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Apportionment of heavy metals in a soil–water-plant system via brick kiln emissions in heavily industrialized city of Pakistan
2022
Ahmad, Imran | Ahmad, Hamaad Raza | Farooqi, Zia Ur Rahman | Ṣābir, Muḥammad | Rizwan, Muhammad | Maqsood, Muhammad Aamer
One of the major environmental problems is the fast accumulation of brick kiln emissions near the peripheries of almost all urban centers. An enormous quantity of substandard coal, wood, rubber tires, or saw wood is used as fuel in these brick kilns, creating environmental pollution through carbon and heavy metals present in the emissions. The present study was designed to determine the distribution pattern of heavy metals in a soil–water-plant system under the influence of brick kiln emissions. Ash, soil (0–15 cm), water, and plant samples were collected from the adjacent areas of the brick kilns. Geo-accumulation index and contamination factors were used to assess the toxicity of metals to soil and plants. It was found that the concentrations of Cd in water, soil, coal, and plant samples were found in the range of 0.004–0.024 mg L⁻¹, 0.02–0.66, 0.002–0.042, and 0.06 to 0.07 mg kg⁻¹, respectively, while Pb concentration was found within the range of 0–0.08 mg L⁻¹, 0.30–8.60, 0.011–0, and 0.01–0.08 mg kg⁻¹ in water, soil, and plant samples, respectively. The concentration of Cd in brick kilns ash was in the range of 0–0.04 mg kg⁻¹ while Pb was found within the range of 0.01–0.05 mg kg⁻¹ for ash. Geo-accumulation index and contamination factor values for Cd were found higher suggesting proper pollution prevention measures to be implemented. Based on the results, it was concluded that Cd concentrations in soil, plants, and water samples were higher in the subject area due to brick kiln emissions and higher Cd concentrations in the fuel material.
Показать больше [+] Меньше [-]Synergistic effect on the performance of ash-based bricks with glass wastes and granite tailings along with strength prediction by adopting machine learning approach
2022
Praburanganathan, Selvaraj | Chithra, Sarangapani | Simha reddy, Yeddula Bharath
The study proposes a novel and sustainable method to appropriately utilize wastes from granite as well as glass industries in brick manufacturing. An ecofriendly and low-cost manufacturing process of ash-based bricks pertaining to the Indian standard codal provisions that can be adopted on the commercial scale is deliberated. The research also recommends the method for predicting the strength of the ash-based bricks using machine learning algorithms like random forests and decision trees. For positive synergy in the performance, both the granite tailings and glass waste must be used together. Using the granite tailings and glass waste together led to a significant reduction of 75% in the fly ash requirement without compromising the brick’s performance. The addition of the granite tailings and glass waste in the mix could increase the strength of the brick by 90.5% and 37.7%, respectively. Beyond 30% dosage of granite, tailings are not recommended as they may lead to the poor gradation of particles and weak bonding in the microstructure. The glass waste in the mixture should not be more than 15% as it causes the dilution of pozzolanic reactions thereby forming fewer hydrated compounds. Brick’s durability is known after exposing the specimens for 1 year to sewers and biogenic corrosion environment, marine environment, and saline soil environment, respectively. The inclusion of the industrial wastes significantly reduced the specimen damage in the extreme environmental conditions along with the least absorption rates. The dosage of ash, granite tailings, and glass waste has to be maintained around 15%, 30%, and 15%, respectively for attaining the optimum performance. Out of the generated machine learning algorithms, only random forests could be able to predict the values accurately with R² values at 0.90 and with comparatively lesser errors.
