Journal of Material Cycles and Waste Management最新文献

Mushroom cultivation is an important branch of the agricultural industry, and global mushrooms production has increased more than sixfold in the last decade. This industry uses large amounts of agricultural, forestry, livestock, and industrial wastes and their by-products. However, it also generates millions of tons of spent mushroom compost (SMC) (approximately 100 million tons per year) which has emerged as a significant issue that hinders the growth of the mushroom business and impacts the environment. Many crop diseases, which cause significant economic losses, are introduced by soil-borne plant pathogens. Spreading spent mushroom compost (SMC) to agricultural soils is a natural way to control plant diseases. Using organic waste material instead of chemicals, which is the most widely used method in agriculture today, is also a more environmentally responsible option. The generated SMC can potentially be used as a soil conditioner, an organic fertilizer, and suitable medium for growing various vegetable crops. The application of SMC has been found to be beneficial in the control of crop diseases by inducing microbiostasis, direct toxicity, or by inducing systemic resistance of the host plant. In the current review, the practical application of SMC in the cultivation of tomato, pepper, lettuce, cucumber, and eggplant was addressed. The application of SMC as a soil amendment showed a significant improvement in soil properties, including soil NPK, organic matter content, and soil beneficial microorganisms. Our review indicated that SMC could be used as a low-cost, alternative growing medium in vegetable production or as a soil amendment to add nutrients and restore soil fertility in agricultural lands. The SMC may be able to replace peat, a non-renewable natural resource, and thereby mitigating the adverse effects of excessive peat extraction in wetlands, bogs, marshes, and peatlands. This review uses unique data on the effective use of SMC in agricultural disease management, reducing the need for chemical pesticides that have adverse effects on both the environment and human health. It also provides a safe method for reusing, recycling, and integrating SMC into a circular economy that reduces its negative environmental effects and carbon footprint impacts. This work also offers a novel application of SMC as a low-cost substitute for peat or other growing media that pose environmental risks.

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Treatment of textile industry effluents produces hazardous sludge. The improper disposal of sludge causes secondary pollution due to the leaching of heavy metals from it. Therefore, the prerequisite for the disposal of such hazardous sludge is its stabilization and solidification. The utilization of sludge as a resource for building materials is one of the sustainable solutions. The present study evaluates the feasibility of partially substituting cement with the textile common effluent treatment plant (TCETP) sludge and mineral admixture such as sugarcane bagasse ash (SBA) in cement mortar mixes. The 13 mortar mixes are prepared consisting of a control mix, four binary mixes with sludge (2.5, 5, 7.5, and 10%) and eight tertiary mixes with sludge (2.5, 5, 7.5, and 10%) and SBA (5, 10%) replacing cement by volume. Few binary and tertiary blended cement mortar mixes have demonstrated comparable strength, permeation, durability, and leaching properties that are on par with the control mix. The modified mortar mixes 2.5T, 5T, 2.5T5S, 5T5S, and 7.5T5S have improved strength compared to 7.5T, 10T, 10T5S, 2.5T10S, 5T10S, 7.5T10S, and 10T10S. Increased strength in mortar mixes is mainly attributable to the filler effect of sludge and SBA and the development of secondary CSH gel. The mortar mixes 7.5T, 10T, 10T5S, 2.5T10S, 5T10S, 7.5T10S, and 10T10S have increased sorptivity indices showing the presence of large-size pores. Durability results suggest a loss in strength due to sulfate attack. Carbonation is not observed in the mixes, and all the mixes are alkaline. However, the leaching study shows the presence of heavy metals in leachate solution above the permissible limit, mainly with mixes having 10% sludge and is within the permissible limit for all other mixes. The SEM image and XRD fingerprint analysis revealed the formation of porous structure and a reduction in CSH gel formation at higher replacement by sludge and SBA.

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Municipal solid waste (MSW) management poses significant environmental and health risks due to lack of source segregation, and reliance on landfills. To address these challenges, a prototype segregator is designed to process MSW, eliminating the need for a bio-drying process. A lab-scale density media separator (DMS) is developed for pre-experimentation and feasibility analysis of nine samples ranging from 100 to 500 g. Feasibility analysis indicates the possibility of the proposed process being implemented as a prototype and also creates the baseline considerations for designing the prototype segregator. Performance analysis of the prototype reveals the segregation of mixed MSW into plastic waste (lower specific density, larger particle size: 30–50 mm) with recovery of 81%, while Inert waste (higher specific density, smaller particle size: 5–45 mm) with recovery of 42%; and degradable waste (specific density closer to water and particle size 5–20 mm) with recovery of 78%. Furthermore, parametric optimization redefines the recovery of plastic by 78% (at 55 mm particle size, 300–400 L water), degradable by 48% (at 40 mm particle size, 250–375 L water, agitation 21.8–10.9 min). Thus the proposed system offers promising solutions to improve MSW management and alleviate environmental impact.

