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Dry anaerobic digestion (dry-AD) is an attractive process for solid wastes such as agri-food waste. However, some limitations mainly associated to lack of effective mixing, can hinder the methane production capacity of the systems. Bulking agent (BA) has been proposed as a solution to the compaction issues in systems without mechanical agitation, such as leaching bed reactors. However, effects of BA are still not clear, and, thus, the factors to consider for its dose has not been optimized yet. This work studies the effect of BA in dry-AD. Two substrates with different characteristics were proposed as models, bean peel as a lignocellulosic substrate and a mixture of food waste as a readily biodegradable substrate. Inert plastic rings were used as BA at different BA:S ratios. Assessed BA:S ratio did not affect the performance of methane production for the lignocellulosic waste, but it did significantly affect to the easily biodegradable substrate, showing up to a 28% of methane production increase. This result could be due to the presence of lignocellulosic compounds in the bean peel, behaving like a natural BA. In assays with an increased bed height, the compaction of the system was more severe, resulting in the rapid acidification of the processes. At these conditions, the positive effect of BA addition was more marked, allowing methane production and no acidification of the system. Thus, the addition of BA is a suitable strategy for improving methane production or stability in dry-AD systems without requiring the stirring of the systems. • Bulking agent (BA) addition is assessed as alternative to stirring in dry AD. • Positive effects by BA was due to an increase of the porosity in the digester bed. • Optimal BA:S ratio was strongly dependent on the characteristics of the substrate. • Low lignocellulosic content substrates were more favoured by BA addition. • BA addition was able to avoid acidification by enhancing the methanogenic activity. [ABSTRACT FROM AUTHOR]

As one of the main waste streams of the manufacturing process of solid oxide cells (SOCs), scrap half-cells - discarded before the deposition of the barrier layer and the air electrode - imply the loss of significant quantities of ceramic composite material containing critical and hazardous elements, namely yttria-stabilized zirconia (YSZ) and NiO. These materials represent more than 90 wt% of an entire anode-supported cell. In this contribution, scrap half-cells were fragmented and subjected to three subsequent milling and sieving (below 25 μm) steps to recover composite NiO-YSZ powders with the appropriate specifications for reuse in SOC manufacturing. The overall characterization in terms of specific surface area, particle size distribution and crystalline phase retention confirmed the suitability of the recovered powders. Half-cells were manufactured including 30 wt% of recovered NiO-YSZ composite powders in their fuel electrode support, produced via tape-casting in combination with 70 wt% of virgin materials. The obtained cells were morphologically, mechanically and electrochemically tested and compared against standard cells constituted by 100 wt% of virgin materials. The electrochemical characterization highlighted 0.68 A cm−2 for the standard and recycled cells, at 600 °C and 0.7 V, while at 650 °C and same voltage both cells measured 1.12 A cm−2. This demonstrates the feasibility of recovering scrap SOCs through the presented method. [ABSTRACT FROM AUTHOR]

In order to realize the resource utilization of solid waste and the treatment of phenol wastewater in China, a new porous ceramic granules (PCG) with the function of degrading phenol wastewater was prepared by using titanium-containing blast furnace slag, iron tailings and fly ash as raw materials, which realized the sustainable development of "treating waste with waste". The effects of different pore forming agents on the structure, morphology, ionic state of PCG samples and the adsorption behavior of phenol in aqueous solution were investigated. The results show that the change of pore forming agent has no obvious change on the crystal structure. When carbon powder (CP) and starch (SH) are used as pore forming agents, the internal pore structure is relatively dense and less porous, and it is not easy to form liquid channels. When ammonia bicarbonate (NH) is used as pore-forming agents, the internal pore structure is very developed and has many three-dimensional pore structures. Under the conditions of PH 2, phenol concentration 10 mg/L and solid-liquid ratio 3 g/L, TOC removal rates of CP-PCG, SH-PCG and NH-PCG samples after 72 h adsorption reaction were 39.10 %, 14.00 % and 93.29 %, respectively. In addition, the surface functional groups, hydrogen bonds and π-π interactions of PCG samples may be involved in the adsorption of phenol. This work not only provides a low-cost, environmentally friendly and simple technology for phenol-containing wastewater treatment, but also provides a new idea for the effective use of solid waste resources. [ABSTRACT FROM AUTHOR]

Aluminum electrolysis spent cathode carbon (SCC), as typical solid hazardous waste, poses significant environmental risks. Harmless treatment of SCC and recycling of its carbon component are important research areas. In this study, SCC was subjected to microwave hydrothermal acid leaching to remove harmful components, followed by the production of high-quality graphite via iron-catalyzed graphitization. The effects of reaction temperature, heating time, and catalyst loading on the graphitization conversion of SCC were investigated. The catalytic graphitization process of SCC was optimized using the response surface method. The results show that when the reaction temperature is 1520 °C, the heating time is 85.24 min, and the catalyst loading is 46.15 wt%, the graphitization degree of the sample is 97.61 %. The samples prepared under the optimal conditions were characterized using XRD, Raman, SEM, and TEM. The results reveal that the catalytic graphitization process significantly influences the conversion of microcrystalline structures in SCC into graphite structures. The iron-catalyzed transformation of microcrystalline carbon was analyzed to elucidate the graphitization transformation mechanism. This study offers an effective pathway for the high-value utilization of SCC. It also serves as a technical reference for the catalytic graphitization conversion of carbon materials. [ABSTRACT FROM AUTHOR]

• Critical application of the Waste Flow Diagram methodology in Tuy Hoa city, Vietnam. • Plastic leakage into the aquatic environment from 0.8 to 2.7 kg/cap/year. • The SWM collection system is the main contributor to plastic leakages. Plastic mismanagement and its subsequent pollution by rapid economic development and urbanisation pose significant challenges for modern world society. Notwithstanding one of the main sources for macro plastic leakage into the ocean from land, precise assessment of plastic pollution origins from Southeast Asia is yet to be clearly examined. In order to make informed decisions and prioritise areas of improvement it is required to better understand the waste leakage dynamics at the local level. In this work, the Waste Flow Diagram (WFD) was applied to understand the sources and fates of plastics leaking from the solid waste management system for the case of Tuy Hoa City, Phu Yen, Vietnam. The study shows scenarios of leakage into the aquatic environment ranging from 0.8 to 2.7 kg/cap/year, which originates mainly from the collection system. Targeted improvements to this stage of the service could reduce leakages and the overall environmental impacts of mismanaged plastic waste. The results of this study show the necessity and importance of having up to date and reliable data to better inform stakeholders and service planning, facilitating efficient action against plastic pollution. As the first peer-reviewed scientific article critically applying the WFD, this work highlights the steps and challenges of the methodology and critically analyses different methodological pathways. [ABSTRACT FROM AUTHOR]

• Monitored microbial shifts during anaerobic degradation of two types of food waste. • Sampling of both leachate and solids revealed microbial composition differences. • Substrates led to different population dynamics and methanogenic pathways. A key question in anaerobic microbial ecology is how microbial communities develop over different stages of waste decomposition and whether these changes are specific to waste types. We destructively sampled over time 26 replicate bioreactors cultivated on fruit/vegetable waste (FVW) and meat waste (MW) based on pre-defined waste components and composition. To characterize community shifts, we examined 16S rRNA genes from both the leachate and solid fractions of the waste. Waste decomposition occurred faster in FVW than MW, as accumulation of ammonia in MW reactors led to inhibition of methanogenesis. We identified population succession during different stages of waste decomposition and linked specific populations to different waste types. Community analyses revealed underrepresentation of methanogens in the leachate fractions, emphasizing the importance of consistent and representative sampling when characterizing microbial communities in solid waste. [ABSTRACT FROM AUTHOR]

