FC), and the saturation state. Notably, the study identified an optimal fiber content of 1% across different excitation frequencies and applied confining pressures, where Vs or normalized Gmax values exhibited higher levels. Furthermore, the study involved fitting a cubic polynomial model and devising a generalized equation that correlates the normalized small strain modulus with the normalized shear strength for fiber-reinforced MSW fines. This equation serves as a valuable tool in understanding and predicting the material behaviour concerning small strain modulus and shear strength in fiber-reinforced MSW fines. [ABSTRACT FROM AUTHOR]

The treatment and resource utilization of solid waste and wastewater are becoming increasingly important. In this study, we propose a method to synthesize sulfur quantum dots using coked sulfur paste as raw material, which produced sulfur quantum dots with good water solubility, good dispersibility and stable luminescence performance. The synthesized sulfur quantum dots were used as a fluorescent probe for sensitively detecting low concentrations of silver ions (Ag+) based on the principle of fluorescence quenching. The detection method has a wide detection range (0–160 μM) with the lowest limit of detection of 7.1 μM and no quenching effect in the presence of 11 common ions, thus enabling the highly selective detection of silver ions. Moreover, a new method for the recovery of silver involving the strong bonding between sulfur quantum dots and silver ions was developed, i.e., even a low concentration of silver ions (under 200 μM) in industrial wastewater was converted into silver sulfide (Ag2S) and silver sulfate (Ag2SO4) for recovery. Results show that the average recovery rate reached 99.03% in the aqueous environment in the presence of five types of hetero-ions, namely, Na+, K+, Ca2+, Mg2+ and Al3+, showing both high efficiency and selectivity. This investigation realized the resourceful utilization of coked sulfur paste and provides a new pathway for the detection and recovery of low concentrations of silver in industrial wastewater. [ABSTRACT FROM AUTHOR]

In this paper, poplar sawdust (PS), walnut shell (WS), sugarcane bagasse (SB), polyethylene (PE), and paper napkin (PN) were selected as typical organic solid waste for the study of steam (co-)gasification coupled with on-line analysis of H 2 -rich syngas. The carbon conversion efficiency of PE is only 10.8% and needs to be improved. The mixture of SB + PE exhibited the most pronounced positive synergies, with H 2 /CO reaching 2.40 without catalyst and the synergistic indices of 0.320, 0.298, and 0.226 for H 2 yield, syngas yield, and H 2 /CO, respectively, and these synergies were evident throughout the entire gasification process. The synergistic mechanism was analyzed through the interphase migration of alkali and alkaline earth metals and the morphological properties of the char. Compared with the co-gasification at 900 °C, the synergistic indices of the SB + PE co-gasification parameters at 800 °C were reduced to different degrees, and even the co-gasification at 700 °C showed a remarkable negative synergism. [Display omitted] • Steam co-gasification of various MSWs was carried out online for H 2 -rich syngas. • Co-gasification of SB + PE showed optimal synergy for both H 2 yield and H 2 /CO. • Synergistic mechanism was discussed in terms of AAEMs migration and char structure. • High temperatures of 800∼900 °C contributed to unleashing synergistic potentials. [ABSTRACT FROM AUTHOR]

Sorption-enhanced steam gasification (SESG) has the potential to increase hydrogen (H 2) yield and facilitate the utilization of municipal solid waste (MSW) resource. However, the application of SESG technology in MSW still has broad research space. Therefore, this study innovatively used simulated MSW for gasification experiments. The bi-functional catalysts were prepared by co-precipitation method. In the CO 2 cyclic adsorption test, Ni0.1CA3 exhibited the highest total adsorption capacity, with 75% of the initial adsorption capacity still preserved. In the SESG test, Ni0.1CA3 showed excellent catalytic performance and the H 2 yield reached 31.69 mmol/g MSW. In addition, Ni0.1CA3 also demonstrated good stability and low carbon deposition in the SESG cycles. This could be attributed to the synergistic effect of the well-structured surface, appropriate basic sites, and calcium aluminate skeleton in Ni0.1CA3. This study served as a reference for the production of high-purity H 2 through the gasification of MSW, aligning with the development direction of green finance policy. [Display omitted] • MSW gasification realized the resource utilization of solid waste. • Ni0.1CA3 retained 75% of initial capacity after 10 CO 2 adsorption cycles. • Ni0.1CA3 showed superior hydrogen production potential in SESG of MSW. • The highest H 2 gas concentration reached 80.76 vol%. • The highest H 2 yield reached 31.69 mmol/g MSW. [ABSTRACT FROM AUTHOR]

