Waste Soil Research Articles

Reinforcement of a Soft Soil Foundation Using Waste Soil Prefabricated Piles: A Case Study

Reinforcement of a Soft Soil Foundation Using Waste Soil Prefabricated Piles: A Case Study

Bioremediation of Kalamkari Dye using Novel Bacterium Bacillus Inaquosorum Isolated from Textile Contaminated Waste Soil of Srikalahasti, A. P

Bioremediation of Kalamkari Dye using Novel Bacterium Bacillus Inaquosorum Isolated from Textile Contaminated Waste Soil of Srikalahasti, A. P

Investigation of mechanical and thermal performances and masonry quality for new raw soil-based insulating hollow bricks

ABSTRACT The development of raw soil-based insulating hollow bricks (RSIHB) provides a promising way for improving the efficiency of building energy conversation and resource utilization of construction waste soil. In this paper, the response surface method (RSM) was adopted to study the effect of multifactor on mechanical and thermal performances of modified raw soil-based samples. The results indicate that the thermal conductivity is significantly affected by the interactions between molding pressure and mixture moisture content, as well as between mixture moisture content and cement admixture. Thus, the optimal mix ratio was determined by the RSM-based regression model. The assessment based on numerical simulation demonstrates that the middle wall ribs immensely improve the stress concentration. The porous structure elongates the path of heat flow conduction, effectively enhancing the thermal resistance of the brick. In addition, bonding strength tests manifest that the mortar consistency should be within 60–80 mm for construction and plastering of the new raw soil-based insulating hollow brick. The research results have strong theoretical significance and practical value for recycling of construction waste and provide a reference for actual production and construction.

An innovative sustainable solution: Recycling shield-discharge waste soil as fine aggregate to produce eco-friendly geopolymer-based flowable backfill materials

The disposal of Shield-Discharge Waste Soil (SDWS) is substantial, yet their recycling rate remains low, necessitating the exploration of new recycling methods for effective waste management. This study examines the potential use of SDWS as a fine aggregate in the production of Controlled Low-Strength Material (CLSM), incorporating slag and fly ash as precursors. Key properties such as strength, flowability, setting time, microstructure, chemical composition, CO2 emissions, energy consumption, and cost were assessed and analyzed. Additionally, the environmental impact and material-related strategies were discussed. The results reveal that the developed CLSM exhibits competitive performance, with compressive strengths ranging from 2.830 MPa to 4.121 MPa, achieving over 1.0 MPa strength within 24 hours. The material demonstrates high flowability, exceeding 200 mm within 30 minutes, and has a setting time between 2.10 and 4.23 hours, offering advantages in both setting time and early strength. SDWS contributes to extending the coagulation process and enhancing the flowability. Optimal strength is observed when SDWS constitutes approximately 30 % of the binders or when the alkali equivalent is around 7 %. Compared to traditional cement-based CLSMs, incorporating SDWS results in reduced CO2 emissions and lower energy consumption. When considering savings from reduced waste disposal costs, the overall material cost remains competitive. Furthermore, higher SDWS content leads to enhanced environmental benefits, and it is recommended to keep the alkali equivalent below 7 % for optimal performance. In conclusion, the developed CLSM presents significant potential for wide-scale applications and offers a sustainable solution for recycling SDWS.

EarthWorks: Zero waste 3D printed earthen formwork for shape-optimized, reinforced concrete construction

Rapid global urbanization is driving governments and builders to seek paradigm-shifting technologies to speed the construction of housing and infrastructure at a low economic and carbon cost. Here, we present a novel method for fabricating materially efficient, shape-optimized, code-compliant, reinforced concrete structures cast in directly recyclable 3D printed earth formwork, hereby referred to as EarthWorks. This research demonstrates the potential of zero waste, circular formwork that can be manufactured with construction waste soils directly on site. Methods are described for formwork design and toolpathing that accounts for hydrostatic pressure, conventional reinforcement, high accuracy connections, and the fabrication of complex, 3D-shaped geometry with continuous extrusion. In addition, the building design and performance potential of the EarthWorks method are assessed and compared to existing additive formwork technologies from a carbon perspective. Case studies are fabricated demonstrating cast-in-place, tilt-up, and on-site prefab methods to produce bespoke columns, beams, and frames designed to California building code.

