Waste Soil Research Articles

Spatial variability characterization of clayey waste soils and its impact on probabilistic stability assessment of a landfill slope

Spatial variability characterization of clayey waste soils and its impact on probabilistic stability assessment of a landfill slope

Predicting Cyanide Degradability and Destruction Using Artificial Neural Networks: A Case Study in West Azerbaijan, Iran”

ABSTRACT The presence of cyanide compounds in soil can lead to the formation and evaporation of hydrogen cyanide (HCN), while some of these compounds can undergo conversion by microorganisms present in the soil. However, high concentrations of cyanide can be toxic to soil microorganisms. During the gold extraction of mines, sodium cyanide (NaCN) solution is commonly used which results in a significant amount of cyanide waste that is regarded as an environmental pollutant. Previous studies have proposed physical, chemical, and biological methods to eliminate cyanide, but they have not achieved optimal efficiency. Unfortunately, the potential of artificial intelligence (AI) in this domain has been overlooked. Artificial Neural Network (ANN) models, specifically the multilayer perceptron (MLP) and simple linear regression, can significantly enhance and expedite the cyanide remediation process due to their remarkable predictive capabilities. In this study, an MLP and simple linear regression were employed to predict the biodegradation procedures of cyanide in soil. The study focused on cyanide waste generated by gold extraction factories and utilized environmental factors such as initial waste cyanide concentration, pH, soil and environmental temperature, humidity, chloride concentration, alkaline, electrical conductivity, precipitation, evaporation intensity, cyanide concentration, and initial pH as input data for the artificial neural network. The results of the MLP model revealed that electrical conductivity is the most influential factor in predicting the cyanide rate and initial pH of the waste soil. Conversely, the results of the simple linear regression indicated that the variables with the greatest impact on cyanide concentration are electrical conductivity (0.881), time (0.862), and alkalinity (0.724). By leveraging AI techniques such as ANN, this study demonstrates the potential for improved cyanide remediation. The integration of environmental factors and predictive models can contribute to more effective strategies for addressing cyanide pollution in soil.

Comparison of Mechanical Properties of Compacted Waste Soil from Open Dumping Area and Clay Soil for Future Development

Estimating the mechanical properties of soil samples involves analysing properties such as shear strength, density, and moisture content. It is important to use consistent and standardized testing methods, as well as to normalize the data to the same volume or weight, when comparing soil mechanical properties. Evaluating multiple properties will provide a more complete understanding of the differences between soils. Additionally, it is crucial to consider factors such as soil composition, history, and location when comparing soil properties. The main purpose of this paper is to compare the two types of soil which are waste soil and clay soil. Waste soil tends to have weak structure due to the multiple content of waste while clay soil is weak because of water absorption of in the clay structure. These two properties will have implications in terms of its mechanical properties. The experimental works that was conducted in this research are direct shear stress, density, water content and compressive strength. Clay soils tend to be less dense due to their fine-grained nature and the small size of their particles. Waste soil, on the other hand, can vary in density and can often be less dense than natural soils due to the presence of large void spaces. The water content in clay soils can significantly affect its shear strength, as excessive water can weaken the cohesive forces between the clay particles. In waste soil, the moisture content can affect the density and compaction of the soil, which can impact its stability. The expected outcome from this research is the conclusion of the mechanical properties for both types of soil.