AbstractEggshell waste has proved to be one of the most valuable natural sources due to its considerable contributions to several research fields. Herein, calcium oxide derived from various kinds of eggshell wastes has been introduced using the calcination method at different temperatures. The prepared micro- or nano-particles of calcium oxide are also characterized by XRD, FE-SEM, TEM, BET, and FT-IR techniques to clarify their morphological and structural aspects completely. With mild basicity, this bio-derived catalyst has been applied to the green synthesis of chalcones via the Claisen − Schmidt condensation reaction. Ultimately, the reusability of the catalyst is examined to increase the catalyst economization. [ABSTRACT FROM AUTHOR]

The improper disposal of industrial wastes will cause environmental pollution and economic losses due to the loss of active ingredients. Solid waste silica fume and pyrolusite powder were used to synthesize quartz ceramic proppant by pelleting and sintering to replace natural quartz sand for unconventional oil and gas exploitation. The effects of pyrolusite powder content and sintering temperature on the apparent density, breakage ratio, and acid solubility of the proppant were thoroughly studied. The phase composition and microstructure of the proppant were characterized by X‐ray diffraction and scanning electron microscopy, respectively. The results revealed that the main crystal phase of the proppant prepared without pyrolusite was cristobalite, while that with pyrolusite was cristobalite and quartz, and the content of quartz phase increased gradually with increasing the pyrolusite content. The addition of pyrolusite remarkably increased the density and improved the performance of the proppant due to the resulting glass phase at high temperatures and the presence of andradite. As adding 20% pyrolusite, the apparent density of the proppant sintered at 900°C was 2.26 g/cm3, while the breakage ratio under 28 MPa closed pressure and acid solubility reached the minimum, 9.89% and 5.3%, respectively, meeting the industrial standard requirements. [ABSTRACT FROM AUTHOR]

High-quality development paths in important cities are blurry and lacking. In order to explore the important engine for Chengdu high-quality development, driving forces and obstacles recognition has emerged as a pivotal technological solution. Using the Chengdu in Sichuan province of China as a research area and quantitative data from 2010 to 2019, this study has used content mining to recognize urban high-quality development (UHQD) variables, and calculated variables' weights by entropy weight method, and explored driving forces and obstacles of UHQD by the technique for order preference by similarity to ideal solution (TOPSIS) method. The main findings are: (1) there are 36 UHQD variables; (2) Chengdu high-quality development overall level soars from 2017 to 2019, only with two negative growth rates in 2011, 2015; (3) There are 3 key driving force paths: (1) improving green development by volume of industrial wastewater discharged, comprehensively utilised ratio of industrial solid wastes, harmless treatment rate of domestic garbage; (2) stressing open development by total import and export/GDP, actual use of foreign capital, number of foreign tourists/total tourists; and (3) intensifying shared development by funds for urban residents under basic provision protection. (4) 3 clearing obstacles paths can also realize Chengdu high-quality development: (1) improving innovative development level by R&D internal outlay, patent authorisations, state high-level tech enterprises; (2) optimizing coordinated development level by the proportion of tertiary industry; (3) promoting shared development level by urban basic pension insurance. According to these findings, suggestions are put forward to promote Chengdu high-quality development from the perspective of policy implementation. [ABSTRACT FROM AUTHOR]

Introduction: The quality of municipal solid waste governance is a key public issue associated with environmental, social, and health concerns that still demands appropriate indicators to encompass different policy, management, and data availability settings worldwide. This study aimed to develop and apply a Municipal Solid Waste Governance Index (MSWGI) to support the monitoring and assessment of the ultimate factors that influence the performance of municipal solid waste (MSW) management in municipalities, incorporating particularities of Global South countries. Methods: The development of the MSWGI comprised two approaches: (1) the establishment of a general theoretical framework with the identification of dimensions for monitoring MSW governance and (2) the development and application of the index using Brazil as a study case. The latter was accomplished through five incremental steps: (i) data selection and data quality analysis, (ii) data normalization and definition of data scores, (iii) data weighting and aggregation through statistical and participatory methods, (iv) data classification and, finally, (v) visualization of the index and its dimensions. Based on a broad literature review, three dimensions were proposed as the framework of the MSWGI: (i) regulatory quality (e.g., laws), (ii) voice and accountability (e.g., access to information; existence and functioning of the municipal council for the environment), and (iii) government effectiveness (e.g., financial and human resources; execution of government programs). A case study was then carried out with the 5,570 Brazilian municipalities to showcase the application and relevance of the MSWGI in a Global South context. Results: Despite the high regulatory quality condition in Brazil, this was not reflected in the MSWGI. In general, most municipalities have high (31.4%) and very high (23.7%) regulatory quality, contrasting low voice and accountability (32.4%), and medium government effectiveness (27.8%), the latter associated with the low quality of public services performed in municipalities. The index was also negatively influenced by the precarious mechanisms and structure of social participation; high levels of informality in the recycling sector, and low completeness and consistency of databases. The MSWGI was associated with socioeconomic development, and its concept and dimensions captured the complexities associated with MSW management. Discussion: The index, and the approach behind it, can be used as an objective tool to improve databases and the enabling conditions to foster MSW governance and management, while also creating indicators to assess its progress, facing the policy implementation gaps that are common to Global South countries. Also, rather than presenting an index to be directly transposed and applied to other locations, the steps of a strategy for generating an MSWGI from existing data were outlined. In this sense, this study creates mechanisms to refine these indicators within data-deficient context, presenting strategies that can be broadly applied. [ABSTRACT FROM AUTHOR]