• Estimates of modeled CH 4 emission (E) data for 1,325 U.S. landfills were reviewed. • Operators use two methods to estimate E from landfills with a gas collection system. • First-order decay (FOD) method shows increasing emissions. • Collection efficiency assumption method shows decreasing emissions. • FOD method shows some agreement to remotely sensed national estimates. As part of its commitment to the United Nations Framework Convention on Climate Change, the U.S. annually develops a national estimate of methane emissions from municipal solid waste (MSW) landfills by aggregating activity data from each facility. Since 2010, the U.S. has reported a 20 % decrease in MSW landfill emissions despite a 21 % increase in tons disposed. Operator-submitted data were investigated to understand the causes of this decline. In the U.S., operators of landfills with a gas collection and control system (GCCS) calculate their facility's emissions via two separate approaches – (1) first-order decay (FOD) and (2) collection efficiency assumption (CEA) − and select either result to feed into the annual inventory. The FOD model predicts methane generation proportional to waste disposal and that approach calculated a 19 % increase in total methane generated from 2010 to 2022, whereas generation via the CEA approach decreased by 8.9 %. The amount of measured methane collected has increased 7.5 % for the same years. Discrepancies between the two models' generated methane, assumed gas collection efficiencies, and oxidized methane compound into substantive differences in national estimates. Operators more frequently select the CEA method, which results in decreased national estimates. If only the FOD method was used, U.S. MSW landfill emissions would be 1.3-1.7 times greater than current estimates which is similar to recent extrapolations from remote sensing campaigns in the U.S. Both models contain parameters with large inherent uncertainty. Without measurement methods that continuously quantify both point-source and diffuse emissions, an assessment of either equation's accuracy cannot be made. [ABSTRACT FROM AUTHOR]

Steel slag (SS) as solid waste, has low resource utilization efficiency and seriously endangers environmental safety and human health. To explore the potential utilization value of SS and address the flammability challenge of rigid polyurethane foam (RPUF), with a novel flame‐retardant system composed by SS and dimethyl methyl phosphonate (DMMP) was explored. The DMMP/SS system effectively improved the high temperature stability of the RPUF composites. When the mass ratio of SS and DMMP was 1:1, the limiting oxygen index of RPUF/DMMP/SS reached 23.1 vol% and UL‐94 vertical combustion tests passed V‐2 level. Upon incorporation of 15 wt% DMMP, the initial decomposition temperature (T−5 wt%) reduced to 165.3°C, a decrease of 32.2%, while the Tmax2 and residue yield at 700°C exhibited negligible alteration. The peak heat release rate of RPUF/DMMP/SS composite (118.20 W g−1) was 11.02% lower than that of pure RPUF, indicating the significant enhancement of fire safety of the composites. Results confirmed that a synergistic flame‐retardant mechanism was existed between DMMP and SS in enhancing the fire safety of RPUF composite. Introducing a 20 wt% SS content reduces the ID/IG ratio to 1.85, thereby markedly enhancing its heat resistance. This work provides a new application field of SS and paves a novel approach to enhance fire safety of polymers. [ABSTRACT FROM AUTHOR]

Landfilled solid waste polymers were converted into high octane green fuels and hydrocarbons by a catalytic depolymerization process. Experiments were conducted in a batch catalytic reactor pressurized with methane as a co-feed. Design of Experiments (DOE) methodology was used for process optimization and parametric study. The operating conditions that maximize the liquids aromatic hydrocarbons were found using response optimizer tool. The reaction temperature and polymer to catalyst ratio (PCR) were found to have significant effects on the responses and methane pressure was not significant for yields of solids, liquids and gaseous products. However, pressurized methane facilitated dehydrocyclization reactions resulting in increased monoaromatic hydrocarbons in the final liquid products. Experiments conducted with methane feed at optimized reaction conditions resulted in 89% aromatic hydrocarbons, 8% paraffins and about 3% other hydrocarbons in liquid products. Aromatic products included benzene (6.5%), toluene (25%), xylenes (27%), ethylbenzene (4.5%), other monoaromatics (22%) and polyaromatic hydrocarbons (4%). Gaseous products contained propylene (47%) and hydrogen (23.9%). The utilization of waste polymers as feedstock materials, flare gas (methane) as a co-feed, and zeolite catalysts makes this batch zeolitic slurry process greener, resulting in green hydrocarbons and green fuels. [ABSTRACT FROM AUTHOR]

This work reports the degradation of cellulosic material, i.e., paper, under different environmental conditions (soil and hydrolytic). Models were developed using central composite design (CCD) within the framework of response surface methodology (RSM) and artificial neural network (ANN) techniques. It is done as part of a solid waste management system to eliminate the waste produced by excessive paper usage and obtain optimized degradation conditions of paper. In view of the real environments where paper-based solid wastes are usually exposed, soil degradation and hydrolytic degradation of paper were investigated. The factors pH (4–10), compost ratio (2–5), CaCl2 (5–15 ppm), and time (7–20 days) were independent factors that varied for the study, and degradation conversion was measured as the dependent variable for soil degradation of paper. The factors pH (4–10), CaCl2 (2–5 ppm), tripotassium phosphate (TPP, 2–5 ppm), and time (6–16 days) were independent variables that varied for the study, and degradation conversion was the dependent variable for hydrolytic degradation of paper. The optimal conditions for soil degradation were determined to be a pH of 4, a compost ratio of 5, a salt (CaCl2) addition of 5 ppm, and a duration of 20 days, resulting in the highest observed conversion rate. The coefficient of regression (R2) for CCD is 87.24%, whereas it is 94.82% for ANN. The optimal conditions for achieving maximum conversion in hydrolytic degradation include a pH of 10, a CaCl2 salt concentration of 5 ppm, a TPP salt concentration of 2 ppm, and a duration of 16 days. The coefficient of regression for CCD is 75.15%, while the coefficient of regression for ANN is 93.91%. In both deterioration scenarios, the data exhibited a higher degree of fit when modeled using ANN compared to CCD (RSM). [ABSTRACT FROM AUTHOR]

The mechanical behaviour of Fibre-reinforced sands (FRS) has been extensively studied, presenting improved mechanical properties compared to unreinforced soils. Many models have been developed to predict its general stress-strain behaviour. However, the use of double-phase models in FRS is still incipient. Double-phase models are advantageous because they can simulate the whole FRS and the behaviour of its individual components, soil skeleton and reinforcement. This paper uses a modified model for Municipal Solid Waste to reproduce the FRS mechanical response. Introducing a new hardening parameter and a dilatant zone allowed the model to reproduce FRS dilatancy. The model's variables are easily understood, allowing the reproduction of the mechanical behaviour of FRS formed by sands with void ratios ranging from 0.610 to 0.917 and mean grain size from 0.29 to 0.83 mm. The fibres' lengths varied from 12.5 to 51 mm. The results of triaxial and hollow cylinder torsional tests under different stress paths had their main characteristics (peak strength, post-peak behaviour, dilatancy and reinforcement effectiveness) well captured by the model. Predicted and experimental FRS's deviator stress usually differ by less than 15% and the model performance is equivalent or superior to other available models, even requiring fewer input parameters. [ABSTRACT FROM AUTHOR]