Parametric study of brick manufacturing by replacing clay with landfill waste soil

Parametric study of brick manufacturing by replacing clay with landfill waste soil

Parametric study of bricks manufacturing by replacing claywith landfill waste soil

Parametric study of bricks manufacturing by replacing claywith landfill waste soil

Bacillus thuringiensis VP4: A potential keratinase producer isolated from poultry waste soils of Himachal Pradesh

Keratinase enzymes are protein hydrolyzing enzymes belonging to the serine hydrolase group and act specifically on keratin proteins to degrade them. The current study was conducted to isolate best keratinase producer bacterial strains. Four Bacillus species (B. cereus PP1- OP748781, B. cereus JP1- OP748782, B. cereus TP1- OP748783 and B. thuringiensis VP4- OP420549), were isolated from the poultry farms of Himachal Pradesh. These strains were evaluated for keratinase production by using chicken feathers in shake flask culture. Among four isolates, Bacillus thuringiensis VP4 showed highest enzymatic activity 343 U/ml. The molecular weight of the keratinase was observed 45 KDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimization of enzyme production was done with isolate Bacillus thuringiensis VP4 at various parameters such as temperature, pH and effect of metal ions. The maximum keratinase production was observed at 35°C temperature and pH 10.0. The isolated strain Bacillus thuringiensis VP4 might be used to produce poultry compost through degradation of chicken feathers and poultry waste in short time which may also be helpful for farmers and overcoming environmental pollution.

Upcycling of the industrial waste as a sustainable source of axenic fungal strain (Aspergillus oryzae) for scale up enzymatic production with kinetic analysis and Box–Behnken design application

Abstract The utilization of industrial waste for valuable product synthesis is essential for mitigating the environmental impact of climate change and managing waste disposal challenges. Industrial waste is always a big challenge for global warming. In this study, a novel fungus strain was isolated, and identified as Aspergillus oryzae (AKMS), from the oily surface of industrial effluent from an oil industry. Submerged fermentation was exploited to achieve maximum lipases production. A sequence of batch experiments was performed, altering five primary components: sucrose (for carbon), molasses (constituting nutrient mix), yeast extract (as nitrogen supply), sunflower oil (used as an activating agent), and Tween-80 (functioning as an emulsifying agent). These elements are recognized for their substantial impact on the proliferation of microorganisms and, consequently, the synthesis of lipases. The maximum lipase activity for each ingredient was determined, with sucrose showing 2.4 ± 0.539 U/mL at 0.15 g/L, molasses at 1.499 ± 0.291 U/mL at 0.25 g/L, Tween 80 % at 3.33 ± 0.484 U/mL at 0.25 g/L, sunflower oil at 7.49 ± 0.282 U/mL at 1 % v/v, and yeast extract at 4.165 ± 0.841 U/mL at 0.075 % v/v. The optimization of the lipase production and activity was done by using RSM (Box–Behnken design) with the 41st run yielding the maximum activity of 9 U/mL, while the 25th run showed the minimum activity of 4 U/mL, enzyme estimation (U/mL and U/g), glucose (g/L), and dry cell mass estimation (g/L) were monitored up to 120 h of fermentation in a custom-made fermenter with a working volume of 7 L. The highest production of extracellular and intracellular lipases (27.4 ± 0.378 U/mL and 25.4 ± 0.208 U/g, respectively) was observed at the 40 h interval, with the highest value of dry cell mass at 20 g/L. Glucose concentration initially peaked and subsequently decreased over time. A. oryzae exhibited the capability to produce triacyl glycerol acyl hydrolases, demonstrating its potential significance in biotechnological applications. These novel findings shed light on the efficient utilization of oil industry waste soil for isolation of microorganism for sustainable lipase production and highlight the biotechnological promise of the novel isolated fungal strain, which was reported first time in this study.

Carbon reduction potential of a rain garden: A cradle-to-grave life cycle carbon footprint assessment