In this study, an aging asphalt mixture was regenerated by a waste-based rejuvenator and cemented by solid waste-based solidification materials (SSMs). A splitting test, wheel tracking test, and three-point bending test were conducted to evaluate the properties of the regenerated asphalt mixture (RAM). The results reveal that the properties of the asphalt mixture were not diminished or were moderately enhanced by the 30% substitution of RAP. With the substitution of RAP to 100%, the splitting tensile strength, dynamic stability, and splitting strength ratio were decreased by 13%, 15%, and 5%, respectively. With the 100% substitution of SSMs for cement, the compressive strength, dynamic stability, flexural strain, and splitting strength ratios of the RAM were increased by 40%, 32%%, 14%, and 8%, respectively. The lightweight components can be supplemented, and low-temperature deformation and interlayer flowability can be improved by the incorporation of the rejuvenator. The generation of hydrated calcium silicate and ettringite for SSMs is greater than those of cement. The massive generation of ettringite has been observed to increase the solid phase volume by 120%, which may facilitate a more complete filling of the remaining pores in the RAM due to water evaporation. The regeneration and cement on green and the high performance of the rejuvenator and the SSM markedly enhanced RAM performance. [ABSTRACT FROM AUTHOR]

Water scarcity is a critical issue worldwide. This study explores a novel method for addressing this issue by using ductile cast iron (DCI) solid waste as an adsorbent for phosphate ions, supporting the circular economy in water remediation. The solid waste was characterized using XRD, XRF, FTIR, and particle size distribution. Wastewater samples of different phosphate ion concentrations are prepared, and the solid waste is used as an adsorbent to adsorb phosphate ions using different adsorbent doses and process time. The removal percentage is attained through spectrophotometer analysis and experimental results are optimized to get the optimum conditions using Design Expert V13. The pseudo-second order (PSO) kinetics model and Langmuir isotherm were fitted with the experimental results with maximum adsorption capacity (qmax = 0.28 mg/g). The thermodynamic analysis indicated that this adsorption process was spontaneous based on the negative value of Gibbs free energy ^G). Additionally, the positive values of enthalpy ^H) indicated the endothermic nature of this adsorption system. It was able to reach the highest adsorption percentage of 98.9 (%) for phosphate ions from aqueous solutions using response surface methodology (RSM) with optimum conditions of 10 mg/L phosphate ion concentration, pH = 8, normal room temperature, 9 min adsorption, and 0.5 g/L adsorbent dosage. [ABSTRACT FROM AUTHOR]

Fly ash has emerged as a prominent solid waste in China, leading to various environmental concerns and posing a threat to the health of living organisms, including humans. To enhance the industrial applicability of this waste material, a novel approach has been proposed wherein sand is replaced with fly ash as the primary raw material for wall grouting of coal mine roadways. To address the issue of low compressive strength and to improve the properties of fly ash shotcrete materials, a method employing an alkali activator to stimulate the chemical activity of fly ash has been put forward. The long‐term effectiveness of the shotcrete material has been evaluated using compressive strength testing and scanning electron microscopy testing methods. The impact of replacing sand with fly ash on the compressive strength of shotcrete and the activation effect of sodium sulfate (Na2SO4), NaOH, and Na2SiO3 on fly ash shotcrete have been studied. The results indicate that the compressive strength of fly ash shotcrete shows optimal improvement when the content of Na2SO4 is 3%. The ideal ratio of cement to fly ash is 1:3. Therefore, incorporating an appropriate amount of alkaline activator could effectively address the compressive strength issues of fly ash shotcrete materials. [ABSTRACT FROM AUTHOR]

