CaCO3 Content Research Articles

Study on the Permeability and Mechanical Properties of Sandy Soil Under Carbon Fiber-Based Urease Mineralization

In recent years, soil solidification by EICP method is a green and environmentally friendly foundation treatment technology that has become popular in the field of geotechnical engineering. Compared with the traditional chemical induction method and the MICP method, the EICP method is not easily restricted by environmental factors associated with engineering geological problems and is green and environmentally friendly with lower cost. In this paper, a study was carried out to improve the seepage-mechanical properties of sandy soils by the EICP method. First, soybean urease solution extraction and its performance optimization methods were explored. Tests were conducted to compare urease extraction and detect activity. The activity of urease was 7.1% higher in deionized water than Laoshan mineral water. Second, the EICP grouting mineralization test was performed by using the carbon fiber reinforcement method. The CaCO3 content, unconfined compressive strength, porosity, permeability and other indicators of the sandy soil were systematically analyzed, and microscopic tests were conducted. The test results showed that after carbon fibers were added to the sand, the mineralization effect of EICP led to the precipitation of CaCO3 that adhered to the surfaces of sand grains and fibers and filled and cemented the pores between sand grains, which improved the integrity of the spatial structure and formed a stable solid sand-fiber monolithic composite structure. When the carbon fiber content was 1.2%, all aspects of performance were optimum. The above test results showed that the carbon fiber-based EICP mineralization method could effectively inhibit the brittle failure and improve the permeability and mechanical properties of sandy soil. This method has good application prospects and development potential for use in engineering geology.

Impacts of Soil Management and Sustainable Plant Protection Strategies on Soil Biodiversity in a Sangiovese Vineyard

Vine growing is one of the most economically important sectors of Mediterranean agriculture, but its cultivation practices are highly detrimental to the environment and the associated biota. The application of both natural products inducing endogenous plant defense mechanisms and natural soil management systems represents a potential solution for the preservation and improvement of soil health and biodiversity. The Life Green Grapes project aimed at evaluating the effects of different natural and sustainable vine protection strategies and soil management on vineyard edaphic communities. Soil TOC, TN, C:N ratio, CaCO3 content and pH were measured. Microbial communities (bacteria and fungi) were characterized through NGS, while nematodes and microarthropods were isolated and identified. Obtained data highlighted a relationshipbetween bacteria, fungi and nematodes with soil chemistry, and an effect of the different soil management on the single and total edaphic communities. Network analysis evidenced a positive effect of the application of sustainable soil managements on the relationships among the different investigated soil trophic levels, suggesting that more natural soil managements allow a better interaction between soil organisms. In conclusion, this work confirms the importance of the application of sustainable and natural soil management practices in agricultural ecosystems, with the aim of conserving and improving soil biodiversity.

Effect of pH, Carbonate and Clay Content on Magnesium Measurement Methods on Hungarian Soils

More exact information on soil nutrient management is crucial due to environmental protection, nature conservation, decreasing sources for mining, general precaution, etc. Soil magnesium (Mg) analytical methods of potassium chloride (KCl), Mehlich 3 (M3), water (WA) and cobalt hexamine (CoHex) extractions are compared with an elemental analysis and X-ray fluorescence (XRF) analysis. The ratio of the available to the total Mg content was calculated and compared on the whole dataset. The results showed that the linear regressions between all the pairs of Mg content measurement methods were significant. The linear relationship between the KCl and CoHex methods has the highest determination coefficient (R2 = 0.96), followed by WA–M3 (R2 = 0.68), M3–CoHex (R2 = 0.66) and M3–KCl (R2 = 0.60). The M3 solution demonstrated a greater capacity for extracting Mg from the soil. The second part is the analysis of the influence of CaCO3, pH, soil texture and clay content on the measurable magnesium content of soils. It was established that the extraction methods, the soil and the classification method of the soil properties affect the evaluation. These results may help through the nutrient replenishment and the melioration of soils. These results can help the examination of mineral nutrients, especially the Mg uptake.

Isolation, Identification, and Carbonate Mineralization Characteristics of a Newly Carbonic Anhydrase-Producing Strain.