Показать больше [+] Меньше [-]Recycling of marble cutting waste additives in fired clay brick structure: a statistical approach to process parameters [Erratum: October 2022, v.29(47); p.71948]
2022
Erdogmus, Ertugrul | Yaras, Ali | Sutcu, Mucahit | Gencel, Osman
Within the scope of the present study, the marble cutting waste, which is an industrial waste of different sizes (< 75 µm and < 150 µm), was incorporated into the clay structure at various rates and a total of 36 series bricks were produced. The brick mixtures were prepared by the semi-dry molding method and the brick specimens were sintered for three temperatures (850 °C, 950 °C, and 1050 °C). The fired bricks containing marble cutting waste with a lower particle size (75 µm) have higher compressive strength. However, all samples produced can meet the relevant standard requirements in terms of compressive strength. Thermal conductivity decreased from 1.008 to 0.775 W/mK with the incorporation of marble cutting waste, a decrease of approximately 23.11%. The effects of grain size, firing temperature, and marble cutting waste concentration on the quadratic model were statistically determined by variance analysis (ANOVA). According to statistical findings, the order of importance of design factors for brick properties (except for compressive strength) is marble cutting waste > firing temperature > particle size. For compressive strength, the most dominant factor is amount of marble cutting waste, followed by particle size and firing temperature, respectively. Consequently, the results suggest that marble cutting waste does not need to be reduced to smaller particle sizes to improve the fired clay brick properties.
Показать больше [+] Меньше [-]Lignocellulosic materials as soil–cement brick reinforcement
2022
Sabino, Ticyane Pereira Freire | Coelho, Nayane Pereira Freire | Andrade, Nayhara Camila | Metzker, Stefânia Lima Oliveira | Viana, Queilla Santos | Mendes, Juliana Farinassi | Mendes, Rafael Farinassi
The need for environmental preservation requires civil engineering to reach new concepts and technical solutions aiming at the sustainability of its activities and products. In this context, this study aimed to evaluate the effect of using different types and percentages of vegetable particles on the physical, mechanical, and thermal properties of soil–cement bricks. Bamboo, rice husk, and coffee husk particles at 1.5 and 3% percentages and a control treatment not using the particle were evaluated. The chemical properties, shrinkage, compaction, consistency limits, and grain size were characterized for the soil; and the anatomical, chemical, and physical properties for the lignocellulosic particles. The bricks were produced using an automatic press and characterized after the curing process for density, water absorption, porosity, loss of mass by immersion, compressive strength, durability, and thermal conductivity. The increase in the lignocellulosic waste percentage caused a mechanical strength decrease and bricks’ porosity and water absorption increase. However, it caused a decrease in density and an enhancement in loss of mass and thermal insulation properties. The bricks produced with rice husk obtained the best results in terms of mechanical and thermal properties, and were still among the best treatments for physical properties, standing out among the lignocellulosic waste as an alternative raw material source for soil–cement brick production.
Показать больше [+] Меньше [-]Study on preparation of brick blocks by using construction waste and sludge
2022
Vaithiyasubramanian, Raguraman | Srinivasan, Deepasree | Kanagarajan, Arul Kumar
The demand for scarce raw material has been increased with rise of construction. An ideal raw material is clay, which is abundantly used in manufacturing bricks. The proposed study aims at making a brick blocks with clay-free materials. Therefore, instead of clay, waste additives such as sludge waste, construction and demolition waste, and fly-ash are used as a binding material. These additives would contribute a better performance and properties without altering the desired strength. Sewage sludge is an important component of sewage disposal, but it is also ruinous to the environment. Construction and demolition (C&D) debris are a rising source of waste utilization. The objective of the proposed work is to eliminate the natural resources like clay and utilization of waste additives effectively in making brick blocks. The mix proportions are maintained at 30% sludge with 3:2:2, 2:3:2, and 2:2:3 (fly ash: cement: C&D), similarly, 40% sludge with 1:3:2, 2:3:1, and 3:2:1 and 50% sludge with 2:1:2, 2:2:1, and 1.5:1.5:2. The physicochemical properties include density, water absorption, pH, shrinkage, plasticity index, and efflorescence, and leaching characteristics were analyzed. Mechanical properties include compressive strength and thermal conductivity; mineralogical and microstructural analysis and durability aspects were carried out. The presence of organic matter influences the overall property. The stress distribution was induced by porosity and attained a maximum strength of 14.5 N/mm². Durability was influenced by compaction and temperature. At high temperature, the particles are well compacted. The concentrations of heavy metals are immobilized. Based on the above, it can be practically implemented in structures as well as in hidden masonry works.