With the concept of carbon neutrality, the value‐added utilization of biomass materials and solid waste becomes a cutting‐edge topic. Cellulose nanofibrils (CNFs) receive much attention due to their excellent properties in terms of high aspect ratio, specific strength, and specific surface area, but their large‐scale preparation remains a great challenge. Herein, a facile aqueous solution method is proposed for the fabrication of CNFs through artificial stone waste (ASW)‐assisted supramolecular interfacial interactions for the full‐component utilization in cement mortar materials. The strong hydrogen bonding interaction between ASW and CNFs can effectively prevent the intramolecular hydrogen bonding of CNFs and agglomeration of ASW, while improving the stability of CNF/ASW suspensions. The resulting CNFs/ASW with active hydroxyl or carboxyl group can improve the flexural and compressive strength of cement (30.8% and 37.8% higher than that of pristine cement, respectively) by embedding into the defects of cement mortar and promoting the hydration process of cement. In this work, not only a new idea is provided for the large‐scale preparation of biomass nanomaterials, but also the full‐component value‐added utilization of biomass and solid waste in cement materials is opened up. [ABSTRACT FROM AUTHOR]

Evidence abounds to indicate the prevalence of indiscriminate disposal of household solid waste as a practice in Nigeria. This practice contributes to green crime and jeopardizes public health. Therefore, the focal point of several academic papers has been household solid waste management. The objective of the current study was to make a rapid review on practices that scholars have recommended for household members to take proper care of their waste made of paper, cellophane, plastic, metal and wooden material and the peculiarities of these recommended practices in Nigeria with implications for waste management practices in developing countries worldwide. The study adopted the systematic review method to explore findings in the available relevant studies that were published within the years 2017 and 2023 to depict the current situations of the study's subject matter in Nigeria. The current study sorted out these findings into themes. The review pinpointed several recommended practices such as zero-waste policy, waste minimization/reduction, and various disposal methods to manage the household solid waste and the major factors responsible for the setbacks these practices have faced. The review further highlighted gaps in existing studies which could form the basis for prospective studies on household solid waste management. [ABSTRACT FROM AUTHOR]

Backfilling is a promising measure for controlling surface subsidence in mined-out areas and disposing solid wastes from the mineral processing, there are increasing demands of enhanced toughness and anti-cracking properties of backfill materials to prolong the service life under the complex loads. In this study, polypropylene (PP) fibers were employed to improve performance of backfills, four-point bending and uniaxial compression tests were conducted to investigate the failure process and damage evolution of fiber-reinforced aeolian-sand backfill materials (FABs) using Digital Image Correlation (DIC) and Acoustic Emission (AE) techniques. The results show that the compressive strength tends to decrease with the increasing fiber volume fractions, while the four-point bending strength shows a tendency to increase initially and then decrease, and the optimum volume fraction of PP fiber is 0.6%. At the optimal fiber volume fraction, PP fibers with lengths of 3 mm and 9 mm resulted in a 65.25% and 81.62% increase in the four-point bending strength of FABs, respectively. As indicated by DIC measurements, PP fibers with a length of 9 mm were more effective in controlling the horizontal and vertical displacements of FABs under four-point bending loads than that of 3 mm, and the cracks developed more slowly at the same deflection. In addition, PP fibers with a length of 9 mm have stronger crack extension delay characteristics due to longer effective anchorage distance, as evidenced by more frequent acoustic emission ringing counts and higher cumulative ringing counts. The results of the study may provide a theoretical basis for the application of FABs materials in backfilling. [ABSTRACT FROM AUTHOR]

Background: Healthcare waste (HCW) poses a global hazard, particularly in developing country hospitals where mismanagement is common due to poor practices among staff. Training healthcare workers has shown promise in enhancing practices and behaviors. The aim of this study was to assessHCW management at Sahloul University Hospital (2019–2021) before and after training sessions. Methods: This study was conducted at Sahloul University in Sousse, Tunisia, spanned two years (2019–2021) and consisted of three distinct stages. Two audits of Healthcare Waste Management (HCWM) were conducted using a predetermined assessment framework derived from ANGED's guidelines, with an educational session separating the two audits. Results: In terms of sorting practicesthere was a substantial improvement in sorting practices following training. Specifically, the overall compliance rate for sorting sharps increased from 60.3 to 77.6% (p < 10 − 3), and for sorting soft and solid waste, it rose from 32.5 to 72.4% (p < 10 − 3) in 2021. Overall, resource indicators demonstrated improvement between 2019 and 2021, the compliance rate for the intra-service collection step increased from 31.3 to 58.2%. However, we observed persistent inadequacies in container and bag labeling, as well as challenges in tracing the time of healthcare waste collection. Conclusion: Training led to significant improvements in HCW management practices among healthcare workers, though some areas still need enhancement. [ABSTRACT FROM AUTHOR]