Carbonic anhydrase-producing microorganisms can rely on their metabolism for carbon sequestration and carbonate precipitation, which is a relatively effective mode among the known microbially induced carbonate precipitation (MICP) methods. A newly carbonic anhydrase-producing strain was isolated from soil samples. 16S rDNA gene sequencing showed this strain had 99.18% sequence identity to Chryseobacterium gambrini. Various culture parameters (temperature, pH, rotational speed, inoculum size, and metal ions) were optimized for optimal microbial growth and CA activities. Optimal culture conditions were as follows: temperature of 30°C, pH 6-7, rotational speed 150rpm, and inoculum size 1%. It was observed that Co2+ and Mn2+ can improve CA activity with optimal concentrations of 0.02mM and 0.01mM, respectively. Furthermore, the introduction of CO2 for 15min daily leads to a 36% increase in the final production of biotic CaCO3, reaching 2.884g/L. Characterization of the mineralization precipitates was conducted to reveal the mechanism of the carbonic anhydrase-producing bacterium. Lastly, an analysis of the crystalline species and content of the biogenic CaCO3 was performed to lay the groundwork for future crystalline adjustments and to offer technical support for the application of the calcium method.

Ionic Liquid-Assisted Production of Biochar with High Cu2+ Removal Efficiency: Effect of Pyrolysis Temperature and CaCO3 Content in Biomass

Ionic Liquid-Assisted Production of Biochar with High Cu2+ Removal Efficiency: Effect of Pyrolysis Temperature and CaCO3 Content in Biomass

Preparation of cellulose-PCC fibre hybrids: Use as filler in polypropylene (PP) composites

Abstract Polymer composite materials find application in various life sectors such as packaging, lightweight construction and the fabrication of medical devices. Functional fillers like mineral colloids, synthetic and natural fibres enable a precise tailoring of the mechanical properties of the resulting compounds. Precipitated calcium carbonate (CaCO3, PCC) has proven to be a special popular mineral polymer filler. From economic and ecologic reasons, it is desirable to increase filler contents in polymers while maintaining material strength. To achieve this, the present work has developed a hybrid filler system which is based on carboxymethylated, fibrillated cellulose fibres. CaCO3 is precipitated onto the fibres in a single step twin-screw extrusion process by the co-precipitation method. This process ensures a strong, permanent interaction between the fibres and the mineral particles, which enables CaCO3 contents in the filler of up to 68 wt.-%. The resulting hybrid fillers were compounded with polypropylene (PP) in a powder or paste state with filler contents between 5 wt.-% and 20 wt.-%. The resulting composites show an increase in the zero-shear viscosity and, in the event of sufficient network formation, a marked increase in stiffness was observed.

Gas CO2 foaming and intermixing in portland cement paste to sequester CO2

In this study, concentrated CO2 gas was used to create foamed cement paste, and concentrated CO2 gas was intermixed in fresh cement paste to produce regular cement paste materials that were not foamed. The potential of both methods to form CaCO3 from calcium ions that would form Ca(OH)2 was investigated. After curing the materials for different ages, the Ca(OH)2 and CaCO3 contents were measured using thermogravimetric analysis; the large void size distributions, dynamic modulus, and compressive strength were tested and compared against Control (no gas added), and N2 foamed and N2 intermixed specimens. A 10% increase in dynamic modulus and compressive strength was measured in CO2 foamed specimens compared to N2 foamed specimens. The increase in mechanical properties was the result of both a narrow void diameter distribution and CaCO3 formation in place of Ca(OH)2. The CO2 foamed cement generation method shows the potential to sequester 0.06 ton of CO2 for every ton of cement which is a CO2 emission reduction of 7.0% of the CO2 production associated with cement production. For the CO2 intermixing method, the void content, compressive strength, and dynamic modulus results were consistent between the Control and CO2 intermixed specimens while the N2 intermixed specimens showed a decrease in compressive strength and dynamic modulus. The CO2 intermixing method showed potential to sequester 0.04 ton of CO2 for every ton of cement or a 4.7% CO2 emission reduction of the total CO2 production associated with cement manufacturing. The reported CO2 emissions are not based on life cycle assessment and do not account for emissions associated with CO2 collection, transportation, and intermixing. The present paper does not investigate the mechanisms of hydration under CO2 intermixing.

