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Effects of Corn Straw Biochar, Soil Bulk Density and Soil Water Content on Thermal Properties of a Light Sierozem Soil
2023
Y. Q. Li, L. J. Li, B. W. Zhao, Y. Zhao, X. Zhang and X. Dong
This research aimed to quantify the effects of biochar derived from corn straw on soil thermal conductivity, capacity, and diffusivity. Firstly, the amount of biochar application (w/w) added to light sierozem soil was 0% to 5%, and the mixtures were packed into soil columns at a consistent bulk density (1.20 g.cm-3). Secondly, soil columns with a consistent biochar addition rate (5%) were packed to different bulk densities of 1.30, 1.25, 1.20, 1.15, and 1.10 g.cm-3. Soil thermal characteristics were measured under the control of soil moisture content from 0% to 40%. Under consistent bulk-density conditions, biochar could significantly reduce soil thermal conductivity and diffusivity. Still, there wasn’t a significant influence on soil heat capacity in most soil moisture content levels. With the decrease of soil bulk density, soil thermal conductivity, capacity, and diffusion coefficient reduced significantly. As soil water content increased, all the indexes of thermal properties largely improved, and the effects were much more significant than those of biochar amendment and bulk density change on soil thermal performances. This research could supply an implication to evaluate the influence of biochar amendment on soil thermal performances.
Показать больше [+] Меньше [-]Efficacy of Nanofertilizers Over Chemical Fertilizers in Boosting Agronomic Production
2023
A. Khatri and R. Bhateria
Global agricultural production cannot catch the increasing population’s exigency. At different times, the world has faced food crises of varying intensity. Many steps have been taken after that to encounter the rising concerns. Nowadays, nanofertilizers are being experimented with as an alternative to conventional fertilizers. Nanofertilizers can be classified as macronutrients and micronutrients nanofertilizers. Synthesis of macronutrient nanofertilizers (nitrogen, phosphorus, potassium, calcium, magnesium, etc.) and micronutrient nanofertilizers (iron, boron, zinc, copper, silicon, etc.) can be done using chemical and green synthesis methods, which involves reducing agents, capping agents, dendrimers, microbial synthesis, solvents, and others. Composition of the nanofertilizers can be done using top-down and bottom-up approaches incorporating hydrocarbon polymer, dendrimers, microbes, etc., which decides their usage in various crops depending upon the requirement of the plant. Engineered nanofertilizers can improve crop yield by mitigating environmental pollution, environmental stress, and plant diseases. However, the unsystematic use of nanofertilizers can be a hurdle in its utilization. This article discusses various types of nanofertilizers with their unique properties and applications. Each category of nanofertilizers is explained considering their composition, particle size, concentrations applied, benefited plant species, and plant-growth enhancement aspects.
Показать больше [+] Меньше [-]Biodegradation and Kinetic Study of Hazardous Metribuzin Herbicide Using a Novel Soil Bacterial Isolate Olivibacter oleidegradans Strain SP01 in Aqueous Solution
2023
Sulbha R. Kadam and Madhuri K. Pejaver
In the present work, degradation of the herbicide metribuzin (C8H14N4OS) has been performed. A novel metribuzin-degrading bacterium, Olivibacter oleidegradans strain SP01, was isolated from the metribuzin-contaminated soil by an enrichment technique. To investigate the effect of various parameters on metribuzin degradation, various experiments were performed at an initial concentration in the range of 20-100 mg.L-1, a pH of 5-9, and a temperature of 25-40°C. Around 85% of the highest percentage degradation of metribuzin was obtained at a concentration of 20 mg.L-1 in 120 h under optimized conditions. The current work for the Metribuzin degradation study fits well with first-order reactions. Also, at higher concentrations, i.e., 100 mg.L-1, only 40.3% degradation of metribuzin was observed. The Olivibacter oleidegradans strain SP01 has the potential to be extremely beneficial in the removal of Metribuzin from the environment.
Показать больше [+] Меньше [-]Efficient Copper Adsorption from Aqueous Solution by Dictyuchus sterile Pellets
2023
Rana Hadi Hameed Al-Shammari, Shaimaa Satae M. Ali and Moayad Salih Hussin
A common heavy metal pollutant of water resources, copper (II), can cause serious health problems or even death. Over the past few years, several filamentous fungi strains have been isolated, identified, and tested for their ability to bio-adsorb heavy metals for potential use in the bio-remediation of copper from wastewater. In this study, variables, including the dosage of fungal pellets, temperature, pH, time, initial copper concentration, and agitation rate, were assessed to select the best conditions for the adsorption of copper by Dictyuchus sterile pellets. To identify the active groups responsible for metal adsorption, microscopic observations were made using a light microscope and scanning electron microscope. The copper adsorbent was then analyzed before and after adsorption using an atomic adsorption spectrophotometer and Fourier transform infrared spectroscopy. The ideal adsorption conditions were: fungal pellets with a wet weight of 1 g.L-1 at a temperature of 25°C, pH 5.5, the initial copper concentration of 100 ppm, and shaking at a speed of about 250 rpm for 72 h to achieve a removal efficiency rate of 95%. Copper adsorbed with the biomass of the fungal pellets was 57 mg.g-1. The use of fungal pellets would be a method that can be used to increase the surface area of adsorption and also is thought to be one of the most cost-effective ways to remove trace metals from polluted water.