Sludge thickening is a fundamental stage of treatment. This study investigated the application, in continuous treatment, of polymeric bubbles produced with cationic polymer P2900 and cocamidopropyl betaine (CAPB), a zwitterionic surfactant. The proposed reagent combination aims to form aerated flakes, solid waste structures, and rapidly rising air bubbles, ideal for treatments in compact units. Using this combination, it was possible to achieve a total solids concentration of 45% with the modified bubbles and 25% with the conventional water treatment. This level of thickening occurred under the following operating conditions: initial total solids (TS) concentration of 10 g L−1, a flow rate of 5 L min−1, saturation pressure (psat) of 3 atm, and polymer dosage of 10 mg (gTS)−1. The suggested mechanism of action involves the adhesion of P2900 molecules to CAPB at the air/water interface, forming a lining on the bubble surface. Additionally, polymerized species form due to the residual aluminum (Al) in the sludge, which would occur during flocculation in the helical tubular flocculator (HTF), adsorbing the micelles and bubbles of CAPB. The critical micellar concentration (CMC) of CAPB was 0.26 mmol L−1. Polymeric bubble technology can provide an efficient and cost-effective approach to sludge thickening in continuous treatment. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) along with a survey on epidemiologic and oxidative potential studies was used for analysing the current evidence of the impact of airborne emissions from municipal solid waste incineration (MSWI) on human health. The correspondence among investigated health outcomes and pollutants was discussed based on the Chemical Abstract Service (CAS) and the International Agency for Research on Cancer (IARC). LCA indicated the ability of MSWI in avoiding human health impact, about − 2 × 10−4 DALY/tonne together with avoided emissions of particulate matter (PM) and resource depletion, about − 2.5 × 10−3 kg Sbeq/tonne and about − 0.11 kg PM2.5 eq/tonne, respectively. Positive emissions were detected for greenhouses (about 900 kg CO2eq/tonne) and ecotoxicity (about 15,000 CTUe/tonne). Epidemiologic studies performed on population exposed to MSWI reported quite contrasting results. In some of these, hazard ratio (HR) ranging from about 0.7 to 2.2 was reported concerning the incidence of stomach, liver, breast and bladder cancer. Larger agreement was detected concerning the incidence of larynx and lung cancer with HR ranging from about 1 to about 2.6. Direct causal nexuses were not definitively identified. Oxidative potential of PM was characterized by a high Pearson correlation > 0.8 to the presence of CrVI, Cu and Zn. These heavy metals were also identified by both CAS and IARC as toxic (i.e. Cu and Zn) and cancerous (i.e. CrVI) substances affecting the organs of both respiratory and digestive apparatus. In general, even if more research is necessary, LCA, oxidative potential and the epidemiologic survey results showed a high level of accordance. This suggests their integrated exploitation for supporting the investigation of both direct and indirect consequences on environment and health related to waste incineration for both retrospective and predictive studies. [ABSTRACT FROM AUTHOR]

The persistent reliance on coal has resulted in the accumulation of substantial coal gangue, a globally recognized problematic solid waste with environmental risks. Given the coal gangue properties and global land degradation severity, the resourceful utilization of coal gangue as soil conditioners is believed to be a universally applicable, cost-effective, high-demand and environment-friendly model with broad application prospect. The direct application of raw coal gangue faces challenges of low active beneficial ingredients, inadequate water and fertilizer retention, presence of potentially toxic elements, resulting in limited efficacy and environmental contamination. This paper provided a comprehensive review of various modification methods (including mechanical, chemical, microbiological, thermal, hydrothermal and composite modifications) employed to enhance the soil improvement performance and reduce the environmental pollution of coal gangue. Furthermore, an analysis was conducted on the potential application of modified coal gangue as a muti-function soil conditioner based on its altered properties. The modified coal gangue is anticipated to effectively enhance soil quality, exhibiting significant potential in mitigating carbon emissions and facilitating soil carbon sequestration. This paper provided innovative ideas for future research on the comprehensive treatment of coal gangue and restoration of degraded soil in order to achieve the dual goals of zero-coal gangue waste and sustainable agriculture. [ABSTRACT FROM AUTHOR]