With emphasis on constructing low-carbon cities, the renovation of old communities highlights the importance of renewing rainwater management facilities. Rain garden is an exceptional Nature-based Solution for rainwater management. When applying them to renovate old communities, the carbon footprint should be considered. This study focused on renovating facilities in the Greater Bay Area and utilized the Energy Expert platform to calculate rain garden carbon footprint with the Life Cycle Assessment. The carbon reduction benefits during the operation were estimated. This study accounting the life cycle carbon footprint of the 5455 m2 rain garden was 1117.42 tCO2e. The carbon footprint contribution, from highest to lowest was the end-of-life phase, materials production phase, construction phase, use and maintenance phase. Regarding carbon emission inventory, waste soil landfill, fertilizer acquisition, and waste soil recycling ranked high. Transportation also accounted for a remarkable carbon emission. The rain garden showed great potential for climate change mitigation, with a total and net carbon reduction of 1927.41 and 809.99 tCO2e, respectively. To reduce the carbon footprint of the rain garden, we should focus on waste soil treatment and transportation. Recommendations included increasing waste soil recycling, in situ recycling and green transportation.

Compressive strength of fly ash based geopolymer utilizing waste completely decomposed granite

An attempt to recycle construction waste soils in southern cities of China was presented in this study, where completely decomposed granite (CDG) was utilized to replace fly ash in the production of environment-friendly low-carbon geopolymers. Five crucial parameters were identified and incorporated into the experimental design using the Taguchi method, including fine and gravel particle content of CDG, fly ash content, water-binder ratio, and curing temperature. Test results demonstrate that the newly formulated geopolymer can achieve a compressive strength of up to 14 MPa with a relatively high usage of CDG. The strength initially increases and then stabilizes with an increase in fine particle content. However, no significant relationship is observed between the compressive strength and gravel particle content. Higher curing temperatures and greater fly ash content lead to increased strength, while the strength initially decreases and then slightly increases with changes in the water-binder ratio. To examine the significance of these factors, Analysis of variance (ANOVA) were conducted and a correlation heatmap was drawn, revealing the following order of significance: curing temperature > fly ash content > water-binder ratio > fine particle content > gravel particle content. Furthermore, a robust strength prediction model was modified through multiple regression analysis. Another two additional groups of tests were performed to validate the proposed model, demonstrating the model's strong performance, particularly for curing ages beyond 14 days.

An Evaluation of Cesium Removal from Simulated Radioactive Contaminated Soil with a Magnetized Zeolite Derived from Anthracite

The magnetized zeolite with an optimized conversion rate of 53% can be readily synthesized from industrial anthracite using a water-based method. The highly porous structure of ferromagnetism zeolite demonstrates robust magnetic properties with a magnetite content of 12–15%, satisfying adsorbent separation and recycling through magnetic cylinder rotating and vibrating separation. A cesium adsorption and removal efficiency as high as 99.92% with a corresponding adsorbent recovery ratio of up to 96.36% can be achieved for the simulated cesium-contaminated soil with a water content of 20% and a cesium content of 1% with an adsorbent-to-contaminated soil ratio of 1:2. Adsorption and magnetic separation technology with magnetized zeolite synthesized from anthracite exhibited a high cesium removal rate and zeolite recovery ratio, demonstrating promising application potential in treating radioactive waste soils and robust and economically viable engineering feasibility.

Effect of Polymeric Agent on the Strength and Water Stability of Cement-Stabilized Construction Waste Soil

Due to the large output of construction waste soils, it has become an enormous challenge for human society and the ecological environment. The purpose of this paper is to discuss the possibility of using a stabilized waste soil in road engineering. Cement and polymer stabilizers were added to the waste soil, and the effect of the stabilizer on the strength and water stability of the stabilized soil was studied. The structure and morphology of the specimens were analyzed using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM). The results show that the unconfined compressive strength increases by 25.0% and the 28-day water stability coefficient, K increases by 59.6% after the addition of the stabilizer. The XRD curve shows that the addition of the new stabilizer does not produce a new characteristic peak, but the diffraction peak strength of some minerals can be improved. SEM shows that the surface of stabilized soil particles is covered by materials, and the particles show obvious agglomeration, forming a network structure, which improves the strength and water stability of the soil.