Показать больше [+] Меньше [-]Strategic Monitoring of Groundwater Quality Around Olusosun Landfill in Lagos State for Pollution Reduction and Environmental Sustainability
2023
O.J. Oyebode, F.O. Jimoh, S.M. Ajibade, S.A. Afolaluand F.A. Oyebode
As urbanization and population increase in the megacity, there is a need for engineering intervention and strategic monitoring of groundwater around landfills for environmental sustainability, pollution reduction and public health. This study evaluated water’s physical and chemical parameters in wells and boreholes near the Olusosun landfill in Lagos State to determine how they impact groundwater quality. An Atomic Absorption Spectrometer (AAS) was used to evaluate groundwater samples obtained from five locations within the dump site. Some water parameters, such as dissolved oxygen (DO), iron (Fe), lead (Pb), manganese (Mn), and magnesium (Mg), had concentrations that were higher than the WHO, NESREA, and Nigerian Standard for Drinking Water Quality (NSDWQ) standard limits in some sampling sites, with mean concentrations of 0.33 mg.L-1, 0.04 mg.L-1, 0.74 mg.L-1, and 0.74 mg.L-1, respectively. A small amount of lead was identified in the groundwater of the study area. A major source of air and groundwater pollution, the Olusosun landfill has a detrimental impact on the health of those who live there. Solid waste, groundwater interactions, and contaminated migration into the nearby neighbourhood were studied. It was observed that the degradation of waste products in dump sites releases harmful leachate into the groundwater. Even though some heavy metal concentrations in the study area are still within WHO, NESREA, and NSDWQ standard limits, investigations and further monitoring should be conducted regularly to assess the concentrations of heavy metals in groundwater.
Показать больше [+] Меньше [-]Boron Isotopic Systematics and Its Significance in Natural Processes: An Overview
2023
Tanya Srivastava and Nishchal Wanjari
In recent years, interest in boron has expanded from microscopic to macroscopic levels, and several studies have contributed to understanding the role of boron in earth and natural processes. The boron isotopic composition provides a unique perspective into the crystallization process in granites, pegmatites, and temperature variations. Boron isotopic studies have been used as a tracer to understand geothermal systems, rivers, rock processes, reconstruction of pH and pCO2, groundwater pollution, and further help in understanding the changes which have occurred in oceans through geological time. Furthermore, boron isotopes have also been utilized to understand the genesis of ores and understanding subduction processes and as a tracer in groundwater pollution. In plants, it acts as a micronutrient. However, its deficiency and the excessive amount may inhibit the growth of plants, bacteria, and fungi and may also affect the soil and aquatic microflora. Boron maintains and regulates several metabolic pathways, and its quantity above a certain level may prove detrimental to the environment. This overview explains boron isotope variations and their implications in earth sciences and natural processes.
Показать больше [+] Меньше [-]Removal of H2S from Biogas Using Thiobacillus sp.: Batch and Continuous Studies
2023
R. Shet and S. Mutnuri
Anaerobic digestion produces biogas which usually contains 60-70% of methane (CH4), 30-40% of carbon-di-oxide (CO2), and 10-2,000 ppm hydrogen sulfide (H2S). The concentration of H2S depends upon the type of substrate. H2S tends to corrode pipes and machines carrying them. The high concentrations of H2S present in biogas may adversely affect electricity generation. Hence, the removal of H2S and enrichment of biogas with CH4 is an essential step towards higher energy production. In the present study, the biological method of removing H2S using Thiobacillus sp. was demonstrated for a one cu.m anaerobic co-digestion (ACD) unit running on an organic fraction of municipal solid waste (OFMSW) and septage sludge. Initial lab scale studies were conducted by collecting the biogas generated from 1 cu.m digesters, and continuous experiments were optimized for the process parameters such as flow rate, the volume of medium with culture, time, the height of the column, column composition, etc. The raw biogas was purged in a liquid medium (LM) with a culture containing Thiobacillus sp. The studies with the LM containing Thiobacillus sp. culture showed a 68% removal of H2S in the first 8 min, and the saturation occurred at 75 min when the time-dependent experiment was studied. The smaller flow rate (0.48 L.min-1) and highest volume of culture (500 mL) showed better results than other parameters. The highest and average oxidation rates of sulfate were recorded as 39 and 40.3 ppm.sec-1, respectively, for 0.48 L.min-1 flow rate and 500 mL of the culture volume. In the column studies, a column containing cocopeat (CP) was studied for its efficiency in removing H2S. At a flow rate of 0.9 L.min-1, 25% adsorption was encountered and reached saturation at 90 min. The bed height of 9 inches with CP and plastic support (PS) showed a 20% H2S removal. The filling ratio of CP and PS (1:1) was the best ratio for proper gas passage with optimal time for adsorption/absorption. The kinetic, isotherm, and continuous models helped to understand the capacity of the adsorbent. Freundlich, Yoon-Nelson, and BDST model were best fit for the present study. A pilot scale setup for one cu.m biogas reactor showed an average of 50% removal of H2S for LM with culture, and an additional 20% removal was possible by the introduction of a column along with the liquid bed in series. An overall efficiency of 70-75% of H2S removal was achieved. No significant CH4 loss was encountered during the study.