One of the most important problems and the main obstacle of this process is the transformation of the complex structure of lignocellulose. One of the ways to break the lignocellulosic structure is to use suitable pretreatment compounds and nanoparticles with appropriate concentration. For this purpose, the synergistic effect of 6%NaOH pretreatment with different magnetite nanoparticle (MNP) concentrations was assessed for maximizing the biogas production. In this study, the optimal mixing ratio of MSW and SS codigestion was determined from our previous studies (MSW:SS 60:40). Application of the 6%NaOH pretreatment alone increased biogas and methane production by 24.6 and 35.4%, respectively, compared to the control. Also, the 6%NaOH pretreatment alone elevated cellulose by 85% while reducing lignin and hemicellulose by 64 and 33%, respectively. The greatest biogas and methane production was obtained in the reactor of 6%NaOH with an MNP concentration of 110 ppm, experiencing an 86 and 162% increase compared to the control. The greatest reduction in total solids and volatile solids was also obtained in this digestor by 76.6 and 79%, respectively, compared to the control reactor. [ABSTRACT FROM AUTHOR]

The unwashed alkali-treated lignocellulose can be directly enzymatically hydrolyzed and fermented via pH adjustment with acids. The use of acids would give a burden on production cost. Furfural residue (FR) which is the acidic solid waste from lignocellulose-derived furfural production process was employed in this study as a pH regulator. The corn cob-derived FR was used to adjust the pH value of alkali-treated corn stover (PCS) to 4.8 for enzymatic hydrolysis and ethanol fermentation. The unwashed PCS adjusted by FR got higher enzymatic hydrolysis efficiency (EHE) than the washed PCS samples. Meanwhile, the mixing of PCS and FR had a synergistic effect on the EHE of PCS. The fermentation of enzymatic hydrolysate from unwashed PCS-FR mixture at 20% solid concentration could attain ethanol production of 26.54 ± 0.02 mg/mL with a yield of 89.53 ± 0.08%. This work created a novel recycling way of FR as a pH regulator for improving the bioconversion of alkali-treated lignocellulose. It also provided a novel clue for the valuable valorization of wastes from corn production. [ABSTRACT FROM AUTHOR]

This study aimed to determine the contamination level, seasonal distribution and the persistence of Salmonella sp, Vibrio cholera, and E. coli in well waters located near municipal solid and liquid waste dumpsites in Zaria, Kaduna State, Nigeria. A total of 186 samples: well water samples (96), soils from waste dump sites (72) and waste water (18), were collected for this study. Samples were plated using freshly prepared molten plate count, Eosine methylene blue agars, poured and swirled properly for a uniform mixture. The presence of E. coli, Salmonella, and Vibrio sp were determined for the two seasons (dry and wet). The bacteria count revealed a significant difference between well waters, soil samples, liquid waste and the control (total plate count - p < 0.005; 0.0001, total coliform count - p < 0.005; 0.0021). All the sampled well water had coliform counts higher than the recommended standard. The counts were higher in the wet season than the dry season. Out of a total of 125 suspected isolates tested, 70 (56%) were positive for Vibrio cholerae, out of this, 38 (54.3%), 28 (40%) and four (5.7%) isolates were from well water, solid waste dumps and liquid waste respectively. Out of the 177 suspected E. coli isolates from well water, solid waste dumps and liquid waste tested, 162 (91.5%) were positive with 82 (50.6%) of the positive E. coli further confirmed to be E. coli 0157:H7. The results showed significant (p < 0.05) statistical difference between the wet and the dry seasons for all the water samples studied and between control and the other well water samples. Adequate treatments of well water, as well as public health education are highly recommended. [ABSTRACT FROM AUTHOR]

Fluorine-containing silicon residue (FSR) is a solid waste that is harmful to the environment. A new alkali-free liquid accelerator based on aluminium sulfate (LAFS) was prepared using FSR. The addition of LAFS to cement mortar shortened the setting times and significantly improved the early strength. With the addition of 8% LAFS, the initial and final setting times were 2.48 min and 11.83 min, respectively, and the 1-day compressive strength was 14.6 MPa, which was 200% of that of the mortar without LAFS. The mechanism of the action of LAFS was studied using isothermal calorimetry test, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and other analytical methods. The results showed that the LAFS rapidly generated a large amount of ettringite and promoted the formation of calcium silicate hydrate in the cement paste. A conceptual model of the early hydration process of cement paste with added LAFS was established based on the analytical results. [ABSTRACT FROM AUTHOR]

The study of the adhesion properties between asphalt and aggregate plays a critical role in deciphering the fracture behavior and damage characteristics in asphalt mixtures. This research is dedicated to exploring the impact of various aging behaviors on adhesion properties and the reinforcing effects of modifiers. In this context, a novel composite modifier (MPM), was synthesized from phosphogypsum whisker, derived from phosphogypsum waste. Asphalt specimens, encompassing both virgin and modified asphalt with the different dosages of MPM, were prepared under a spectrum of eight aging conditions. The mechanical properties of these specimens were meticulously analyzed using multiscale tests to assess the adhesion properties under diverse aging conditions and modifier dosages. Furthermore, the study delved into the microscopic effects of aging and modification on adhesion properties. The results highlighted that aging detrimentally impacts the adhesion properties of asphalt, with this negative effect progressively intensifying over time. In contrast, the enhancement of adhesion properties by MPM exhibited variation in accordance with its dosage. Limestone, characterized by a rougher external interface and a higher prevalence of high-valent cations, demonstrated more pronounced adhesion properties to asphalt compared to granite. The aging process introduced new diffraction patterns and characteristic peaks in the asphalt, with their intensities showing a direct correlation with the duration of aging. The MPM modification was found to effectively mitigate the deterioration in the structural stability of the virgin asphalt. Overall, this study offers comprehensive insights into the aging and modification mechanisms affecting adhesion properties between asphalt and aggregate, contributing significantly to the resource utilization of solid waste. [ABSTRACT FROM AUTHOR]

Incineration bottom ash (IBA) is a by-product generated from incineration of municipal solid wastes, and it is mostly landfilled, especially for fine IBA. Reusing IBA with waste soils as filling materials in civil engineering can be a potential solution. However, the existing studies only focused on the air-cured IBA-soil mixtures in the laboratory, whereas in the field, the mixtures may contact water or immerse in water. Because IBA is rich in sulfates, the stability of IBA-soil mixtures in water may be compromised. Therefore, this study investigated the stability of IBA-marine clay (MC) mixtures in water. Ordinary portland cement (OPC) and granulated blast-furnace slag (GGBS) served as binders to stabilize/solidify IBA-MC. The appearance, strength, mineralogy, and microstructure of IBA-MC, OPC-IBA-MC, and GGBS-IBA-MC were studied. The results showed that all mixtures performed well when cured in air, but some deteriorated after soaking in water. IBA-MC and OPC-IBA-MC subjected to a short precuring period developed significant cracks and strength loss. Long precuring can reduce or eliminate the cracks on specimens during soaking, leading to higher strength. However, GGBS-IBA-MC had no surficial defects and only a slight strength decrease under both precuring periods. The mineralogy and microstructure of IBA-MC and stabilized IBA-MC revealed that the formation and growth of ettringite were responsible for the deterioration of IBA-MC and OPC-IBA-MC soaking in water. [ABSTRACT FROM AUTHOR]