Digital Image Analysis on Structure of Constructional Waste Soil Cemented by Microorganisms

Digital Image Analysis on Structure of Constructional Waste Soil Cemented by Microorganisms

Assessment of growth, and ion uptake of plant species, Conocarpus erectus and Dodonaea viscosa, on industrial solid waste

Present study assessed the growth of two plant species and ion uptake by them grown on different proportion of industrial solid waste and garden soil. The industrial waste having high concentration of chemicals were used with garden soil at different proportion i.e. 0% (T0), 5% (T1), 10% (T2), 15% (T3) and 20% (T4). Two species namely Conocarpus erectus (alien plant) and Dodonaea viscosa (indigenous) were used as test plants in pot study. Different parameters including growth, physiology, and anatomy of plants and concentration of cations (Na+, K+, Ca2+, and Mg2+) in the plant shoot and root were measured at different time duration (initial, 1st, 2nd, 3rd and 4th month). The key objective of the study was to use these plants to establish their plantations on the barren lands where industrial solid wastes were being disposed of. C. erectus showed better growth than D. viscosa, as well as more uptake of ions. A significant increase in plant growth was observed in fourth month in T1, where plant height reached 24.5% and 46% for C. erectus and D. viscosa, respectively. At harvest, in C. erectus, no significant difference in the fresh (65–78 g) and dry weight (24–30 g) of the shoot was observed across treatments compared to the control. In D. viscosa, at the time of harvest, the fresh and dry weights of the root and shoot showed a strong, significantly decreasing pattern across T1, T2, and T3, leading to the death of the plant at T3 and T4. Further, optimum ratio of waste soil to garden soil was found as 10:90 and 20:80 to establish the plantations of D. viscosa and C. erectus, respectively in areas where such solid waste from industries are disposed. Findings can be used for the restoration of such solid waste for the sustainable management of industrial areas and their associated ecosystems.

Isolation and Characterization of Staphylococcus saprophyticus from Textile Industry Soil for Decolorization of Crystal Violet Dye

Textile dyes are an important class of synthetic organic compounds and are, therefore, common industrial pollutants. They are produced in large scale and may enter the environment during production or later on during fiber dying. Thus, there is a need for developing treatment methods that were more effective in eliminating dyes from textile waste soil as its source. Staphylococcus saprophyticus was isolated from soil of a textile plant and selected as the most active dye degrader of 11 isolates. The important parameters including temperature, pH, carbon and nitrogen source on crystal violet decolorization were investigated. Under the optimum conditions, dye decolorization (92.35%) was successfully achieved within 120 h. at 30°C, pH 8 with sucrose and beef extract as the energy source.

Effects of Leaching Agents on Pb and Cd Immobilization in Battery Waste Contaminated Soils Amended with Bare and Stabilized Zero-Valent Iron Nanoparticles

This study compared the effectiveness of bare zero-valent iron nanoparticles (B-nZVI) and starch-stabilized zero-valent iron nanoparticles (S-nZVI) in immobilizing Pb and Cd from lead-acid battery waste soils. Both B-nZVI and S-nZVI were prepared in almost identical manner using the technique of reducing ferric chloride with sodium borohydride. X-ray diffraction (XRD) and dynamic light scattering (DLS) analyses confirmed that polydisperse B-nZVI and S-nZVI were synthesized. XRD and DLS analyses showed that B-nZVI and S-nZVI had different surface properties. To assess the immobilization capability of B-nZVI and S-nZVI, a composite soil sample was collected from an automobile lead-acid battery waste dumpsite. The soil sample had a pH of 3.85 and Pb and Cd levels of 16,674 mg/kg and 41 mg/kg, respectively. Single extraction procedures using 0.01M CaCl2, 0.1 M HCl, and 0.05 M EDTA were used to simulate phytoavailable Pb and Cd in the soil studied. Batch immobilization analysis showed that Cd was mobile in the control but immobile in B-nZVI and S-nZVI treated soils. Pb was however not immobile in either the control or treated soils. The mobility of Pb however decreased with increasing doses of S-nZVI and 0.003 g of S-nZVI was needed to make Pb completely immobile in soil. Batch immobilization also showed that S-nZVI was 1.8-2.49 times more efficient in immobilizing Pb than B-nZVI. Simulated phytoavailability of Pb was in the order of EDTA > HCl > CaCl2 > H2O while simulated photoavailable Cd was in the order of HCl > EDTA > H2O > CaCl2.