Phosphogypsum (PG) is a byproduct of phosphoric acid production and consists mainly of calcium sulfate (CaSO₄). PG management is a critical concern in the phosphoric acid industry. As a solution, PG is decomposed to extract sulfur dioxide (SO₂), which is recycled to produce sulfuric acid (H₂SO₄). Carbon monoxide (CO) decreases the temperature of PG decomposition, producing calcium monoxide (CaO) and calcium sulfide (CaS). This work aims to develop a kinetic model of PG decomposition under reductive conditions by considering the effect of CO partial pressure on the reaction scheme and kinetics. The tests performed with a thermogravimetric analyzer (TGA) at several CO partial pressures and a thermodynamic study indicate that PG decomposition produces CaS and CaO as parallel reactions, while the selectivity towards each of the products depends on the temperature and CO partial pressure. As part of the kinetic study, the kinetics triplet of CaS and CaO production were individually estimated. The activation energy for each reaction, CaS and CaO production, was defined as 259.0 and 140.3 kJ/mol, respectively. The overall kinetic model of PG decomposition with CO reveals that both diffusion and interface reaction (reaction on the surface and adsorption) are equally controlling steps. The PG reduction with CO is achieved by CO adsorption on the CaSO₄ surface.

The disposal of waste bottom ash (WBA) is an environmental and economic challenge for the manufacturer. Therefore, disposal of waste bottom ashes is important for sustainable production. In this study, the usability of WBA instead of cement in the mortar was investigated. For this purpose, the workability, ultrasonic pulse velocity (UPV), flexural strength (f_f), compressive strength (f_c), microstructure, and hazard potentials of mortars containing WBA were examined. Effect levels of the selected variables (replacement ratio: 0%, 5%, 10%, 15%, 25%, 35%, and 50%, specimen age: 28, 60, and 90 day) on the UPV, f_f, and f_c were determined by ANOVA, and response surfaces were created. UPV and f_c were decreased at all specimen ages with an increasing replacement ratio. The R² of the models for the UPV, f_f, and f_c is higher (0.9660, 0.8034, and 0.9029). According to the leaching test results, Cd, Pb, Hg, and As values of all mortar samples were below the detection limit (not detectable) in this evaluation. The Cr values in all mortar samples remained below the maximum concentration of 5 mg/L, which is the given restriction of TCLP procedure.

The surge in global industrialization has significantly increased greenhouse gas concentrations in the Earth's atmosphere, with carbon dioxide (CO₂) being the predominant contributor to about two-thirds of the greenhouse effect. Landfill gas (LFG), resulting from the biodegradation of municipal solid waste (MSW), mainly consists of methane (CH₄) and CO₂. To counteract uncontrolled CO₂ emissions from waste decomposition, an innovative, low-cost biogeochemical cover (BGCC) system for landfills utilizing biochar-amended soil and basic oxygen furnace (BOF) slag for CO₂ carbonation has been developed. Despite the effectiveness of BOF slag in CO₂ removal, its limited availability near landfill sites presents sustainability challenges, necessitating the search for viable alternatives within the BGCC system that can achieve efficient CO₂ sequestration through direct aqueous mineral carbonation. This review explores various carbon sequestration techniques, identifying potential alkaline industrial solid wastes as substitutes for BOF slag, and evaluates these materials—namely cement kiln dust (CKD), blast furnace (BF) slag, coal fly ash (CFA), and concrete waste—for their compatibility with the BGCC system. CKD is highlighted as having the highest carbonation potential based on its capacity for direct aqueous carbonation, with a comparative analysis revealing substantial differences in the carbonation capacities of the materials. Given the fine-grained nature of the selected materials, the review also emphasizes the need to integrate them into barrier soil layers or use them as standalone layers within the BGCC. In conclusion, this review accentuates the potential of alternative materials in achieving effective CO₂ sequestration within BGCC, thereby addressing the challenges related to the availability of BOF slag and promoting sustainable landfill management practices.