Reuse of engineering waste soil and recycled fine aggregate to manufacture eco-friendly unfired clay bricks: Experimental assessment, data-driven modeling and environmental friendliness evaluation

In order to explore the possible application of engineering waste soil (EWS) and recycled fine aggregate (RFA) in cement-based unfired clay bricks (CUCB), this paper utilizes the orthogonal experiment to investigate the combined utilization of EWS and RFA to fabricate eco-friendly CUCB. The study employs an L9 (34) orthogonal table with four factors and three levels for designing mix proportions. The factors include the ratios of water-to-cement (w/c), cement-to-EWS (c/e), RFA-to-EWS (r/e) and additive content. CUCB were tested for density, compressive strength, and flexural strength; and the impact of each factor on these properties was analyzed. The test results reveal that the eco-friendly CUCB exhibit lightweight characteristics and desirable mechanical properties. The ratio of flexural strength-to-compressive strength for eco-friendly CUCB ranges from 0.23 to 0.28, indicating that eco-friendly CUCB have good toughness. Data-driven models were developed to construct the relationships between target properties (i.e., density, compressive strength, and flexural strength) and four factors. The optimal mix proportion for physical and mechanical properties was determined to be w/c= 0.55, c/e = 0.3, r/e = 0.4 and additive content= 10%, with predicted compressive and flexural strengths of 19.68 MPa and 5.19 MPa, respectively. In addition, Scanning Electron Microscope (SEM) was performed to figure out the strength enhancement mechanism of eco-friendly CUCB with varying mix proportions. Environmental friendliness evaluation shows that the optimal mix pro-portion is more environmentally friendly to fabricate CUCB from the perspective of strength-normalized carbon footprint and energy consumption. Using large quantity of cement cannot increase the compressive strength and only acts as filler in the microstructure of eco-friendly CUCB.

The design of ternary all-solid-waste binder for solidified soil and the mechanical properties, mechanism and environmental benefits of CGF solidified soil

Utilization of industrial solid waste to develop binder and solidified waste soil, which can achieve ‘waste control by waste’. Based on the alkali-activated mechanism and interaction mechanism of the binder-soil particles-water, the component distribution ratio design method of ternary all-solid-waste binder for solidified soil was constructed. The CGF all-solid-waste alkali-activated binders (CGF binders) are composed of general industrial solid waste, with which calcium carbide slag (CCR) as alkali activator, ground granulated blast furnace slag (GGBS) and fly ash (FA) as high and low-activity pozzolanic material respectively. Macro and microscopic tests were performed to reveal the mechanical properties and solidification mechanism as well as quantitatively evaluate the environmental and economic benefits of CGF solidified pure clay, pure silt, and pure sand (CGF solidified soils). The results revealed that the strength of CGF solidified soils was significantly affected by the alkali activator content and the activity of pozzolanic materials, and the strength of partially CGF solidified soils were higher than cement solidified soils under the same conditions. The relationship between binder-soil particles-water, viz., the alkali-activated reaction between binder and water, along with the pozzolanic reaction between the alkali activator and the clay particles jointly determined the strength and strength growth rate of the solidified soil. The strength of the optimal CGF solidified soils were 1.38–2.30 times higher than cement solidified soils, however, the carbon emission per unit strength and cost per unit strength of the cement solidified soil were 71.43–125.02 times and 3.53–5.88 times higher than the optimal CGF solidified soils, respectively. The findings can provide a reference for the design and development of solid waste-based binders suitable for solidified soils.