AbstractThe escalating growth in municipal solid waste production underscores the imperative need for efficient waste management, especially given that a substantial portion of MSW comprises biodegradable materials suitable for composting. This study investigates the impacts of using a synthetic bulking agent (perforated plastic balls) in conjunction with biochar, a natural bulking agent, on the aerobic composting of kitchen waste. The study aim to evaluate the effectiveness of this combined approach in optimizing the composting process. Four trials, each spanning 30 days, were conducted to assess the effects of different combinations of synthetic and natural bulking agents. The study uses a uniform-size perforated synthetic bulking agent in combination with biochar to enhance the composting process. Results indicate that incorporating the perforated plastic balls (8% by weight) alongside biochar significantly influenced key composting parameters. This approach accelerated the initial rise in temperature to 55°C, enhanced the reduction of total organic carbon, improved total Kjeldahl nitrogen retention, and facilitated the achievement of optimal carbon-nitrogen (C/N) ratios ranging from 19 to 20. Furthermore, the analysis of phosphorus (P) and potassium (K) loss during composting revealed that potassium is more susceptible to leaching than phosphorus due to its higher mobility. The study concludes that the addition of a uniform-size perforated synthetic bulking agent, constituting 8% (by weight), in conjunction with a natural bulking agent, effectively enhances the composting process. [ABSTRACT FROM AUTHOR]

A large amount of arsenic-containing wastewater discharged by the non-ferrous metal industry will cause serious environmental problems if it is not properly treated. Pyrolysis char of waste tire is a kind of solid waste. Since the surface properties of tire derived char (TC) are affected by tar/ash adhesion during pyrolysis, it is necessary to modify TC to treat wastewater containing As(V) effectively as an adsorbent. At present, most studies on the modification of TC are prepared into activated carbon by high temperature activation in N2 atmosphere. In this study, TC was modified at room temperature and air atmosphere, and Fe(OH)3-TCNaOH adsorbent with particle size of 61–75 μm was obtained under the premise of the removal rate of As(V) and the settling performance of the adsorbent. When the initial concentration of As(V) was 5 mg/L, the removal rate of As(V) by Fe(OH)3-TCNaOH with a particle size of 61–75 μm could reach 90% within 30 min under a wide pH range (3–9). The adsorption of As(V) by Fe(OH)3-TCNaOH was most affected by the coexistence of PO43-, which resulted in the removal rate of As(V) decreased by about 20%. The adsorption mechanism shows that the significant increase in the number of 3–5 nm mesoporous pores of Fe(OH)3-TCNaOH and the formation of H bonds are beneficial to the adsorption of Fe(OH)3-TCNaOH to As(V), and improve the stability of Fe-As complex. [ABSTRACT FROM AUTHOR]

Improper solid waste management in urban and semi-urban areas has led to adverse impacts on the environment, public health, and the economic well-being of communities. Therefore, this study analyzes the status of household solid waste management practices and their effects in Logia Town, Afar, Ethiopia. To achieve this objective, the study utilizes both descriptive and econometric models (binary logistic regression model). The descriptive results of the study revealed that there is general awareness of the importance of solid waste management (SWM) and its impact on the environment, economy, and human health among the respondents. Regarding respondents' attitudes, the majority of households understand the responsibility of proper waste disposal and its impact. However, in terms of solid waste management practices, 80% of households do not properly segregate their waste, 59.3% do not separate solid waste (SW) before disposal, and 74% of households engage in improper disposal practices. About 95.9% of respondents were aware that improper waste management can lead to diseases such as diarrhea, typhoid, and cholera. Around 65% of the sampled households considered solid waste as a source of wealth, and, as a result, 56% of them reuse, recycle, and reduce waste. This indicates that solid waste has economic value for society. Regarding the environmental impact of SW, about 89% of respondents argued that SW adversely affects the environment by polluting rivers, lakes, wells, and air. This environmental impact negatively affects the well-being and economic status of the community. The binary logistic regression model found that having adequate solid waste landfills, access to door-to-door solid waste collection, knowledge of SWM rules and regulations, treating waste as a resource, and understanding the 3Rs (recycle, reuse, reduce) had positive and significant effects on the adoption of proper solid waste management practices in the study area. Therefore, to reduce undesirable effects and improve the value of SW, the relevant authorities should provide adequate solid waste landfills and door-to-door collection services, create awareness about SWM rules and regulations, and promote knowledge of the 3Rs. Article highlights: Most residents in Logia Town, Afar, have poor waste management habits, with many dumping waste improperly. Awareness of solid waste issues is high, but recycling and reusing practices are underutilized. Households with better waste facilities and services, or who view waste as a resource, manage waste more effectively. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) is incinerated to reduce the volume and recover energy and materials. The generation of MSW has been increasing over the past few decades due to the increase in population and changing consumption habits. Rising environmental and economic concerns have increased the importance of waste treatment and recovery. Currently, MSW may take three alternate or parallel routes: direct recycling, incineration, or landfill, depending on the country and location. MSW incineration has three products in addition to energy: bottom ash, fly ash, and off-gas. After incineration, bottom ash usually still contains many materials to be recovered, such as glass, ceramics, and metals with a degree of oxidation. This study focuses on aluminium recovery from MSW incineration bottom ash from two different countries. The 2–30 mm fraction of aluminium particles was characterized in terms of its size, shape, and oxide thickness, and its effects on aluminium recovery were investigated. In addition, the ability of mechanical pre-treatment to remove oxides prior to melting was studied. The results were compared with the analytical modeling developed in this study. An increasing particle size and surface area resulted in an increase in aluminium recovery. Mechanical pre-treatment increased the yield for smaller particles to a larger extent than larger particles due to the difference in the oxide/metal ratio. [ABSTRACT FROM AUTHOR]