Phosphogypsum (PG) is an industrial solid waste generated during the preparation of phosphoric acid, which is produced in large quantities and stockpiled or discharged into the sea. This study aims to design sustainable pavement base materials constituting significant PG content. The physical and chemical properties of the raw materials were first tested. The optimum moisture content and maximum dry density of specimens were determined by compaction tests. The unconfined compressive strength (UCS), split tensile strength (STS), freeze-thaw cycles, and shrinkage tests were used to evaluate the mechanical performance of phosphogypsum pavement base material (PPBM). Furthermore, the interaction mechanism was investigated by applying scanning electron microscope (SEM) and Fourier-transformed infrared (FTIR) tests. The results showed that the 7-day UCS of PPBM with cement content 8%–12% was greater than 3 MPa. The specimens retained 91.3% unconfined compressive strength over five freeze-thaw cycles. Unlike traditional semirigid base materials, the PPBM exhibited no shrinkage strain, which is manifested by the growth of expansion strain with increasing amounts of PG. Through microscopic observation, the PPBM produced ettringite (AFt) and calcium-silicate-hydrate (CSH) with the extension of curing time, which is consistent with the analysis of FTIR spectrums. The crystallized water in the PG participates in the hydration reaction. [ABSTRACT FROM AUTHOR]

Bentonite, used as a barrier material in landfill systems and the geological disposal of radioactive waste, undergoes various processes such as the cation exchange with landfill leachate and repository groundwater, desiccation shrinkage due to heat released from solid waste or nuclide decay. In the context of these engineering applications, it is crucial to consider the effect of interlayer cation composition on the desiccation-shrinkage behavior of bentonite for assessing the long-term performance of barrier systems. This study investigates this impact by conducting desiccation tests on four different cation-type bentonite samples (i.e., K-, Na-, Ca-, and Mg-bentonite) and elucidating the underlying mechanisms through mercury intrusion porosimetry test, X-ray diffraction analysis, and suction measurements. The results indicate that K-bentonite exhibits the highest water evaporation rate and the lowest shrinkage potential, with no shrinkage cracks detected, and that Na-bentonite evaporates water at a relatively fast rate but presents the most pronounced volumetric shrinkage. In contrast, Ca- and Mg-bentonite have the highest water-retention capacity, and their shrinkage potentials are less than Na-bentonite. An improved shrinkage model is proposed, which is shown to describe the measured shrinkage curves for four types of homoionic bentonite samples. Additionally, the mechanism behind the effect of different interlayer cations was interpreted in terms of the interlayer–cation–water interaction, pore structure evolution, and soil suction variation. [ABSTRACT FROM AUTHOR]

The management of Municipal Solid Waste (MSW) establishes a decisive facet in the development of sustainable and vigorous societies that requires an adequate framework in order to prevent a risk of environmental pollution. Therefore, it's imperative to establish a robust framework to handle the generated MSW. In this regard, early predictions of waste generation with high accuracy emerges as a pivotal factor in serving the municipal authorities to formulate an effective MSW management system. Various researchers have significantly contributed to the field of early waste predictions by developing different deep learning models to attain the highly accurate predicted results. However, it is important to note that each model has its strengths and limitations. This study has predominantly focused on the enhancement of the Gated Recurrent Unit (GRU) model. The primary limitation in the standard GRU model lies in both of its gates (reset and update) processing the identical data. This redundancy has contributed to a prolonged training time and a diminished convergence rate. Therefore, this study has proposed an enhanced GRU model with optimized update gate (EGRU-OU) to address the redundancy issue that lies between the two gates. The EGRU-OU model will provide the filtered data specifically to the update gate which is instrumental in significantly reducing the redundant information between the two gates. Moreover, this study has employed two different datasets to conduct a comprehensive analysis of the results. One dataset has been collected for 16 different developed countries, whereas, the other dataset has been collected for Multan City, Pakistan. These datasets have been segmented into three subdivisions: training data, constituting 70% of the dataset for model training; testing data, comprising 15% for model evaluation; and validation data, representing the remaining 15% for additional model validation. In addition, The EGRU-OU model has been compared with other benchmark models including standard GRU model, Long Short Term Memory (LSTM) and Artificial Neural Network (ANN) model based on three distinct error metrics: Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and the coefficient of determination (R²). The outcomes have clearly demonstrated a superior performance of the EGRU-OU approach as compared to other models with the least error matrices values of MAE being 0.036 and RMSE being 0.0684. [ABSTRACT FROM AUTHOR]

This work deals with the basis for the development of a method for the characterisation of shredders in the field of waste treatment. Therefore, many parameters of shredders have to be considered. In this work, the throughput and its inconsistency come into focus. The fluctuating mass and volume flow rates often cause problems for waste treatment plants. Mixed waste generates a fluctuating throughput despite continuous feeding, often starting at the first machine, the shredder. Dynamic control of the shredder is seen as a solution. By implementing a control loop at the shredder, fluctuations in output are to be minimised, and the idea is that subsequent machines will thus be ideally fed. Autocorrelation of the data of an output volume flow of the shredder exists, which indicates that a dynamic output feedback control can work; therefore, an attempt was made to control the shredder. However, the first control attempt was probably too rudimentary, and implementing a dynamic control of the shredder did not yet improve throughput fluctuations. Nevertheless, the work provides indications and shows potential for further research approaches on the control-based improvement of shredders' throughput continuity. [ABSTRACT FROM AUTHOR]

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Innovations in the field of science and technology transferred to engineering applications led to the rapid pace of urbanisation across the globe. The impact of urbanisation and change in lifestyle of the society is producing thumping municipal solid wastes of 62 million tonnes per year in our ecosystem and its concomitant environmental issues, which need to be addressed critically. Processing of the waste collected can be conducted only on 34.14% of the collected wastes remaining are dumped openly. This paper critically reviews different techniques to convert municipal waste to useful products with specific emphasis on municipalities of India because of its diversified terrain and culture. It is observed that 0.44 kg/capita/day, per capita waste, is generated in metro cities of India. The management and processing of these wastes are analysed. Reprocessing of non-renewable wastes for structural applications from this municipal waste into novel composites is discussed here. Cost and energy-efficient composite materials can be fabricated using biodegradable waste materials, detailed fabrication methods and mechanisms are discussed in this review. Carbonised biodegradable waste is used as reinforcement with an aluminium matrix, exposing the opportunities to use it in composite applications. The challenges and research scopes are briefly discussed in this paper. [ABSTRACT FROM AUTHOR]

Methane (CH4) is a potent greenhouse gas and the second highest anthropogenic emissions are recorded from CH4 on Earth. Considering its high global warming potential, the monitoring of source locations is inadvertent. The paper presented here is the first attempt (to the best of our knowledge) to comprehensively analyse the methane emissions over multiple Indian locations using satellite data. It outlays a brief background of methane emission sensors and studies carried out worldwide for estimation of the GHG. It further enumerates the potential of Earth Surface Mineral Dust Source Investigation (EMIT) and TROPOspheric Monitoring Instrument (TROPOMI) in highlighting the potential point sources of methane emissions and its concentration/emission flux in India. 17 unique plumes were identified using EMIT in the states of Maharashtra (06), Rajasthan (04), Punjab (02), Gujarat (03) and Assam (02). Gujarat, Surat, Assam Uttar Pradesh and Haryana using TROPOMI were also studied. The hotspots showcase emission sources from solid waste landfill sites, sewage treatment plants, wetlands/marshy agriculture, city sewage outlets, oil and gas fields, oil refinery and textile industry. It was observed that EMIT can effectively be used for point source identification, monitoring and enhancement while TROPOMI is best suited for regional level methane monitoring. A sewage outlet plume in Maharashtra produced the maximum emission of 6202.9 ± 691.94 kg/hr followed by solid waste (SW) sites located in Pirana Landfill, Ahmedabad and Khajod Landfill, Surat in Gujarat. Methane monitoring is an important step towards mitigating enormous methane emissions and anomalous methane sources. [ABSTRACT FROM AUTHOR]