Solidification Treatment of Wastewater and Waste Soil Generated during Binhai Reclamation: A Study on Mechanical Properties and Resource Utilization

Coastal reclamation projects generate an accumulation of wastewater and waste soil, resulting in highly saturated soft soil. Presently, there is a scarcity of research regarding the lightweight solidification and three-dimensional mechanical properties of these soils. Additionally, there is a dearth of specialized models for stabilizing soils containing wastewater using lightweight solidification technology, and pertinent engineering solutions are lacking. By introducing solidifying agents and foaming agents to treat wastewater in soft fill soil, a novel type of solidified lightweight material is produced, imparting strength. This study investigates its three-dimensional mechanical properties. During triaxial tests with equal stress (σ3) and equal b values, the softening of the curve noticeably diminished at b = 0.25. In the plane strain test, cohesion increased by 10.7% compared to the traditional triaxial tests, and the internal friction angle increased by 11%. Subsequently, a three-dimensional Cambridge model was established. At elevated confining pressures, the corrected curve closely approximated the test curve, demonstrating a minimum model accuracy of approximately 96% at a confining pressure of 20 KPa. These findings offer valuable numerical references and a theoretical foundation for the efficient utilization of wastewater and waste soil.

Effect of microbiology handout on Amylolytic bacteria and Cellulolytic bacteria from vegetable waste soil on students' cognitive abilities

The scientific literacy framework in PISA 2015 includes context, competence, attitudes and knowledge. Knowledge is closely related to students' cognitive abilities. Analysis of needs in the class of 2020 Biology at the State University of Malang shows that 93.8% of students' knowledge about amylolytic and cellulolytic bacteria in vegetable waste disposal soil is relatively low. One factor is that there are no teaching materials related to this material. The research aims to determine the effectiveness and practicality of handouts in improving students' cognitive abilities. This research method is quasi-experimental with a nonrandomized pretest-posttest control group design—implementation in the control and ex-perimental classes by giving a pretest and posttest. The increase in posttest scores compared to the learning outcome scores for both classes was analyzed using the T-test to compare learning outcomes based on the N-gain score. The results of the unpaired t-test analysis stated that the cognitive abilities of students in the experimental class using handout were higher than those in the control class using PowerPoint—comparison value p-value (0.046) < α (0.05). The conclusion is that the handouts are practical and effective in improving students' cognitive abilities. Students can find out the existence of bacteria that play a role in the degradation process of starch and cellulose so that students can protect the environment and not throw away rubbish, which causes an imbalance in the soil ecosystem.Abstrak Kerangka kerja literasi sains dalam PISA 2015 meliputi konteks, kompetensi, sikap, dan pengetahuan. Pengetahuan erat hubungannya dengan kemampuan kogintif mahasiswa. Analisis kebutuhan di biologi angkatan 2020 Universitas Negeri Malang menunjukkan pengetahuan 93,8% mahasiswa tentang bakteri amilolitik dan bakteri selulolitik pada tanah pembuangan sampah sayur tergolong rendah. Salah satu faktornya adalah tidak ada bahan ajar terkait materi tersebut. Tujuan dari penelitian untuk mengetahui keefektifan dan kepraktisan handout dalam meningkatkan kemampuan kognitif mahasiswa. Metode penelitian ini kuasi eksperimen dengan desain nonrandomized pretest-posttest control group. Implementasi pada kelas kontrol dan kelas eksperimenn dengan diberikan pretest dan posttest. Peningkatan nilai posttest dibandingkan untuk nilai hasil belajar kedua kelas dan dianalisis dengan uji T untuk membandingkan hasil belajar berdasarkan N-gain skor. Hasil analisis uji-t tak berpasangan menyatakan kemampuan kognitif mahasiswa kelas eksperimen menggunakan handout lebih tinggi dibandingkan kelas kontrol menggunakan Power Point. Nilai perbandingan p-value (0,046) < α (0,05). Kesimpulannya adalah handout praktis dan efektif meningkatkan kemampuan kognitif mahasiswa. Mahasiswa dapat mengetahui keberadaan bakteri yang berperan dalam proses degradasi amilum dan selulosa, sehingga mahasiswa dapat menjaga lingkungan, tidak membuang sampah yang menyebabkan ketidakseimbangan ekosistem tanah.

Evaluation of the Solidification of Radioactive Wastes Using Blast Furnace Slag as a Solidifying Agent.