An Accurate Approach for Predicting Soil Quality Based on Machine Learning in Drylands

Nowadays, machine learning (ML) is a useful technology due to its high accuracy in constructing non-linear models and algorithms that can adapt to the complexity and diversity of data. Thus, the current work aimed to predict the soil quality index (SQI) from extensive soil data, achieving high accuracy with the artificial neural networks (ANN) model. However, the efficiency of ANN depends on the accuracy of the data that is prepared for training. For this purpose, MATLAB programming language was used to enable the calculation, classification, and compilation of the results into databases within a few minutes. The proposed MATLAB program was highly efficient, accurate, and quick in calculating soil big data for training the machine compared with traditional methods. The database contains 306 vector sets, 80% of them are used for training and the remaining 20% are reserved for testing. The optimal model obtained comprises one hidden layer with 250 neurons and one output layer with a sigmoid function. The ANN achieved a high coefficient of determination (R2) values for SQI estimation, with around 0.97 and 0.98 for training and testing, respectively. The results indicate that 36.93% of the total soil samples belonged to the very high quality class (C1). In contrast, the high quality (C2), moderate quality (C3), low quality (C4), and very low quality (C5) classes accounted for 10.46%, 31.37%, 20.92%, and 0.33% of the samples, respectively. The high contents of CaCO3, pH, sodium saturation, salinity, and clay content were identified as limiting factors in certain areas. The results of this study indicated high accuracy of soil quality assessment using physical, chemical, and fertility soil features in regression analysis with ANN. This method, which is suitable for arid zones, enhances agricultural productivity and decision-making by identifying critical soil quality categories and constraints.

The effect of gamma rays and stearic acid on calcium carbonate and its impact on the properties of epoxy-based composites

Abstract The purpose of this research is to produce composites of epoxy resin and calcium carbonate (EP/CaCO3) and investigate how treating the CaCO3 filler with stearic acid and gamma radiation affects the properties of the epoxy composites, enhancing their suitability for a range of applications. The CaCO3 powder was subjected to stearic acid treatment and later exposed to γ-radiation at various doses namely (10, 20 and 30 kGy), Different weight percentages of untreated and treated CaCO3 powder were added to epoxy resin (EP) to create EP/CaCO3 composites loaded with varying amounts of CaCO3 filler (5 %, 10 %, 20 %, 30 %, and 40 %). The influence of both stearic acid treatment and different doses of gamma radiation on CaCO3 was investigated. The composites were subjected to characterization of various properties including mechanical (splitting tensile strength, impact strength), thermal (TGA and dimensional thermal analysis) as well as morphological SEM examination. The analysis’ findings demonstrated that the stearic acid monolayer functions as a coupling agent in the EP matrix and can coat CaCO3 particles efficiently. The modification of CaCO3 by stearic acid and exposure to 30 kGy of gamma radiation shows a notable improvement in thermal stability and mechanical qualities for the epoxy composites loaded with various CaCO3 concentrations.

Magnetic treatment as a suppressive method for CaCO3 scale deposition in hard waters in the presence of air bubbles

Calcium carbonate (CaCO3) scale deposition in hard water is a common problem affecting the performance and efficiency of various industrial applications such as water heating systems and pipelines. The aim of this study was to investigate the effectiveness of magnetic treatment as a suppressive method for CaCO3 scale deposition in hard water in the presence of air bubbles. A series of experiments were carried out using a laboratory-scale setup. The different CaCO3 concentrations (100 mg/L, 500 mg/L and 1000 mg/L) were considered. The hard water samples according to the various water circulation times (10, 20 and 30 min) were pumped with the flow rate of 50 L/h and passed through the region of the magnetic lines and air bubbles. A neodymium magnet (NdFeB-NB12) with a non-uniform magnetic flux density of 0.2 T on the inner walls and 0.05 T at the center was used. The CaCO3 particles deposition rate was measured using turbidity amount. The results demonstrated that the magnetic treatment significantly reduced CaCO3 deposition in hard waters in the presence in air bubbles. Turbidity changed from 0.3 NTU to 0.65 NTU at the CaCO3 concentration of 100 mg/L. It changed from 0.5 NTU to 2.25 NTU at the CaCO3 concentration 500 mg/L. Moreover, in CaCO3 concentration 1000 mg/L turbidity altered from 0.8 NTU to 3 NTU over circulation time 30 min. The simultaneous presence of magnetic fields and air bubbles reduced the amount of CaCO3 scale deposition and increased the nucleation in the bulk of the water. Aeration-based magnetic treatment is a promising alternative to chemical-based methods and an eco-friendly approach for hard waters treatment.