Investigation and Utilization of Alkali-Activated Grouting Materials Incorporating Engineering Waste Soil and Fly Ash/Slag

The alkali-activated composites technique is a promising method for the in situ preparation of cavity filling/grouting materials from engineering waste soil. To investigate the feasibility of engineering waste soil utilization by the alkali activation process, the macroscopic and microscopic properties of the fly ash/slag-based alkali-activated composites, after solidification/stabilization (S/S) with sandy clay excavated at Baishitang Station of Shenzhen Metro, were studied. The unconfined compressive strength (UCS) test was conducted to evaluate the S/S effect of alkali-activated composites. The results show that the optimum quality ratio of slag and fly ash correspond to 7:3, the modulus of alkaline activator to 1.3, and the alkalinity of alkaline activator to 10%. The alkali-activated composite’s strength under these parameters can reach 45.25 MPa at 3 days, 49.85 MPa at 7 days, and 62.33 MPa at 28 days. A maximum 3-day UCS of 21.71 MPa, 75% of the 28-day UCS, was achieved by an engineering waste soil and alkali-activated composites mass ratio of 5:5, slaked lime content of 4.5%, and a water-to-solid ratio of 0.26, and it can also meet the required fluidity and setting time for construction well. Fluidity is primarily affected by the soil-to-binder ratio, which decreases as the ratio decreases, while the water-to-solid ratio increases fluidity. Slaked lime has minimal impact on fluidity. The setting time is mainly influenced by the soil-to-binder ratio, followed by slaked lime content and water-to-solid ratio, with setting time shortening as the soil-to-binder ratio and slaked lime content increase, and lengthening as the water-to-solid ratio increases. Through Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) tests, microscopic analysis showed that loose granular units are firmly cemented by alkali-activated composites. Based on the results of on-site grouting tests in karst caves, the alkali-activated grout materials reached a strength of 5.2 MPa 28 days after filling, which is 162.5% of the strength of cement grouting material, satisfying most of the requirements for cavity filling in Shenzhen.

Development of sustainable geopolymer with excavation soil powder as precursor: Cementitious properties and thermal-activated modification

One of the focal and challenging issues in the research on sustainable building materials pertains to the recycling of construction excavation soil. This paper developed the sustainable geopolymer containing waste soil powder (WSP) from the construction excavation soil as a precursor. The WSP contains a large number of inert components, while more active components were generated in 600–1200 °C thermoactivated WSP. Substituting WSP for metakaolin (MK) negatively impacts the alkali-activated polymerization reaction of MK-based geopolymer paste, but the geopolymer paste containing thermal-activated WSP has better micro-properties than the geopolymer paste containing un-treated WSP. Mixing WSP raises the drying shrinkage of geopolymer mortar, while the drying shrinkage is reduced with the addition of 600–800 °C thermal-activated WSP. The maximum drying shrinkage of geopolymer mortar with 75 % 800°C-activated WSP is 36.6 % lower than that of plain geopolymer mortar. Substituting WSP for MK causes a reduction in the strength and permeability resistance of geopolymer mortar. At the constant replacement rate of WSP, the geopolymer mortar containing thermal-activated WSP has better strength and permeability resistance than the geopolymer mortar containing un-treated WSP. At 100 % replacement rate of WSP, the sustainable geopolymer mortar made with 1200 °C thermal-activated WSP still has good compressive strength (36.38 MPa). The waste soil-concrete powder (WSPC) also serves as an alternative precursor for sustainable geopolymer materials. Substituting WSPC for 100 % MK in geopolymer is feasible, and the geopolymer made with 800 °C thermal-activated WSPC is much greater than the geopolymer made with un-treated WSPC. Optimizing WSP/WSPC substitution rate and thermal activation temperature can achieve the sustainable geopolymer materials with good performance.