Cruise-type aquaculture on deep-sea aquaculture vessels is an important direction for developing of modern marine fisheries. The article explored the effect of transverse rolling motion on the flow field characteristics in the tank based on FLOW-3D software, and calculated the removal of waste particles in the flow field under different transverse rolling conditions on this basis. The results showed that when controlling the period of transverse rolling, the flow velocity in the aquaculture tank increased slightly as the amplitude of the transverse rolling angle increased from 0° to 2°. When the amplitude of the transverse rolling angle was increased from 2° to 7º, the flow velocity in the aquaculture tank showed a large increase, and the v50% increased from 0.171 m/s to 0.477 m/s; the increase of the transverse rolling angle also made the overall distribution of the flow velocity more discrete. The flow uniformity index of the conditions with the transverse rolling angle amplitude of 2° or less is mainly concentrated in 0.8-0.85, while when the transverse rolling angle amplitude is increased to 3º, the flow uniformity of the aquaculture tank decreases significantly. The flow uniformity indices of the water in the aquaculture tank are all less than 0. 8. When the amplitude of the transverse rolling angle is certain, the transverse rolling period is shortened, the flow velocity in the aquaculture tank increases sharply, and the v50% of the flow velocity of each condition and the other quartiles show a linear growth trend while the uniformity of the flow of the water in the tank does not change significantly. For the removal of waste solid particles in the aquaculture tank, the whole process is divided into two phases with opposite effects when the period of transverse rolling and the properties of particles themselves are certain. From the time when the particles were released into the flow field to the 1000 s after the release, the smaller the amplitude of the transverse rolling angle was, the higher the removal rate was; thereafter, until the end of the calculation of the whole example, the larger the transverse rolling angle was, the higher the removal rate of the particles was. The period of transverse rolling did not effect the removal of particles in the aquaculture tanks, and the time to reach the standard for particles removal was very close for each condition. [ABSTRACT FROM AUTHOR]

The solid waste and waste acid generated during the production of titanium dioxide contain considerable amount of scandium, which are valuable secondary resources. In this study, the titanium dioxide waste acid was used to leach the scandium-containing solid waste, and the leached solution was pretreated for iron removal by reduction-crystallization process. After that, scandium was recovered from the leached solution by using the P204-TBP co-extraction system. The process parameters were investigated systematically. The results showed that iron powder reduction-crystallization for iron removal at molar ratio of Fe:Fe3+ = 0.25 was most suitable for subsequent extraction, and the scandium extraction efficiency could reach 100% using 15% P204-5% TBP at 25 °C with A/O = 8. This study provided a novel process for treating scandium-bearing solid waste with scandium-bearing waste acid, showing great potential for industrial application. [ABSTRACT FROM AUTHOR]

Spent carbon cathode (SCC) is one of the major hazardous solid wastes generated during the overhaul of electrolysis cells in the aluminum production process. SCC is not only rich in carbon resources but also contains soluble fluoride and cyanide, which gives it both recycling value and significant leaching toxicity. In this study, we explore the properties, emissions, and disposal strategies for SCC. Pyrometallurgy involves processes such as vacuum distillation, molten salt roasting, and high-temperature roasting. Hydrometallurgy describes various methods used to separate valuable components from leachate and prepare products. Collaborative disposal plays a positive role in treating SCC alongside other solid wastes. High-value utilization provides an approach to make full use of high-purity carbon-based materials. Finally, we analyze and summarize future prospects for the disposal of SCC. This study aims to contribute to the large-scale treatment and resource utilization of SCC while promoting circular economy principles and green development initiatives. [ABSTRACT FROM AUTHOR]