One of the most pressing environmental issues is how to properly dispose of municipal solid waste (MSW), which represents both a substantial source of concern and a challenge. The current study evaluated cobalt (Co) accumulation in MSW, their uptake by different vegetables grown for two years, and related human health risks. Vegetables were grown in four different groups, such as one control (ground soil), and the remaining treatment groups (T1, T2, and T3) received varying concentrations of MSW. The analysis of Co was done through an atomic absorption spectrophotometer (AAS). Results revealed that the concentration of Co was higher in all the vegetables (n = 15) grown in soil supplemented with 75% MSW during 2nd growing year. Among all vegetables, the highest concentration of Co was observed in Solanum tuberosum at T3 during 2nd growing year. The pollution load index (PLI) value for vegetables during both growing years was more than 1 except in control soil. The findings indicated that the highest enrichment factor (EF) and hazard resilience index (HRI) value of 0.09 was present in S. tuberosum. Health index values for cobalt in the study were below 1. The HRI < 1 indicated that consumers do not face any immediate health risks. The investigation of Co concentrations in blood samples obtained from individuals residing in different areas contributes a human health perspective to the research. The findings indicate that the concentration of Co rises with an increasing proportion of MSW. While the metal levels in MSW-treated soil were not high enough to classify the soil as polluted, the results recommend that recycling MSW can substitute mineral fertilizers. Nevertheless, the presence of cobalt in MSW may directly affect soil fertility and could impact crop production and human health. [ABSTRACT FROM AUTHOR]

This study examined plastics and toxic metals in municipal solid waste compost from various regions in Sri Lanka. Plastics were extracted using density separation, digested using wet peroxidation, and identified using Fourier Transform Infra-Red Spectroscopy in Attenuated Total Reflection mode. Compost and plastics were acid-digested to quantify total Cd, Cu, Co, Cr, Pb, and Zn concentrations and analyzed for the bioavailable fraction using 0.01 M CaCl2. Notably, plastics were highly abundant in most compost samples. The main plastic types detected were polyethylene, polypropylene, and cellophane. However, the average Cd, Cu, Co, Cr, Pb, and Zn levels were 0.727, 60.78, 3.670, 25.44, 18.95, and 130.7 mg/kg, respectively, which are well below the recommended levels. Zn was the most bioavailable (2.476 mg/kg), and Cd was the least bioavailable (0.053 mg/kg) metal associated with compost. The Contamination factor data show that there is considerable enhancement of Cd and Cu, however, Cr, Cu, Co, and Pb are at low contamination levels. Mean geo accumulation index values were 1.39, 1.07, − 1.06, − 0.84, − 0.32, and 0.08 for Cd, Cu, Co, Cr, Pb, and Zn. Therefore, the contamination level of compost samples with Cd and Cu ranges from uncontaminated to contaminated levels, whereas Co, Cr, Pb, and Zn are at uncontaminated levels. Despite no direct metal-plastic correlation, plastics in compost could harm plants, animals, and humans due to ingestion. Hence, reducing plastic and metal contamination in compost is crucial. [ABSTRACT FROM AUTHOR]

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The residue generated during the production process of alumina, known as red mud, is a type of solid waste. The engineering properties of red mud can be significantly enhanced through the modification and solidification using inorganic materials. This study primarily utilized red mud as the raw material, supplemented with fly ash, lime, and clay, to conduct a solidification experiment of red mud. Orthogonal tests with three factors of two ash ratio (ratio of lime to fly ash), two ash content (total lime and fly ash), and red mud types were designed to study the changes of different ratios and maintenance conditions, etc., on the engineering properties of red mud. In addition, the micro-mechanisms of modified red mud were investigated by means of XRF, XRD, SEM and EDX. The results show that for optimum moisture content, red mud types are the most important influencing factor and for maximum dry density, two ash content is the most important influencing factor. For strength characteristics, the optimum two ash ratio was 1.5:1, the optimum two ash content was 50%, and the optimum red mud types were 70% CRM (red mud made of Chalco Shandong Co., Ltd) mixed with 30% clay. The addition of lime, fly ash, and clay improves the temperature shrinkage coefficient of the red mud. Through the analysis of microscopic composition and structure, it can be seen that goethite (α-FeO(OH)) and magnetite (γ-Fe2O3) in the red mud reacted with the modified materials to generate crystalline aluminosilicate and amorphous hydrated silicate gel, and these products together with the original calcium carbonate (CaCO3), tricalcium aluminate (Ca3Al2O6) and garnet (Ca3TiFeSi3O12) in the red mud which have certain strengths enhance the structural strength of the modified red mud. The optimum ratio obtained from the combined test results was lime: fly ash: CRM = 30:20:50. Therefore, using lime, fly ash and clay as modified materials can greatly enhance the engineering properties of red mud and realise the resourceful use of red mud. [ABSTRACT FROM AUTHOR]

Brunei, similar to other nations, encounters difficulties in effectively managing solid waste, with 70% of the waste ending up in landfills, 2% through composting, and the remainder being disposed of through conventional methods. The current landfill site is anticipated to reach its maximum capacity in 2025. Energy recovery from waste is crucial for Brunei since it can improve waste management, mitigate environmental consequences, produce economic advantages, bolster energy security, and promote a circular economy. This study aims to identify the potential for energy recovery through landfill gas generated from solid waste disposal in Brunei Darussalam. The study finds that Brunei Darussalam can produce 129 thousand tonnes of CO2e/year landfill gas. Utilising gas to generate electricity of 367 GWh could save 1.6 million USD annually. In addition, it also identifies the strengths and weaknesses of the existing solid waste management in Brunei Darussalam. Furthermore, it formulates a waste management policy in Brunei Darussalam by identifying relevant stakeholders to overcome the weakness. Lastly, the framework for waste management is designed to consider short-, intermediate- and long-term goals and targets, with actions to be taken by respective stakeholders. [ABSTRACT FROM AUTHOR]

Integrating anodic coal gasification fine slag oxidation with cathodic hydrogen evolution reaction presents an environmentally friendly and energy-efficient solution for solid waste recycling and hydrogen production. This innovative approach exhibits higher activity and stability than conventional water electrolysis, while also preventing anode degradation due to its benign reaction conditions. The kinetic investigations have revealed that slag oxidation occurs more rapidly than water oxidation. Specifically, slag undergoes direct and indirect oxidation within the potential regions below and above those of water oxidation, respectively. This study has the potential to shed light on the mechanisms underlying slag electrolysis and offer valuable insights for the simultaneous recycling of solid waste and hydrogen production. [ABSTRACT FROM AUTHOR]

Dumpsites generate leachates containing bacteria that may carry antibiotic resistance genes, such as extended spectrum β-lactamase (ESBL). However, the contribution of dumpsite leachates in the environmental spread of ESBL genes has not been investigated in greater detail. This study aimed to quantify the impact of Ajakanga dumpsite leachate on the spread of ESBL genes through surface water. The susceptibility of Escherichia coli isolated from dumpsite leachate and the accompanying surface water to selected antibiotics was assessed by the standardized disc diffusion method. The isolates were evaluated for phenotypic ESBL production using the double disc synergy test (DDST). The detection of ESBL genes in the isolates was carried out using a primer-specific polymerase chain reaction (PCR). Escherichia coli isolates from leachate (n = 26/32) and surface water (n = 9/12) expressed ESBL phenotype. The ESBL-producing isolates showed the highest level of resistance to the 3rd generation cephalosporin antibiotics: cefotaxime (100%), cefpodoxime (97%), ceftazidime (97%), with low resistance observed to imipenem (6%) and azithromycin (3%). All the isolates were multidrug-resistant, showing resistance to three or more classes of antibiotics. All the ESBL-producing E. coli obtained carried blaCTX−M, 21/35 (60%) carried blaTEM while none of the isolates bore blaSHV. This study found that ESBL-producing Escherichia coli from dumpsite leachate and nearby surface water had identical resistance signatures indicating the relatedness of the isolates, and that dumpsite leachate could contribute to the transfer of ESBL-producing bacteria and their genes to receiving surface water. This study has necessitated the need for a review of the guidelines and operational procedures of dumpsites to forestall a potential public health challenge. [ABSTRACT FROM AUTHOR]