The decommissioning process of nuclear power facilities renders hundreds of thousands of tons of various types of waste. Of these different waste types, the amount of concrete waste (CW) varies greatly depending on the type of facility, operating history, and regulation standards. From the previous decommissioning projects, CW was estimated to comprise 60-80 wt.% of the total weight of radioactive wastes. This represents a significant technical challenge to any decommissioning project. Furthermore, the disposal costs for the generated concrete wastes are a substantial part of the total budget for any decommissioning project. Thus, the development of technologies effective for the reduction and recycling of CW has become an urgent agenda globally. Blast furnace slag (BFS) is an industrial byproduct containing a sufficient amount (higher than 30%) of CaO and it can be used as a substitute for ordinary Portland cement (OPC). However, there have been few studies on the application of BFS for the treatment of radioactive waste from decommissioning processes. This study was conducted to evaluate the performance of the solidification agent using ground granulated BFS (SABFS) to pack radioactive wastes, such as the coarse aggregates of CW (CACW), waste soil (WS), and metal waste (MW). The analytical results indicated that the CaO content of the ground granulated BFS was 36.8% and it was confirmed that calcium silicate hydrate (CSH) could be activated as the precursor of the hydration reactions. In addition, the optimum water-to-binder ratio was determined to be 0.25 and Ca(OH)2 and CaSO4 were found to be the most effective alkaline and sulfate activators for improving the compressive strength of the SABFS. The maximum packing capacities of the SABFS were determined to be 9 and 13 wt.% for WC and WM, respectively, when the content of CW was fixed at 50 wt.%. The results of the leaching tests using SABFS containing radioactive wastes contaminated with Co, Cs, and Sr indicated that their leachability indices met the acceptance level for disposal. Consequently, the SABFS can be used as a solidifying agent for the safe disposal of radioactive waste.

Preparation of environmental remediation material based on manganese-slag and sewage sludge as a strategy for remediation of cadmium pollution

Both manganese-slag and sewage sludge are typical solid wastes, but their utilization is limited. Based on the soil properties, the abovementioned pollutants were combined with Broussonetia papyrifera to treat soil cadmium (Cd) pollution. Three materials (sewage sludge-derived biochar (SSB), Mn-SSB, and Mn-slag (Slag)) were prepared using oxygen-limited pyrolysis technology with Slag and sewage sludge, and the effects of the three materials on the phytoremediation of Cd-polluted soil were investigated. All three materials had distinct morphological characteristics, good functional group structure, specific surface area, and porosity. The adsorption and leaching experiments in the solution indicated that the three materials could not only directly absorb Cd2+ but also release nutrients, such as nitrogen and phosphorus. The soil pH increased significantly (p < 0.05) with the addition of the above environmental remediation materials. Furthermore, the contents of soil organic carbon, available nitrogen, and available phosphorus in soil increased significantly, whereas the electrical conductivity of the soil decreased significantly (p < 0.05). During remediation of Cd-polluted soil by integrating the above materials with B. papyrifera, Slag significantly increased the B. papyrifera biomass, but the effects of SSB and Mn-SSB were not significant. SSB, Mn-SSB, and Slag significantly increased the protein content of B. papyrifera leaves, with Mn-SSB having the most significant effect (p < 0.05). The applications of SSB, Mn-SSB, and Slag reduced the malondialdehyde content and increased the activities of superoxide dismutase and peroxidase, reducing the damage to B. papyrifera. Mn-SSB significantly reduced the Cd content in the roots, stems, and leaves of B. papyrifera, and SSB and Slag promoted Cd enrichment in B. papyrifera. This study realized the comprehensive utilization of Mn-slag and sewage sludge and established a recycling system from solid waste to the treatment of waste soil.