Effect of fibre‐reinforced microbial‐induced calcite precipitation on the mechanical properties of coastal soil

AbstractCoastal erosion is a global environmental concern, threatening infrastructure, human livelihoods and ecosystems. Recently, microbial‐induced calcite precipitation (MICP) has emerged as a promising ground improvement technique. The present study examined the effects of adding three different fibre reinforcements, namely carbon, basalt and polypropylene, on the physical and mechanical properties of coastal soil through MICP. The fibre content used was 0.20%, 0.40% and 0.60% of soil weight. A comprehensive biotreatment investigation was conducted using Sporosarcina pasteurii (S. pasteurii) in a 0.5 molar cementation solution. The samples prepared for this study had aspect ratios of 2:1 and 1:1. These samples were subjected to biotreatment, consisting of a 24‐h cycle for 9 and 18 days. Unconfined compressive strength (UCS), split tensile strength (STS) and ultrasonic pulse velocity (UPV) tests were conducted on the biotreated samples to evaluate the effect of fibre reinforcement on the mechanical properties of the biotreated samples. The amount of calcite precipitation, scanning electron microscope (SEM) and energy dispersive X‐ray spectroscopy (EDS) were used to interpret biocementation. Results suggest that adding fibres to the MICP process enhances the mechanical properties of coastal soil. The optimum fibre content for carbon and basalt fibre was 0.40%, whereas, for polypropylene, it stood at 0.20%. The maximum UCS, STS, UPV and average CaCO3 were observed in a basalt fibre‐reinforced biotreated sample with a fibre content of 0.40%, subjected to 18‐day biotreatment. Conversely, the sample without fibre‐reinforcement, biotreated for 9 days, exhibited the lowest values for these parameters. Samples subjected to 18 days of treatment have higher values of UCS, STS, UPV and CaCO3 content than 9‐day‐treated soil samples. SEM revealed the presence of CaCO3 precipitates on the surfaces of soil grains and their contact points, and the EDS spectrum corroborated this observation.

Pengaruh suhu, waktu perendaman, dan inhibitor alami terhadap laju korosi pada pipa tembaga di lingkungan asam HCL 0,1 N

Background: A pipe is a cylindrical casing used to convey liquid or gas fluid. Methods: In this study, we experimented with creating a composite with an HDPE resin matrix, while its filler is CaCO3 with compositions of 0, 4, and 7 (per one hundred of resin). Finding: Based on standards in its production, pipes are typically based on their nominal diameter, usually having a fixed outside diameter (OD) value while their thickness uses the term schedule, which varies in value. Meanwhile, the filler is another component evenly distributed within the matrix, playing a crucial role in strengthening the combination between the matrix and the filler. The purpose of this study is to determine the influence of the filler on its mechanical properties for its application in HDPE pipes. In previous research, CaCO3 compositions were varied at 0; 10; 20; 30; 40; and 50. Conclusion: From the test results (Tensile and Elongation), it is concluded that increasing the CaCO3 content in the sample affects the tensile value, decreasing it further.

Effects of microbially induced calcite precipitation on static liquefaction behavior of a gold tailings sand

Loose tailings are susceptible to static liquefaction during which they lose a substantial amount of their strength. This study examines a sustainable technique known as Microbially-Induced Calcite Precipitation (MICP) to improve the static liquefaction resistance of gold mine silty sand tailings. These materials were enriched with Sporosarcina pasteurii, consolidated in a direct simple shearing apparatus, and subjected to several injections of a cementation solution. Calcified tailings were then sheared under constant-volume and constant vertical stress conditions to evaluate their undrained and drained shearing behaviors. Results showed that bio-mineralization can prevent the occurrence of static liquefaction in tailings by reducing their contraction tendency. This is demonstrated by the strong strain-hardening behaviors of the treated tailings specimens compared to the strain-softening and undrained strength loss in specimens of the untreated tailings. Substantial increases in the tailings undrained and drained shear strengths (by up to 30 - 50 kPa), improvements (by up to 5 MPa) in their tangent moduli, and more than 5° rise in their friction angles are observed in the direct simple shear tests following MICP-treatment. The critical state line of tailings is also found to be steeper and shifted to denser void ratios following MICP treatment. These changes reduce liquefaction susceptibility of tailings and enhance their resistance against static liquefaction. Post-treatment acid dissolution further indicates that CaCO3 contents of about 4% to 11% precipitated in the treated specimens. This amount decreases with increasing specimens void ratio. Changes in the microstructural fabric of the cemented tailings particles are also characterized using scanning electron microscopic (SEM) images and X-ray diffraction (XRD) analyses.