The application of industrial solid waste coal gangue (CG) in gas explosion suppression is explored, which opens up a new way for the resource utilization of CG. Two modified CG anti‐explosion agents, first‐grade modified CG (RCG) and second‐grade modified CG (MCG), were prepared by roasting activation and acid–base synergistic excitation. The explosion suppression performance of CG, RCG, and MCG was investigated through a 2.5 L semi‐closed explosion pipe. The experimental results were compared and analyzed, and their pyrolysis characteristics, phase composition, and particle size were analyzed to reveal their explosion suppression mechanism. It was proved that MCG had the best explosion suppression effect. Under the condition of 9.5% methane–air, it was found that the explosion suppression effect was most significant when the powder mass of the three powders was 300, 360, and 360 mg, respectively. The peak explosion overpressure is reduced by 10.51%, 21.96%, and 32.66%, respectively, and the peak arrival time of flame velocity is extended by .14 times, .20 times, and 1.15 times, respectively. MCG can effectively inhibit methane explosion utilizing physical and chemical synergistic heat absorption, porous structure formation barrier, heat isolation, oxygen dilution, adsorption, and capture of free radicals. [ABSTRACT FROM AUTHOR]

Tannery solid waste (TSW) contains 70–90% collagen by weight. The rapid extraction of collagen while preserving its original and unique triple-helical conformation has proved challenging. In this paper, an ionic liquid-synergistic dissolution and regeneration (IL-SDR) method was developed based on a TBAH/DMSO/H2O ternary (TDH) solvent for the rapid recovery of collagen from TSW under mild conditions. A solubility of 10.25% TSW and a collagen recovery yield of 51.2% were achieved in 30 minutes at room temperature. The original triplet helical conformation and the molecular weight of the collagen product were retained, confirmed via FT-IR, circular dichroism, and matrix-assisted laser desorption/ionization time-of-flight analysis. SEM was used to verify that dense and uniform pores could be formed within collagen by adjusting the DMSO content, and cytotoxicity and moisture retention tests demonstrated that the collagen produced via the IL-SDR process is comparable to natural collagen used in cosmetic and skincare applications. Moreover, the TDH solvent demonstrated excellent reproducibility across five cycles, achieving consistent solubility varying from 9.71% to 11.04%. EPR and 1H NMR showed that the OH– in TBAH induced the generation of DMSO˙ free radicals in the TDH solvent, and these radicals were indispensable for the dissolution of TSW. The DMSO content was positively correlated with the concentration of free radicals. A synergistic dissolution mechanism was proposed: DMSO˙ free radicals preferentially cleaved the terminal peptide chains, causing the collagen molecules to be exposed to DMSO. Subsequently, DMSO disrupted the original hydrogen bond network within the collagen molecules. Then, TBAH and DMSO formed hydrogen bonds with the collagen molecules, stabilizing the dissolved collagen and preventing the reformation of the hydrogen bond network between collagen molecules. This work provides an avenue for low-temperature and rapid dissolution of TSW, and reveals an in-depth, atypical dissolution mechanism for collagen-based materials during the IL-SDR process. [ABSTRACT FROM AUTHOR]

Background: Poor sanitation safety in municipal solid waste management can cause environmental and public health problems. This is the case in Ethiopia, where the sanitation safety standards are low in the municipal solid waste management operations. Therefore, the sanitation safety practices along the solid waste management service chains in Addis Ababa, Ethiopia are poorly understood, and this research will contribute new insights for the scientific community and can also inform policies and the current solid waste management operations in Addis Ababa. Materials and Methods: This study evaluated the safety of sanitation practices in the solid waste management service chain using a community-based approach in Addis Ababa city from January to August 2023. We have interviewed 384 participants using a cluster-random sampling technique and collected data through direct observations and face-to-face interviews. The study employed descriptive statistics, factor analysis and multiple linear logistic regression to analyze the data. Results: The findings of the study revealed significant variations in sanitation safety practices and risks among households during solid waste management. While 60% of households practiced solid waste segregation, only 15% of them followed safe segregation practices. The majority of households (85%) used unsafe segregation practices, such as mixing different types of waste and storing wet and dry waste together. Additionally, 85% of households used storage and transport containers that had leaks, potentially leading to contamination and infection. Furthermore, the study identified sanitation safety risks and practices at waste collection and transport sites. The risks included solid waste droppings during transport, inadequate vehicle cleaning and disinfection, lack of personal protective equipment (PPE) for workers, and uncovered waste collection vehicles, leading to environmental contamination. At transfer stations, the study found several risk factors, such as the lack of protection from animals and human activities, absence of shower facilities for workers, and inadequate storage facilities for PPE and tools. The transfer stations also lacked odor-neutralizing systems, proper waste handling practices, and physical fly barriers. Workers did not have the opportunity to shower after work, further increasing the risk. The sanitation safety practices and risks at solid waste treatment/disposal sites were also assessed. The study revealed medium risks associated with waste treatment/disposal operations, including working without PPE, handling contaminated containers and raw waste, and releasing airborne particulates that could be inhaled by workers or the nearby community. Factor analysis was conducted to categorize the variables related to sanitation safety practices. Six factors were identified, explaining approximately 60.6% of the overall variance. These factors represented different aspects of sanitation safety, including onsite waste handling practices, failure to maintain proper standards, risks related to unsafe waste storage, failure to properly store wastes at the household level, having safe storage practices, and unsafe waste segregation and storage. The study also examined the association between sanitation safety practices and sociodemographic factors using multiple linear regression analysis. Marital status, education, occupation, and income were found to be significant factors influencing sanitation safety practices during onsite waste handling. Income and marital status had the highest contribution, while occupation had the lowest contribution. Conclusion and Recommendation: the research findings highlight the wide variation in sanitation safety practices and risks associated with solid waste management. The study emphasizes the need for improved waste management practices at the household level, waste collection and transport sites, transfer stations, and waste treatment/disposal sites. The identified risk factors should be addressed through targeted interventions, including public awareness campaigns, proper training of waste management workers, and the implementation of safety protocols and infrastructure improvements. Additionally, sociodemographic factors play a role in determining sanitation safety practices, emphasizing the importance of considering these factors when developing waste management strategies and interventions. [ABSTRACT FROM AUTHOR]

