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Efficient Copper Adsorption from Aqueous Solution by Dictyuchus sterile Pellets Full text
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.
Show more [+] Less [-]Strategic Monitoring of Groundwater Quality Around Olusosun Landfill in Lagos State for Pollution Reduction and Environmental Sustainability Full text
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.
Show more [+] Less [-]Boron Isotopic Systematics and Its Significance in Natural Processes: An Overview Full text
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.
Show more [+] Less [-]Removal of H2S from Biogas Using Thiobacillus sp.: Batch and Continuous Studies Full text
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.
Show more [+] Less [-]Radiation Risk Among Children due to Natural Radioactivity in Breakfast Cereals Full text
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.
Show more [+] Less [-]Statistical Model for Tube Settler Clarifier at Different Operational Conditions Full text
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.
Show more [+] Less [-]Modeling of Activated Sludge Process Using Multi-Layer Perceptron Neural Networks Full text
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.
Show more [+] Less [-]Susceptibility Evaluation of Debris Flow Disaster in Plateau Hydropower Cascade Development Reservoir Area Full text
2023
Feng Yang, Xudong Hu, Zhenyao Xia, Lei Cui and Qi Yang
The Rumei Hydropower Station is a typical cascade hydropower development project in a plateau area. The dam site is located in an area with complex topography, lithology, and geological structure. Geological disasters are developed in the area, mainly debris flow. Thus, taking the dam site and the surrounding areas as key evaluation objects, the engineering geological characteristics, geological environment characteristics, and the susceptibility and risk of geological disasters that may be caused are predicted and evaluated. The main methods used in this assessment are the binary logistic regression model and expert evaluation. The results show that the susceptibility to geological disasters is small and medium. The results of this study could provide a scientific basis for the rationality of the general layout and site selection of the project construction in the plateau water elevator level development reservoir area.
Show more [+] Less [-]A Novel Green Approach for Lead Adsorption and Isotherm Evaluation Full text
2023
M. Dharsana and J. Prakash Arul Jose
Environmental damage due to the discharge of organic pollutants and heavy metal toxins has become a major topic of concern for the past couple of years. Using just a natural adsorbent to solve wastewater concerns has lately gained popularity as an ecologically acceptable solution that encourages long-term growth. A range of approaches, including adsorption to the surface of agricultural leftovers, have been used to minimize heavy metals in an aqueous medium. Lead is amongst the most hazardous and widely discovered toxic substances in industrial waste. Citrus limetta peel powder, Banana peel powder, and Betel leaf powder were chosen as adsorbents in this study to absorb synthetic lead from an aqueous solution since they are low-cost materials. Our research aims to find natural bio-sorbents that can remove highly hazardous Pb2+ ions from aqueous solutions. The importance of contact time, concentrations, adsorbent-based dose, and pH in the adsorption process is investigated. The adsorption rate for betel leaves, Citrus limetta peel, and banana peel was 5, 10, 15, 20, and 25 g.L-1. Citrus limetta peel (10 g.L-1), banana peel (5 g.L-1), and betel leaf (5 g.L-1) provide the highest lead adsorption. Material characterization is used to determine the lead nitrate process in lead adsorption. The capacity of the lead-adsorbing substances to achieve adsorption equilibrium was assessed and estimated using linear Freundlich and Langmuir isotherms, with the experimental data fitting the Freundlich isotherm models.
Show more [+] Less [-]Effect of Geographic Altitude on Carbon Stock in two Physiographic Units of the Reserved Forest of the Universidad Nacional Agraria de la Selva Full text
2023
M. Reategui, D. Reategui, E. Morales, R. Reategui and C. Aguirre
The objective of the research was to evaluate the effect of geographic altitude on the carbon stock in two physiographic units of the Reserved Forest of the Universidad Nacional Agraria de la Selva, Tingo Maria-Huanuco. The methodology used was the field manual for the remeasurement and establishment of plots of the Amazon Forest Inventory Network (RAINFOR), for which 2 hectares were permanently established (one hectare in low and high hills) in which the diameter (greater than or equal to 10 cm) and the height of the trees were measured. Finally, the density of the wood was obtained from previous studies. The pantropical model formula was used to estimate the carbon stock. The results show that geographic altitude significantly affects carbon stock (p < 0.05) in low and high-hill forests, concluding that this may be due to differences in meteorological variables such as precipitation, temperature, and humidity.
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