Soil-cement columns for high-rise buildings: design–testing–construction–monitoring: A case study of green solution in Vietnam

Soil cement columns (SCCs) are commonly used to reinforce soft ground to support roads and railway embankments, or to withstand horizontal pressure for deep excavations. This study presents another application of SCCs as load-bearing foundations for high-rise building projects. SCCs with a diameter of 800 mm, length of 10 m, cement content of 350 kg/m3, and an unconfined compressive strength (UCS) of 3.6 MPa were applied. In this study, five single columns and one group constituting two columns were constructed, and core drilling and axial static load tests were conducted. The test results indicated that the SCC could achieve a load of 1,650 kN for a single pile and 3,300 kN for the group constituting two columns. In total, 1,123 columns were designed and constructed for this project. Compared with conventional reinforced concrete pile methods, a project using SCC could save 30 construction days and 20% of the total cost. Moreover, SCC can be considered a green and environmentally friendly foundation solution because it does not use concrete or steel materials and does not produce waste soil.

GC-MS analysis of hospital waste soil and isolation of antimicrobial agent producing bacteria

The current study, deals with the GC-Mass analysis of soil and antibiosis activity of soil bacteria, isolated from district hospital at Kabir Chaura, Varanasi, India. Standard serial dilution plate procedures were used to isolate the bacteria. Gram staining was used to identify the isolates morphologically. Strain KC14 was Gram-negative and all other isolates were Gram-positive. Isolated bacteria were tested against six human pathogens viz., Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Shigella flexneri and Bacillus subtilis. Primary and secondary screening were done by perpendicular streaking and seed overlay techniques. Based on the results most potential isolates were selected for tertiary screening. The GC-MS of soil samples revealed some major medical pollutants such as para-hydroxy acetanilide, 2-methyl-5-nitro-imidazole and 2-acetoxybenzoic acid. The KC14 isolate was chosen for further studies after demonstrating positive results against S. aureus with a maximum antagonistic activity of 17.3 ± 0.5 zone of inhibition. The molecular identification of KC14 isolate was determined by using 16S rRNA sequencing. The obtained nucleotide sequences were subjected to BLASTN in NCBI, and found similar to the available sequence of Acinetobacter junii. The nucleotide sequences have been deposited in GenBank with accession no. OP265396. The active compound was partially purified by ethyl acetate and tested its activity against S. aureus. This study defines the composition of hospital waste soil and identified a Gram-negative bacterium producing antibacterial activity against important human pathogens.

Mechanical and microstructural properties of one-part geopolymer-solidified soil attacked by Na2SO4

In the construction of traffic engineering, a large amount of waste soils was generated. These soils have poor engineering properties, cannot be used as subgrade fill, so they were solidified treatment, commonly used cement curing agent have adverse effects on the environment. One-part geopolymer (OPG), as a green and new type of soil stabilizer, not only provides a new idea for the solidification of engineering waste, but also offers an effective way for the disposal of industrial solid waste, and reduces the consumption of cement. In order to evaluate the durability of geopolymer solidified soil, in this paper, with fly ash (FA) and ground granulated blast furnace slag (GGBS) as raw materials, solid NaOH and Na2SiO3 as solid alkali-activator to prepare OPG, which was used as a solidifier to solidify the waste dredged silt to produce one-part geopolymer-solidified soil (OPGSS). The variation patterns of mass, unconfined compression strength (UCS) and elasticity modulus of OPGSS with attack time under 0%, 5% and 10% Na2SO4 solutions were investigated. The changes in the phase composition, micro-morphology and pore size distribution of OPGSS were characterized by XRD, SEM-EDS and nuclear magnetic resonance (NMR). The results showed that: Under both 5% and 10% Na2SO4 solutions, the UCS of OPGSS decreased in two stages with attack time, and the number of large pores and total pores of OPGSS increased in two stages. The inflection points appeared on day 8 under 5% Na2SO4 solution; the inflection points appeared on day 5 under 10% Na2SO4 solution. This was mainly due to the expansion of corrosion products formed by OPGSS under Na2SO4 attack, which destroyed the microstructure of OPGSS and led to a reduction in the UCS of the OPGSS.