Organic waste salt is a high salt hazardous waste produced by the industrial processes. Presently, there is no viable method to reclaiming and treating this issue. Using the commercial pyrocatechol monois-propyl waste salt from the manufactured pyrocatechol monois-propyl ether, a process was developed for the synergistic extraction and purification of NaCl from pyrocatechol monoisopropyl ether (OP) salt leftovers by low-temperature roasting and wet techniques (acidic ambient chloride complexation and hydrogen peroxide oxidation). After treating OP waste salt with low-temperature pyrolysis (320 °C), acidic ferric chloride complexation (pH 2–3, 0.28% FeCl₃), and neutral hydrogen peroxide oxidation (5% H₂O₂), the NaCl in the OP salt residue was purified and recovered with a purity of 98.80%. In addition, the aromatic hydrocarbons in the pyrolysis residue generated iron chloride complexes containing –OH or –COOH in the acidic system, which hastened the dissociation of the NaCl from the organic matter on the surface of the wasted salt.

The large amount of natural aggregate and cement in concrete production caused the exhaustion of natural resources and environmental impacts. Replacing the natural aggregate and cement using alternative materials in concrete production is necessary. The study aims to present the mechanical properties and durability of high-performance concrete produced with high-volume ground granulated blast furnace slag (GGBFS) and river sand/sea sand blended (S-HPC). The concrete mixtures were designed with a constant ratio of river sand and sea sand blending at 60:40 and various GGBFS content as partial cement replacement of 30%, 50%, and 70%. The mechanical strength and durability properties were observed up to 365 days of curing age. According to the findings, the S-HPC presented a good compressive strength achievement in a range of 73.2–83.9 MPa and UPV value of 4662–4860 m/s at 365 days of curing age. The washed sea sand concrete mixture presented a higher compressive strength and better durability performance than non-washed sea sand. Incorporating with GGBFS into S-HPC by up to 50% significantly improved concrete samples' mechanical performance, durability, and microstructure. Using GGBFS reduced the current records and delayed the initiation corrosion time of concrete samples.

The presence of impurities from raw materials directly affects the crystal shape control, process, and product performance of high-strength α-hemihydrate gypsum (α-HH,α-CaSO₄•0.5H₂O) from industrial by-product phosphogypsum (PG). In this work, effect of sodium fluoride on the crystal regulation of high-strength α-HH using calcium sulphate dihydrate(DH,CaSO₄•2H₂O) and PG as raw materials were investigated, respectively. The results showed that 0.6–1.8 wt% sodium fluoride can transform some α-HH crystals from fine needle shape to aggregate plate shape by changing the crystallinity, crystal habit and crystal diameter of α-HH. In the presence of 0.1 wt% citric acid and 0.6–1.8 wt% sodium fluoride, short hexagon-prism α-HH crystals can be obtained from DH or PG, sodium fluoride improved the content of α-HH in dehydration products, altered the dehydration and phase transition peak temperatures, transformed the crystallinity and crystal growth habit along the c-axis by the selectively chemisorption of F⁻, Na⁺ and citrate ions on the end surface of α-HH. With 0.1 wt% citric acid and 1.8 wt% sodium fluoride addition, the compressive strength of α-HH from DH and PG reached 59.8 MPa and 54 MPa, respectively, which were 54.3 MPa and 54.0 MPa higher than the blank samples.

The use of waste activated sludge (WAS) as a biocatalyst to produce polyhydroxyalkanoates (PHA) from waste streams may help promote the beneficial use of WAS for low-carbon, sustainable wastewater treatment. However, it remains unclear which types of substrates can be used for efficient PHA production, and how the PHA production can be maximized. This study aimed to assess the substrate versatility of mixed microbial cultures (MMCs) constructed from WAS by enriching PHA-accumulating bacteria using an aerobic dynamic discharge (ADD) process fed with acetate. Twelve different substrates, including organic acids, saccharides, and alcohols, were selected as the test substrates. In single-batch assays, the highest PHA production (583–680 mg/L) was achieved using butyrate, acetate, and pyruvate. In fed-batch assays, > 30 wt% PHA content was achieved using acetate, butyrate, propionate, lactate, and ethanol, with the highest content (60.3 wt%) using acetate. These results indicate that acetate-fed MMC by the ADD process could efficiently produce PHA from volatile fatty acids, lactate, pyruvate, and ethanol. Polyhydroxybutyrate was preferentially produced from acetate, butyrate, pyruvate, lactate, and ethanol, whereas polyhydroxyvalerate was notably produced from propionate. The results suggest that PHA can be efficiently produced from a wide range of substrates using MMCs enriched on a single substrate.