To promote the use of solid waste in concrete production and solve the problem of secondary pollution caused by a large amount of solid waste, the four-factor and four-level orthogonal test method was used to investigate the different replacement rates of coal gangue (CG) ceramics (15%, 20%, 25%, and 30%), coal gangue ceramic sand (CGS) (10%, 15%, 20%, and 25%), fly ash (FA) (10%, 15%, 20%, and 25%), and steel fiber (SF) content (0.30%, 0.60%, 0.90%, and 1.2). By using range analysis, variance analysis, matrix analysis, and regression analysis, the prediction models of primary and secondary factors, optimal dosage, and strength under different factor levels were obtained. The microstructure and strengthening mechanisms of different materials were analyzed by scanning electron microscopy (SEM). The results show that the optimal combination of the CG substitution rate is 30%, CGS substitution rate is 15%, SF content is 1.2%, and FA substitution rate is 10% for cube compressive strength. For the splitting tensile strength, the optimal combination is a CG substitution rate of 30%, CGS substitution rate of 25%, SF content of 1.2%, and FA substitution rate of 10%. The resulting strength prediction model has high accuracy, which can predict the strength within the range selected by the orthogonal test in this paper and provide a reference for the application of steel fibers and solid waste in concrete, which contributes to the energy conservation and emission reduction in the construction industry. [ABSTRACT FROM AUTHOR]

Sawdust, a solid waste generated during stone processing, poses a serious threat to the environment with its untreated accumulation. This paper first analyzes the chemical composition and physical properties of sawdust, and discusses its mechanism of action in cement mortar. By systematically optimizing the blending ratio and modification method of sawdust, the sawdust-modified cement mortar with excellent performance was prepared. This study evaluates the key performance indicators of sawdust-modified cement mortar, such as compressive strength, flexural strength, and durability, through a series of experiments. The experimental results indicate that the incorporation of an appropriate amount of sawdust significantly enhances the mechanical properties of cement mortar, while also improving its durability, particularly in terms of freeze-thaw resistance. Microstructural analysis reveals the mechanism by which sawdust improves the pore structure of cement mortar; the active components in the sawdust react with the hydration products of cement, resulting in the formation of crystalline structures with higher strength. Therefore, the use of sawdust as a modifier in cement mortar can improve its mechanical properties and durability, while simultaneously reducing the accumulation of solid waste and promoting the sustainable development of building materials. [ABSTRACT FROM AUTHOR]

Background: Municipal solid waste (MSW) has increased dramatically in emerging economies like Bangladesh as a result of rapid urbanization and economic growth. Due to the high land requirements and nature of the waste, options of municipal waste management such as landfilling and waste-to-energy have proven to be expensive and inefficient. Previously, a pilot study on a waste-to-compost program in a decentralized facility was done in Dhaka to evaluate the effectiveness of municipal waste management. Objective: The aim of this study was to analyze the life cycle costs (LCCs) of a waste-to-composting facility in Dhaka, Bangladesh. The objective was to ensure economical and effective management of MSW by comparing overall spending to the current and proposed waste management process. Methodology: In order to evaluate the potential of the planned decentralized compost plant, LCC methods using UNEP/SETAC guidelines are used in the study. This includes an additional analysis of environmental and operational costs and benefits. Result: The research found that the overall cost of the decentralized compost facility was $857,110, much less than the expenditures associated with landfilling and conventional composting methods in Dhaka. Conclusion: This study shows that a decentralized waste-to-compost plant may be a profitable option for dealing with municipal solid waste. Its potential to ease stress on municipal governments is highlighted by its much lower price tag. Insightful for policymakers and urban planners in emerging nations confronting comparable waste management difficulties, this research stresses the need to implement such creative, cost-effective approaches in quickly rising metropolitan cities. [ABSTRACT FROM AUTHOR]

An analysis of the pressure factors that influence the sustainable tourism in the Tremiti Islands (TI) has been performed. Tourist's fluxes have been investigated in terms of monthly arrival and presences showing a high value of the territorial exploitation index with high number of arrivals, particularly in August, and low occupancy rate. Effects of climatic change has been analyzed in TI with reference to the increase of average air and sea temperature in the islands. Some measures of contrast to climate change and to favour sustainable tourism have been discussed also. The CO2 emissions by ferries transport, solid waste and wastewater treatment have been calculated. Environmental taxation for sustainable tourism aimed tat CO2 content reduction is also assessed identifying the value in 1.47 €/capita on the basis of the tourist arrivals and presences considering the environmental cost for CO2 removal and showing that tourism taxation should be well accepted if funds are destined to environmental purposes. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Cachaça (Brazilian spirit) is an alcoholic beverage of cultural and economic importance in Brazil. Its artisanal production is usually conducted in copper alembics, which results in contamination. The development of effective biosorbents from cheap matrices is an alternative to minimize both solid waste generation and copper levels in cachaça. The present work evaluates the obtention of nanocellulose‐based materials from the major residue generated during the processing of palm heart from the Brazilian peach palm, through different processing techniques. Materials were characterized by physicochemical composition and their sorbent capacities for copper removal from aqueous solutions, and a simulation was conducted to evaluate potential application in the adequacy of cachaça to meet Brazilian legislation requirements.The different processing methods resulted in different cellulose concentrations, with the highest concentration in the bleached material (B3, 694 g kg−1 of cellulose), and different specific surface areas (1.02–12.4 m2 g−1). Copper adsorption onto nanocellulose obtained from peach palm external sheath is fast, with a predominance of a chemisorption mechanism. Isotherms were best represented by Langmuir's model, suggesting a monolayer adsorption. Simulations indicate that B3 is a suitable material for the removal of copper from cachaça, and small amounts of biosorbent (733.5 g) are required for the reduction of copper concentrations (10 to 3 mg L−1) in 1000 L of cachaça.This study demonstrated that the obtention of biosorbents from peach palm solid residues is promising and this nanocellulose‐based material can be used for copper removal from contaminated cachaça. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Chiton articulatus is a species of mollusk living in the tropical Pacific intertidal rocky shores of Mexico. This species feeds on solid waste organic sources, including hard crustose algae that grow on rocky substrates, by grazing on them with its radula, a flexible chitinous membrane lined with mineralized major lateral teeth. In this study, the composition, morphology, and resulting mechanics of the mature teeth of this species, which have yet to be examined, are revealed. The results show the presence of multiphasic mature teeth, each consisting of aligned hard magnetite nanoparticles on the leading edge of the tooth underneath which are magnetite lamellae, followed by goethite, lepidocrocite, and eventually hydroxyapatite near the trailing edge. This multiregional structure demonstrates a gradation in hardness as well as different microstructural features integrated with tough interfaces. The combination of these microstructural and phase arrangements results in an abrasion‐resistant tough structure with a self‐sharpening ability. The results of this work will help contribute to developing new bioinspired designs while also helping to understand the evolution and feeding habits of these intriguing invertebrates. [ABSTRACT FROM AUTHOR]

The use of solid waste such as coal and biomass co-fired fly ashes and sewage sludge fly ash instead of clay and other non-renewable resources to produce lightweight aggregates (LWAs) is conducive to sustainable development. In this study, the effects of co-fired fly ashes, sewage sludge fly ash and quartz sand proportion, sintering temperature and sintering time on the physical properties and microstructure of LWAs are studied by single factor experiment. Experimental results show that the optimal experiment conditions are the raw material ratio of co-fired fly ashes: sewage sludge fly ash: quartz sand = 9: 1: 4, 2 wt% SiC as an expansion agent, and sintering at 1060 °C for 10 min. The LWAs obtained under the above conditions have a bulk density of 0.85 g/cm3, an apparent density of 1.84 g/cm3, a 1-h water absorption of 2.71 %, and a compressive strength of 8.68 MPa, which are in accordance with the GB/T17431.1–2010 standard. Besides, the heavy metal immobilization effect of the LWAs is satisfying, where the heavy metal leaching concentrations meet the standard of GB5085.3–2007. In conclusion, it is feasible to use the raw materials to prepare the LWAs under the above sintering conditions, and the prepared LWAs have high strength and low water absorption. [ABSTRACT FROM AUTHOR]