Remediation Opportunities for Arsenic-Contaminated Gold Mine Waste

Arsenic (As)-contaminated gold mine waste is a global problem and poses a significant risk to the ecosystem and community (e.g., carcinogenic, toxicity). Arsenic concentrations of 77,000 mg/kg and 22,000 mg/kg in mine waste have been reported for Canada and Australia, respectively. Research is investigating environmentally sustainable techniques to remediate As-rich mine waste. Biological techniques involving plants (phytoremediation) and soil amendments have been studied to bioaccumulate As from soil (phytoextraction) or stabilise As in the rhizosphere (phytostabilisation). Identified plant species for phytoremediation are predominately fern species, which are problematic for arid to semi-arid climates, typical of gold mining areas. There is a need to identify native plant species that are compatible with arid to semi-arid climates. Arsenic is toxic to plants; therefore, it is vital to assess soil amendments and their ability to reduce toxicity, enhance plant growth, and improve soil conditions. The effectiveness of a soil-amending phytoremediation technique is dependent on soil properties, geochemical background, and As concentrations/speciation; hence, it is vital to use field soil. There is a lack of studies involving mine waste soil collected from the field. Future research is needed to design soil-amending phytoremediation techniques with site-specific mine waste soil and native plant species.

Vermicompost Combined with Soil Conditioner Improves the Ecosystem Multifunctionality in Saline-Alkali Land

Addressing the challenges posed by Saline-Alkali land holds significant promise for optimizing agricultural resources and fostering sustainable agricultural development in affected areas. This study explores the efficacy of coal-based solid waste soil conditioner and vermicompost as mixed-component soil amendments in varying proportions. Through comprehensive field experiments, we investigate the impact of these amendments on soil physicochemical properties, microbial diversity, and the growth of L. chinensis, a grass species native to saline areas. Our findings reveal that the application of vermicompost-based soil amendments effectively reduced soil conductivity and led to noteworthy improvements in the pH of Saline-Alkali soil. Moreover, these amendments demonstrated a marked capacity to enhance soil organic matter and available nutrients, most notably available phosphorus. Concurrently, the introduced soil amendments exhibited a positive influence on soil microbial diversity. A correlation analysis underscores the pivotal roles of soil pH and organic matter in shifting soil microbial communities. In response to amendments, L. chinensis exhibited varying degrees of growth enhancement, with biomass increments ranging from 6.37% to 19.91%. In summary, vermicompost and soil conditioner can improve Saline-Alkali land by supplementing organic matter and effective nutrients, improving pH and conductivity, and regulating microbial community, so as to realize the restoration and improvement of Saline-Alkali land; the greatest improvement was achieved with soil conditioner and vermicompost application rates of 30,000 kg·ha−1 and 15,000 kg·ha−1, respectively. Our results provide robust support for advocating for the integration of vermicompost-based soil amendments in Saline-Alkali land management strategies.

Improving the Characteristics of Less Active Geopolymer Binders Utilizing Ground Granulated Blast-Furnace Slag under Different Curing Conditions

In the current study, the influence of substitution of ground granulated blast-furnace slag (GGBFS) on the characteristics of less active geopolymer binders, including pumice and the waste material produced during the washing process of sand in aggregate industries (waste soil), is investigated. The aforementioned materials were examined individually and in hybrid form. In the hybrid mixes, less-active materials (pumice and the waste soil) were replaced with GGBFS at levels of 25%, 50%, and 75%. The evaluated properties consisted of compressive strength, modulus of rupture, sorptivity, rapid chloride ion migration coefficient, and the content of water absorption. Moreover, the effects of different curing conditions on the properties were investigated. The results indicate that partial replacement of the waste soil and pumice with GGBFS leads to enhanced durability and mechanical characteristics owing to the higher reactivity of GGBFS. The mixture denoted as P25S75 (with 75% GGBFS and 25% pumice) exhibited the best durability properties, surpassing even the S100 mixture (with 100% GGBFS). Substituting the waste soil with GGBFS had a greater enhancing effect compared to the mixtures containing the pumice mixes.