Показать больше [+] Меньше [-]Life cycle approach applied to the production of ceramic materials incorporated with ornamental stone wastes
2022
Barbosa, Márcio Zago | de Oliveira Dias, Josinaldo | Marvila, Markssuel Teixeira | de Azevedo, Afonso R. G.
The use of the ornamental stone wastes, such as the originated from granite or marble, has been the subject of technological studies that evaluated its application in ceramic and cement materials; however, some complementary assessments, such as its life cycle assessment, are still not well explored in the literature. Therefore, the objective of this study was to discuss the main environmental impacts related to the manufacture of ceramic specimens, comparing conventional production versus the production of specimens incorporated with ornamental stone wastes. For this, the life cycle assessment was conducted in accordance with ISO 14.040 and 14.044. For this research, the ornamental stone wastes from the municipality of Cachoeiro do Itapemirim–ES and clay from the municipality of Campos dos Goytacazes–RJ were used. The system was modeled, using the SimaPro 9.0 software and the Ecoinvent database 3.3, for the life cycle assessment of the ceramic specimens and the potentiality regarding the use of ornamental stone wastes in ceramic materials using alternative input energy for burning, contributing to the effectiveness of the solid wastes reuse by the ceramic industry. The evaluation identified that the ornamental stone wastes incorporated into the ceramic specimens had significant potential in reducing environmental impacts and that the alternative input energy in burning stage makes them even more relevant. The study points out as the main result, the reduction of 35.74% of the impacts related to the category of the emission of greenhouse gases, and scarcity of mineral resources, 14.83% reduction, when compared to specimens to conventional brick production and alternative brick production, which emphasizes that the ceramic materials with wastes contribute to the mitigation of impacts.
Показать больше [+] Меньше [-]Characteristics of Historical Underground Storage Sites of Capacitors Containing Polychlorinated Biphenyls
2022
Cui, Yong | Ning, Yuhang | Chen, Guo | Zhang, Lei | Wang, Xin | Cheng, Weiguo | Hou, Haimeng | Zhang, Chong | Wang, Jian
Historical underground storage sites for decommissioned capacitors containing polychlorinated biphenyls (PCBs) were import sources of high-concentration PCB contaminants. However, few studies have delved into the characteristics of these sites. We investigated the wastes and cleaned-up soil, soil PCB contamination, and potential risks of 16 underground PCB-capacitor storage sites in China. Among these sites, PCB leakage occurred at all the sites with direct burial (six sites) and brick structures (three sites) and at three out of the seven sites with cement structures. From each site, an average of 60.7 t of wastes and contaminated soil were cleaned up, and the contaminated soil accounted for an average of 65.5% of the total wastes. The maximum contents of total PCBs, 12 dioxin-like PCBs (DL-PCBs), and 7 indicator PCBs (ID-PCBs) in the soil samples of each site were 51–30,700 mg/kg, 1.1–379.7 mg/kg, and 2.3–10,340 mg/kg, respectively. The total PCB and PCB congener contents in soil showed clear short-range heterogeneity as differences of up to orders of magnitude were found within a short distance (e.g., 2 m). Based on the human health risk assessment model, the maximum risks of all the sites were above the acceptable risk level (10⁻⁶). More than a half of the samples within different sites showed higher risks as per calculations with total PCB contents than for calculations with DL-PCB contents, indicating that only focusing on DL-PCBs may underestimate the potential risks for PCB-capacitor storage sites.