Development and performance evaluation of sustainable lightweight cement composites utilizing fly ash and waste soil

Development and performance evaluation of sustainable lightweight cement composites utilizing fly ash and waste soil

Preparation and properties of high blending phosphogypsum-desulfurization ash-waste soil based functional prefabricated autoclaved aerated concrete slabs

There is a huge stock of industrial solid waste piles such as phosphogypsum (PG), desulfurization ash (DA), and waste soil (WS) in China, and their utilization rate is insufficient. These have potential risk for environmental safety due to pollutants contained in them. In this study, after proportioning design, raw material pretreatment, bubble regulation and multi-temperature section maintenance process, successfully prepared a high blending solid waste based functional prefabricated autoclaved aerated concrete slabs (FPAS) with excellent functional performance, and the optimal ratio of each raw material is PG: WS: DA: cement: lime = 8:50:20:10:12, and the dry mass ratio is up to 75%, the compressive strength of the slabs is up to 5.2 MPa, the standard dry density is 606 kg/m3, the dry shrinkage value is 0.36 mm/m, and the post-freezing strength is 4.0 MPa, which is in line with the basic requirements in the standard “Autoclaved aerated concrete slabs” (GB/T15762), and at the same time, its fire-resistant integrity is qualified for 240 min, and the coefficient of thermal conductivity is 0.15w(m.k), airborne sound-weighted sound insulation is 46 dB, also can show different functional characteristics. In order to investigate the environmental safety of heavy metals (HMs) in the slabs, the simulation experiment of HMs leaching from outdoor stacking of slabs was carried out. The results show that the HMs in the slabs do not pose obvious risks to the natural environment and human body, but three of the characteristic HMs, Cr, Cd and Hg, have significant leaching patterns, which can be expressed by a second-order kinetic model. Finally, the life cycle assessment and cost analysis of the high blending PG-DA-WS based FPAS and the conventional aerated slabs were carried out. The main environmental damage category of the high blending PG-DA-WS based FPAS is land ecological risk, and it has obvious environmental and economic benefits compared with the conventional aerated slabs.

Soils in the current waste management system

This article is part of the dissertation research. In modern conditions of active construction, the volumes of excavated soil can amount to hundreds of thousands and millions of cubic meters, making up the bulk of waste generated in the process of engineering and economic activities. Such significant volumes of waste (in the form of soil) pose the challenge of making appropriate decisions about their subsequent disposal, reuse or disposal. To solve such issues, it is necessary to know the system of waste management, which is soil, and the current shortcomings in the principles of organization and functioning mechanisms of this system. The authors of the presented article analyzed the system for handling soils falling into the category of waste. In general, soils are complex multicomponent systems characterized by dynamic changes in composition, structure and properties. Taking into account the specifics of the object under study, the weakest aspects and controversial issues were identified in the analyzed regulatory and methodological materials. One of which is the very fact that soil is categorized as waste from a regulatory point of view. The article examines the contradictions in the definitions used in regulatory documents, the position of soils in the overall waste management system, as well as the procedure for establishing the hazard class of waste; Particular emphasis is placed on the need to use biotesting methods to confirm the V hazard class of waste. The article presents the generalized results of large-scale experimental studies by the team of authors, obtained when assessing the hazard class of waste soils, carried out for the purity of the experiment on soils under the conditions of modeling different in composition and level of pollution. Based on the results obtained, basic proposals have been formulated for improving approaches in the current system for handling soils that fall into the category of waste during engineering and economic, and, above all, engineering and construction activities.