Phosphogypsum is a common industrial solid waste that faces the challenges of high stockpiling and low utilization rates. This study focuses on the mechanical properties and internal characteristics of cementitious materials with a high phosphogypsum content. Specifically, we examined the effects of varying amounts of ground granulated blast furnace slag (5–28%), fly ash (5–20%), and hydrated lime (0.5–2%) on the stress–strain curve, unconfined uniaxial compressive strength, and elastic modulus (E50) of these materials. The test results indicate that increasing the ground granulated blast furnace slag content can significantly enhance the mechanical properties of phosphogypsum-based cementitious materials. Additionally, increasing the fly ash content can have a similar beneficial effect with an appropriate amount of hydrated lime. Furthermore, microscopic analysis of the cementitious materials using a scanning electron microscope revealed that the high sulfate content in phosphogypsum leads to the formation of calcium aluminate as the main product. Concurrently, a continuous reaction of the raw materials contributes to the strength development of the cementitious materials over time. The results could provide a novel method for improving the reusing phosphogypsum amount in civil engineering materials. [ABSTRACT FROM AUTHOR]

A green, low-carbon concrete is a top way to recycle waste in construction. This study uses industrial solid waste slag powder (S95) and fly ash (FA) as binders to completely replace cement. This study used recycled coarse aggregate (RCA) instead of natural coarse aggregate (NCA). This is to prepare alkali-activated recycled concrete (AARC) with different cementitious material systems. Alkali-activated concrete (AAC) mixtures are modified for strength and performance based on the mechanical qualities and durability of AARC. Also, the time-varying effects of the environment on AARC properties are explored. The results show that with the performance enhancement of RCA, the mechanical performance of AARC is significantly improved. As RCA's quality improves, so does AARC's compressive strength. At a cementitious material content of 550 kg/m3, AARC's 28d compressive strengths using I-, II-, and III-class RCA were reduced by 2.2%, 12.7%, and 21.8%, respectively. I-class AARC has characteristics similar to natural aggregate concrete (NAC) in terms of shrinkage, resistance to chloride penetration, carbonization, and frost resistance. AARC is a new type of green building material that uses industrial solid waste to prepare alkali-activated cementitious materials. It can effectively reduce the amount of cement and alleviate energy consumption. This is conducive to the reuse of resources, environmental protection, and sustainable development. [ABSTRACT FROM AUTHOR]

This study examines the strategic incorporation of various recycled materials into asphalt concrete, specifically focusing on municipal solid waste incineration bottom ash (MSWI BA), recycled asphalt shingle (RAS), and recycled concrete aggregate (RCA). Due to the high porosity of MSWI BA and RCA, and the significant asphalt binder content (30–40%) found in RAS, there is a need to increase the amount of liquid asphalt used. RAS is posited as an efficient substitute for the asphalt binder, helping to counterbalance the high absorption characteristics of MSWI BA and RCA. The research objective is to quantitatively evaluate the effect of the combined use of RAS, MSWI BA, and RCA in Hot Mix Asphalt (HMA). This study encompasses several laboratory evaluations (i.e., rutting and tensile strength tests) and a cost–benefit analysis, which is a life cycle cost analysis. The results indicate that the combined use of these materials results in a higher tensile strength and rut resistance when compared with the control (with virgin aggregate). According to the cost–benefit analysis result, when the three recycled materials are used for an HMA overlay over an existing aged pavement, it could be 60–80% more cost-effective compared to a conventional HMA overlay, thereby offering significant economical savings each year in the field of road construction. [ABSTRACT FROM AUTHOR]

Solid wastes have been widely used as a cement substitute in precast concrete. On the one hand, solid waste can effectively ameliorate a series of problems caused by steam curing. On the other hand, the use of solid waste can reduce the amount of cement used in the construction industry and reduce carbon emissions. However, due to the complexity of the steam curing system, the performance of precast concrete prepared under different steam curing conditions varies greatly. Moreover, there are a wide variety of solid wastes, and the differences in the physicochemical properties of different solid wastes are significant. Therefore, it is necessary to systematically determine the mechanism of action of commonly used solid wastes. In this paper, the steam curing system is introduced in detail, and the mechanism of action of solid waste in precast concrete is systematically summarized. It was found that an appropriate increase in the temperature and duration of steam curing facilitates the strength development of precast concrete. In addition, there is a difference in the effect of the addition of solid wastes on the early and late strength of precast concrete, which usually leads to a decrease in the demolding strength of precast concrete, but increases the late strength of precast concrete. This study provides a reference for rationally regulating steam curing systems and realizing the comprehensive utilization of solid wastes in precast concrete. [ABSTRACT FROM AUTHOR]