Pengaruh penambahan CaCo3 terhadap mekanikal properti pada pembuatan pipa HDPE

Background: A pipe is a cylindrical conduit used for conveying fluids-liquids or gases. The purpose of this research is to determine the influence of fillers on its mechanical properties for application in HDPE pipes. Previous studies have been conducted with varying compositions of CaCO3: 0, 10, 20, 30, 40, and 50. Methods: In this study, I experimented by creating composites with an HDPE resin matrix while the filler was CaCO3 with compositions of 0, 4, and 7 (per one hundred resin). Finding: Based on standards in its production, pipes are usually based on their nominal diameter, typically having a fixed outside diameter (OD) while their thickness uses the term schedule which has varying values. Meanwhile, the filler is another component evenly distributed within the matrix, playing a crucial role in strengthening the combination between the matrix and the filler. Conclusion: From the test results (Tensile and Elongation), it is concluded that increasing the CaCO3 content in the sample affects the tensile value, decreasing it.

Semi‐Quantification of the Calcium Carbonate in Marine Sediments by Visible and Near‐Infrared Diffuse Reflectance Spectroscopy

AbstractAs one of the most widespread components in marine sediments, calcium carbonate (CaCO3) plays a crucial role in the global carbon cycle and climate changes. To efficiently semi‐quantify the CaCO3 concentration, a more effective, non‐destructive, economic, and accurate technique is required. Diffuse reflectance spectroscopy (DRS) has been widely used for the detection and quantification of minerals but has been less studied for CaCO3. This study synthesized a series of samples with well‐determined content of CaCO3 to analyze the visible and near‐infrared DRS characteristics. Results show that the intensity of the second derivative of Kubelka‐Munk (K‐M) remission functions of the DRS spectra at 2,340 nm (I2340) is linearly correlated with the CaCO3 content. Then, the new proxy I2340 was applied for marine sediments from the Pacific Ocean with known CaCO3 concentrations determined previously by chemical methods, and the robustness of the I2340 as the proxy for CaCO3 concentration was attested.

Analyzing the Impact of Storm ‘Daniel’ and Subsequent Flooding on Thessaly’s Soil Chemistry through Causal Inference

Storm ‘Daniel’ caused the most severe flood phenomenon that Greece has ever experienced, with thousands of hectares of farmland submerged for days. This led to sediment deposition in the inundated areas, which significantly altered the chemical properties of the soil, as revealed by extensive soil sampling and laboratory analysis. The causal relationships between the soil chemical properties and sediment deposition were extracted using the DirectLiNGAM algorithm. The results of the causality analysis showed that the sediment deposition affected the CaCO3 concentration in the soil. Also, causal relationships were identified between CaCO3 and the available phosphorus (P-Olsen), as well as those between the sediment deposit depth and available manganese. The quantified relationships between the soil variables were then used to generate data using a Multiple Linear Perceptron (MLP) regressor for various levels of deposit depth (0, 5, 10, 15, 20, 25, and 30 cm). Then, linear regression equations were fitted across the different levels of deposit depth to determine the effect of the deposit depth on CaCO3, P, and Mn. The results revealed quadratic equations for CaCO3, P, and Mn as follows: 0.001XCaCO32 + 0.08XCaCO3 + 6.42, 0.004XP2 − 0.26XP + 12.29, and 0.003XMn2 − 0.08XMn + 22.47, respectively. The statistical analysis indicated that corn growing in soils with a sediment over 10 cm requires a 31.8% increase in the P rate to prevent yield decline. Additional notifications regarding cropping strategies in the near future are also discussed.

Comparison of Land Suitability Methods for Estimating Quantity of Maize Yield in Calcareous Soils

ABSTRACT The modeling and assessment of land suitability is a prerequisite for land development and is one of the necessary needs to prevent land degradation. Maize is considered to be the most important crop, covering significant areas of agricultural lands in widely different regions across the world. However, not all available lands are equally suitable for maize cultivation. The main objective of this study was focused on identifying the potentials as well as the limitations of studied calcareous soils for maize cultivation in north Khuzestan province, Iran. Furthermore, some parametric models and multi-criteria land suitability evaluation methods for physical, chemical, fertility, and climatic factors (MC-LSE) were compared in estimating the maize yield. The required samples were taken from 23 land units by excavating control pedons. The necessary physicochemical parameters were then measured in the laboratory. The land indices were calculated by using different methods. The maize potential production of the investigated area was then obtained based on the climatic conditions. Finally, using land indices and the potential production, the estimated yield for each land unit was calculated and compared with the actual yield data. The obtained results indicated that the main limiting factors for maize yield in the region are high soil CaCO3 content, high salinity, high alkalinity and low organic matter. A comparison of predicted and actual yield indicated that the corrected square root method is accurate enough to assess land suitability and to estimate the maize yield with a high coefficient of determination (0.91) and a low RMSE value.