A study was conducted to identify the effects of aging on the biodegradability of vermicomposts in soil. Two solid wastes, including cow manure (CM) and wheat residues (WR), were subjected to the vermicomposting. The products of the various ages were mixed with Lavark and Langroud soils and incubated for 45 days. Results indicated that the aging effects led to an increase in the lignin (LG) content. Potentially, mineralizable C was decreased from 5308 mg C kg−1 for fresh substrates to 1643 mg C kg−1 for aged CM vermicompost in the Lavark soil. The decreasing trend was also observed for the Langroud soil. Similar behavior was also shown for the soils when treated with WR vermicomposts of different ages. The age of vermicomposts was negatively correlated with potentially mineralizable C as well as LG and C/N ratio. Multiphase decomposition was observed, in particular when the products of the early ages were used. The aging of CM and WR induced a decrease in the number of decomposition phases. Overall, by aging, the less biodegradable fraction (lignin) accumulates, and the patterns of decomposition tend to decrease the number of decomposition phases or decrease the last phase biodegradation rate constant. [ABSTRACT FROM AUTHOR]

AbstractGarbage incineration power generation is utilized to dispose of multi-source organic solid waste. This work constructed a mathematical model for a 750 t/d garbage incinerator to reveal the coupled response between the boiler and furnace sides. Field experiments validated the model, exploring various operating conditions including different loads, fuel blending ratios, primary air, and internal flue gas recirculation (IGR) air flow rates. Increasing the load by 9.1% raised furnace heat exchange by 4.0% but reduced economizer heat exchange by 19.0%. Introducing waste cloth strips and paper mill waste enhanced furnace water-cooled wall heat transfer but reduced economizer heat exchange. A 10.8% rise in primary air flow increased superheater heat exchange by 7.8%. Similarly, a 21.3% rise in IGR air flow increased economizer heat exchange by 9.0%. The temperature rise and enthalpy rise in the superheater were higher when the low calorific value of the fuel was higher. Increasing primary air velocity enhanced heat transfer, raising the outlet temperature of the medium-temperature superheater, necessitating an increase in secondary water spray to adjust the outlet temperature of the high-temperature superheater. This work provides guidance for the design and practical operation of multi-source solid waste incinerators. [ABSTRACT FROM AUTHOR]

In this study, a composite modifier (CMCDL) containing coal gasification residue, dicyandiamide waste slag, and lake sediments was used to modify steel slag at high-temperature. Five kind of raw materials was analyzed in physicochemical properties, mineral composition and microstructure, cementitious properties and soundness, and particle size analysis, the same to steel slag after high-temperature modification (SHTM). The new mineral phases were found that tricalcium aluminate (C 3 A), gehlenite (C 2 AS), magnetite (Fe 3 O 4), spinels (MgFe 2 O 4), quartz (SiO 2), celite (C 6 AF 2) and diopside (CMS 2) formed in the SHTM when the mass fraction increase from 10% to 30% in CMCDL. The HTM with CMCDL increases the glass phase and hydrated mineral (C 3 A, C 3 S, C 2 S) and in raw steel slag, promoting the disassembled of RO phase, turning the phase from FeO into MgFe 2 O 4 and Fe 3 O 4. MgFe 2 O 4 and Fe 3 O 4 have similar crystal structures, and they form mixed spinels. When the content of CMCCL (coal gasification residue: dicyandiamide waste slag: lake sediments =7:9:4) is 20%, the temperature is 1250 °C, result showed that the mass fraction of f-CaO in SHTM using CMCCL decreases from 4.81% to 1.86%, with a decrease of 61.3%, the 28-day activity index of SHTM increases up to 17.6% compared with raw steel slag, reaching 86.2%. Therefore, the CMCDL-blended SHTM can be applied harmlessly in cement and concrete, enabling low-energy fine grinding of steel slag. [ABSTRACT FROM AUTHOR]

As global concerns about climate change intensify, the need for effective strategies to reduce carbon emissions, has never been more urgent. This review paper explores the crucial role of digital technologies (i.e., data automation (DA) and decision support systems (DSSs)) in enhancing decision making and achieving a ZERONET initiative (decarbonation efforts) within the realms of solid waste management (SWM), wastewater treatment (WWT), and contaminated soil remediation (CSR). Specifically, the paper provides (a) an overview of the carbon footprint (CFP) in relation to environmental management (EM) and the role of DA and DSS in decarbonization; (b) case studies in areas of SWM, WWT, and CSR in relation to the use of (i) digital technology; ((ii) life cycle assessment (LCA)-based DSS; and (iii) multi-criteria decision analysis (MCDA)-based DSS; and (c) optimal contractual delivery method-based DSS case studies in EM practices. This review concludes that the adoption of DA and DSSs in SWM, WWT, and CSR holds significant potential for enhancing decision making and decarbonizing EM processes. By optimizing operations, enhancing resource efficiency, and integrating renewable energy sources, smart EM technologies can contribute to a reduction in GHG emissions and the promotion of sustainable EM practices. As the demand for more effective and eco-friendly solutions grows, the role of DA and DSSs will become increasingly pivotal in achieving global decarbonization goals. [ABSTRACT FROM AUTHOR]

A major issue recurrent in sustainability ensuring concerns is pollution due to human activities, mainly related to the reduction in waste generation. The present study aims to identify students' awareness of waste management, their daily routines in separately collecting recyclable waste, and their behaviors leading to reducing wasteful consumption in campus residential living, in a large university in the Western part of Romania, to channel the strategic plan of the university and the efforts of institutional teams dealing with the issues of waste management and sustainability. The methodology consists of an analysis of waste management in the university campus hosting around 6000 students in 16 dormitories, and of an anonymous online survey mapping the self-perceived behavior of students in solid waste management. Data from 1172 valid responses are refined through factorial analysis. While recycling behavior seems to be largely shared by the respondents, with more than 50% declaring that they always reuse recyclables, separate collection of waste is typical for only a quarter of the sample. Therefore, a vigorous intervention is needed to guide young adults' behavior towards sustainability choices. Campus greening needs to join interventions from the university, in charge of campus life in the selected case, city administration, waste management companies, and the student body. The findings are useful to explore the possible directions for action to increase or contribute to territorial sustainability in the socio-ecological context of Timisoara, the largest university city in the western part of Romania through educational, managerial, and policy interventions, based on local partnerships and collaborations, in accordance with SDG 17. [ABSTRACT FROM AUTHOR]

Prior research has demonstrated that incorporating solid waste from various sources, such as plastics, civil engineering waste, and industrial and mining waste, into pavement and civil works mixes has notable environmental benefits. This includes reducing the over-exploitation of aggregate banks and preventing waste materials from being deposited in open-pit landfills for extended periods. This review focuses on sustainable aggregates produced from solid waste with rheological or mechanical properties suitable for replacing conventional aggregates in asphalt or hydraulic concrete mixtures. The aim is to determine the optimal replacement percentage in the mixture to directly impact pavement performance. This review also delves into the impact on fatigue resistance and permanent deformation based on the type of waste material used in construction. Additionally, using sustainable aggregates presents added benefits for pavement binders, such as inhibiting reflection cracks, reducing traffic noise, and prolonging the service life of the pavement. However, it is crucial to study the percentage of replacement of sustainable aggregates in conjunction with other materials using mathematical models and simulations to ensure a substantial contribution to the sustainability of the construction industry. [ABSTRACT FROM AUTHOR]