Analysis of the Mechanical Properties of Cured Sludge by Alkaline Excitation of Phosphogypsum

Engineering slag is a green building material that meets the requirements of contemporary sustainable development, and the solidification technology of residue is particularly important in the practical engineering of resource utilization and environmental protection. In order to reuse the waste soil and industrial waste and reduce the construction cost, the stabilization effect of adding different contents of calcium oxide, blast furnace slag and phosphogypsum to the waste soil of a township road reconstruction project was studied. The unconfined compressive strength test of calcium oxide further clarified the solidification mechanism of residual soil and helped us to obtain the optimal curing ratio. The dry and wet cycle test simulated the influence of temperature and humidity changes on the appearance, quality, strength and water resistance in actual engineering. The experimental results show that the unconfined compressive strength of the sample reaches 1.273 MPa after 7 days of curing when the mixture of 4% calcium oxide (ratio to 100% plain soil) and 16% blast furnace slag (ratio to 100% plain soil) is mixed. When the three materials were mixed, the unconfined compressive strength of 4% calcium oxide (the ratio of 35% phosphogypsum and 65% plain soil) and 16% blast furnace slag (the ratio of 35% phosphogypsum and 65% plain soil) reached 1.670 MPa and 3.107 MPa at 7 and 28 days, respectively. The curing age has a significant promoting effect on the stability of loess. The dry and wet cycle test results conclude that the specimens have good durability and stability. The results of microstructure analysis shows that a large number of ettringite and C-S-H gel were formed in the gelling system, which not only makes the original soil more stable, but also acts as a part of filling pores, and the two work together to support the soil and improve the strength.

Assessment of Engineering Behavior and Water Resistance of Stabilized Waste Soils Used as Subgrade Filling Materials

Urban construction has generated substantial amounts of waste soils, impeding urban ecological development. With the aim of promoting waste recycling, waste soils possess a high potential for sustainable utilization in subgrade construction. However, these waste materials exhibit inadequate engineering properties and necessitate stabilization for an investigation into their long-term performance as subgrade filling materials. Initially, a thorough assessment and comparison were conducted to examine the key mechanical properties of lime- and cement-stabilized soils with mixed ratios (total stabilizer contents ranging from 2% to 8%). The results indicated that these soils met the requirements of subgrade materials except for the 2% lime-treated soil. Subsequently, to reveal the improvement in water resistance of stabilized waste soil (e.g., under conditions of rainfall or elevated groundwater table), the effects of soil densities and stabilizer contents on the disintegration characteristics were investigated using a range of disintegration tests. An evolutionary model for the disintegration ratio of stabilized soils was then developed to predict the process of disintegration breakage. This model facilitates the quantification of the lower disintegration rates and elevated disintegration time attributed to higher levels of compactness and stabilizer contents during a three-stage disintegration process. This enhances the understanding and evaluation of sustainable applications in stabilized waste soils used as subgrade filling materials.

Solidification of Radioactive Wastes Using Recycled Cement Originating from Decommissioned Nuclear-Energy Facilities

Hundreds of thousands of tons of waste are generated from decommissioned nuclear- power facilities, and it has become a critical global issue to secure technology for reducing and recycling this waste. Concrete waste (CW) is estimated to comprise 60–80% of the total waste, and concrete-waste powder (CWP) includes enough inorganic substances used as effective materials for waste treatment. Accordingly, it can be used to produce recycled cement (RC). This study aimed to evaluate the performance of a solidification agent manufactured using recycled cement (SRC) for the safe packing of radioactive wastes, such as coarse aggregates of CW, waste soil, and metal wastes originating from decommissioned nuclear facilities. The experimental results indicated that the most relevant incineration temperature of CWP for RC was 700 °C. The optimum water-to-binder ratio was determined to be 0.4, and the most relevant substitution ratio of ground granulated blast furnace slag for CWP was determined to be 15%. In addition, calcium silicate hydrate is the most effective hydration product for improving the compressive strength of SRC. The maximum packing capacities of the SRC for coarse aggregates, waste soil, and metal waste, which were simulated as radioactive wastes, were determined to be 30, 5, and 7 wt%, respectively. The results of leaching tests using SRC containing radioactive wastes contaminated with Co, Cs, and Sr indicated that their leachability indices met the acceptance level for disposal. Consequently, the RC composed of CWP can be used as a solidifying agent to safely dispose of radioactive wastes, such as coarse aggregates, waste soil, and metal waste.