Contribution of the Soil Macro- and Microstructure to Organic Matter Stabilisation in Natural and Post-Mining/Industrial Soils under Temperate Climatic Conditions

The soil organic matter (SOM) content and stability in natural gypsum soils and mining/industrial soils were compared to check the effects of selected soil properties (mainly macro- and microstructure) on SOM stability and determine whether the old brownfield soils regardless of being highly polluted with trace metals could store high amounts of SOM. The mining/industrial soils were 50–400 years old and so had been left sufficiently long for full self-restoration. Despite having very different origins, both natural and brownfield soils stored similar amounts of SOM and had similar pH values, calcium carbonate contents, and textures but differed in SOM stabilisation, which was expressed by higher C/N ratios, lower aggregate water resistance index, lower dehydrogenase activity, and greater areas of undecomposed or slightly decomposed plant residues in mining/industrial soils compared to gypsum ones. However, the differences diminished with time, and in the oldest (150–400 years) brownfield soils, these parameters were similar to those in natural soils. Multiple regression analysis indicated that under the study conditions, SOM amounts, besides CaCO3 contents and dehydrogenase activity were also strongly affected by porosity and microaggregation. In the research we showed the role of degraded soils in the sustainable use of the environment.

Effects of simulated groundwater solutions with different Ca2+ to Mg2+ concentration ratios on asymmetric electrodeposition in concrete

Electrodeposition is an emerging and unique method for the repair of concrete cracks, in particular, with great potential for the repair of aged asymmetric subsurface structures. However, the effect of groundwater solutions on the effectiveness of concrete repair by electrodeposition is not clear. Using an asymmetric electrodeposition repair device, this paper investigates the effect of simulated groundwater solutions with different Mg2+ to Ca2+ concentration ratios on the effectiveness of electric field-induced ettringite for repairing concrete cracks. Results show that the simulated groundwater solution has a negligible effect on the macroscopic repair effect on the electrolyte solution side, but allows a certain amount of Mg(OH)2 and CaCO3 precipitation to be generated on the simulated solution side. Meanwhile, compared with the deionized water group, the permeability coefficient is reduced from 2.05×10−6 cm/s to less than 7.65×10−7 cm/s at the repair age of 14 days. The total impedance is enhanced from 1322 KΩ to more than 1658 KΩ, with the lower the Mg2+ to Ca2+ concentration ratios, the lower the permeability coefficient and the higher the total impedance. Microstructure analysis suggests that as the concentration ratio of Mg2+ to Ca2+ decreases, the content of loose porous Mg(OH)2 decreases and the content of dense CaCO3 increases on the simulated solution side. Moreover, the size of the Mg(OH)2 particles on the simulated solution side, becomes larger and the amount of production decreases while the CaCO3 increases and changes from aragonite to calcite type.

Determining Effective Threshold Range of Image Pixel Values for Municipal Waste-Contaminated Clay

Currently, more attention has been given to the study of the microstructure of contaminated clay, while few studies have focused on the analysis of SEM images of clay from a threshold perspective. The purpose of this paper was to determine the threshold range of image pixel values for municipal waste-contaminated clay by observing and processing SEM images of municipal waste-contaminated clay under different seepage depths and concentrations. In this study, municipal waste-contaminated clay samples were obtained at different depths in a column test exhibiting different CaCO3 and CH3COOH concentrations, imaged through SEM and subjected to binarization. Three steps for determining the pixel threshold value of the SEM images were described, including preprocessing and binarizing the SEM images in Image Pro Plus 6.0 (IPP) and morphological processing by the Pores (Particles) and Cracks Analysis System V2.3 (PCAS). The apparent void ratio of contaminated clay and the fractal dimension of clay particles were applied as evaluation parameters. The determined effective threshold range of the image pixel values of municipal waste-contaminated clay was 110–140. The accuracy of this method was verified in three aspects: the relationship between the threshold value and the apparent void ratio, the variation in pore blockage with seepage depth, and the characteristics of the compaction factor with seepage depth and pollutant concentration.