Показать больше [+] Меньше [-]Radiation Risk Among Children due to Natural Radioactivity in Breakfast Cereals
2023
H. H. Abbas, Shaymaa A. Kadhim, Shatha F. Alhous, H. H. Hussein, F. A. AL-Temimei and H. A. A. Mraity
Breakfast cereal is one of the common foods for children’s nutrition. It is made from sugar, barley, calcium carbonate, salt, maize, peanuts, molasses, and honey. Therefore, assessing the levels of radioactivity in breakfast cereal is essential for children’s health. Gamma-ray spectrometry NaI(Tl) was used to measure the radiation hazard in ten samples collected from the Iraqi market. The corresponding radiation dose quantities and hazard indices were also calculated. The average concentrations of 226Ra, 232Th, and 40K were found to be 18.195, 20.965, and 796.500 (Bq.kg-1). The annual effective dose equivalent (AEDEin), annual ingestion dose (AID), and the risk of cancer incidence (ELCR) were all seen to be within the accepted levels, except the annual gonadal equivalent dose (AGED). Radiation hazard index values (i.e., Iγ, Iα, and Hin) were noticed to be lower than unity, except Iγ was much higher than the internationally permissible limits for the samples of BGF5, BGF6, and BGF7 recommended by UNSCER2000. Therefore, the study findings reveal that this type of cereal can be considered a safe feeding material for children’s health.
Показать больше [+] Меньше [-]Statistical Model for Tube Settler Clarifier at Different Operational Conditions
2023
Abdulmuhsin S. Shihab and Aladdin M. Ahmad
The present study aimed to find a relationship between turbidity removal percent in tube settler clarifier and independent variables (tube inclination, alum dosage, and surface loading rate) by constructing a statistical model and categorizing these explanatory variables according to their impact on turbidity removal percentage. A pilot scale of tube settlers was designed and fabricated to conduct the experiments. It consisted of a coagulation and flocculation basin, pre-tube settler chamber, and tube settler. Alum was used to coagulate the Tigris river raw water at different dosages. After flocculation, water is transferred to the pre-tube settler chamber and flows through the tube settler. It consists of four tubes of square section, 4 centimeters in diameter, with the flexibility of changing tube length and inclination angle to obtain different levels of surface loading rate. More than 120 experiments were conducted, and the results were analyzed statistically. A regression model was found with a coefficient of determination of 0.802 between turbidity removal percentage as a dependent variable and each tube inclination, alum dosage, and surface loading rate as independent variables. The model is considered good as the model’s relationship between actual and predicted values has a slope of one and a constant near zero. Surface loading rate has the highest effect on turbidity removal percentage with 4.44 times that of inclination angle and 2.5 times for the optimum alum dosage model. The study concluded that the linear model is suitable to represent the performance of tube settlers at optimum alum dosage.
Показать больше [+] Меньше [-]Modeling of Activated Sludge Process Using Multi-Layer Perceptron Neural Networks
2023
Saurabh Sahadev , G. Madhu and M. Roy Thomas
Mathematical Modeling of the activated sludge process (ASP) enhances the understanding of the process and improves the quality of the effluent released. However, as the process is complex and nonlinear, mathematical modeling of the process has been a challenge. In this study, multi-layer perceptron neural networks (MLP-ANN) are investigated to predict water quality parameters for better control of wastewater treatment plants employing an activated sludge process. The study area selected was in a central district of the southern state of India. The parameters to be investigated are biochemical oxygen demand (BOD), suspended solids (SS), and pH. The model is evaluated based on statistical parameters of correlation coefficient R and mean square error (MSE). The neural network toolbox of MATLAB 2015b is used for modeling and simulation study. It has been found that effluent biochemical oxygen demand was predicted with a maximum correlation coefficient of 0.927 and minimum mean square error of 0.0022, effluent suspended solids were predicted with a maximum correlation coefficient value of 0.947 and minimum mean square value of 0.0058, effluent pH was predicted with a maximum correlation coefficient value of 0.8299 and minimum mean square value of 0.0132.
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