Показать больше [+] Меньше [-]Experimental evaluation of the thermal performance of cool pavement materials in cold regions of China
2022
Ding, Wei | Feng, Wei | Zhen, Meng | Zhen, Qingjiang | Liu, Ying
The local thermal property evaluation of pavement materials has not received enough attention, making the implementation of cool material measures to alleviate the urban heat island difficult. This study aims to conduct a control experiment on cool pavement bricks selection from the local market. The surface temperature difference and change characteristics of 28 bricks with different physical properties (i.e. colour, thickness, size and internal structure) were recorded by an infrared thermal imager and thermometers. Comparative analysis shows that the maximum surface temperature of the light-yellow brick is 7.3 °C lower than that of the ash black one, and the maximum surface temperature of hollow bricks is 5.6 °C lower than that of solid bricks. Thick bricks have a slightly low mean and maximum surface temperatures, and large bricks also have a low maximum surface temperature, but only deep coloured bricks. The analysis of variance revealed that for the maximum surface temperature, the three factors (i.e. colour, thickness and internal structure) have an interactive effect; for the mean surface temperature, only the colour and internal structure factors have a significant independent effect. This paper provides a feasible bottom-up cooling scheme for urban underlying surface.
Показать больше [+] Меньше [-]Natural radioactivity in building materials, indoor radon measurements, and assessment of the associated risk indicators in some localities of the Centre Region, Cameroon
2022
Ndjana Nkoulou II, Joseph Emmanuel | Manga, André | Saïdou, | German, Olga | Sainz-Fernandez, Carlos | Kwato Njock, Moïse Godfroy
The objective of the current study is to investigate the natural radioactivity of some building materials, the resulting long-term external and internal effective dose equivalents (EEDE and IEDE) analysis followed by indoor radon measurements, and the assessment of some radiological risk indicators associated with radon exposure. A total of 37 samples of building materials were analyzed with a sodium iodide detector (NaI (Tl)), and the computer code RESRAD-BUILD was used for the analysis of the EEDE and IEDE of the structural elements of the houses (walls and floor). For indoor radon measurements, 140 houses were selected, and in each of them was placed 01 RADTRAK dosimeter. Inhalation dose, total dose, and some radiological risk indicators were calculated. The specific activities of ²²⁶Ra, ²³²Th, and ⁴⁰K for the overall sampled building materials were found to vary between 10 ± 2–52 ± 7, 10 ± 1–95 ± 10, and 31 ± 1–673 ± 20 Bq kg⁻¹, respectively. The dwelling types with bare brick walls, cement mortar plastered walls, and concrete floors show EEDE and IEDE values well below the recommended limits. The corresponding dwelling type contributions to the measured average indoor radon concentration (42 ± 12 Bq m⁻³) are 22%, 13%, and 16%, respectively. Inhalation dose resulting from the measured indoor radon concentrations varies from 0.35 to 3.24 mSv y⁻¹ with a mean value of 0.96 ± 0.55 mSv y⁻¹, which represents about 65% of the total dose simulated (1.49 ± 0.88 mSv y⁻¹) by the RESRAD-BUILD code. The overall analysis of indoor radon-related radiological risk indicators shows low levels of risk relative to permissible limits.
Показать больше [+] Меньше [-]Evaluation of natural radioactivity levels and potential radiological hazards of common building materials utilized in Mediterranean region, Turkey
2022
Turhan, Şeref | Kurnaz, Asli | Karataşlı, Muhammet
Radiometric measurement of building materials is very important to assess the internal and external exposure caused by the ionizing radiation emitted from terrestrial radionuclides in building materials. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in fifty-eight samples of fifteen different structural and covering building materials commonly used in Osmaniye province located in the Mediterranean region of Turkey were measured by using gamma-ray spectroscopy. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K varied from 2.5 ± 0.1 (marble) to 145.7 ± 4.4 (clay brick), 1.3 ± 0.1 (marble) to 154.3 ± 4.1 (marble), and 8.6 ± 0.2 (sand) to 1044.1 ± 70.3 (granite), respectively. Radiological parameters (activity concentration index, alpha index, indoor absorbed gamma dose rate and the corresponding annual effective dose rate, and excess lifetime cancer risk) were estimated to evaluate the health hazards associated with these building materials. Since the estimated values of these parameters are within the recommended safety limits or criteria values, the use of the studied building materials in the construction of dwellings can be considered to be safe for the residents of the region.
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