| 1. |
- Ahmed, Tahmeed, et al.
(författare)
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Evaluation of the impacts of seawater integration to electrocoagulation for the removal of pollutants from textile wastewater
- 2024
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Ingår i: Environmental Sciences Europe. - : Springer Nature. - 2190-4707 .- 2190-4715. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Recent textile industry expansion has a major environmental impact if not addressed. Being a water intensive industry, textile manufacturing is usually associated with wastewater management challenges. Electrocoagulation (EC) is recognized as one of the effective solutions to address these challenges. This study aims to investigate the potential of integrating seawater into the EC process for textile wastewater treatment, targeting optimal pollutant removal efficiencies. A simple electrolytic reactor was designed to investigate the removal efficiency of these treatments for chemical oxygen demand (COD), total suspended solids (TSS), turbidity, and color from textile wastewater at different seawater percentages and retention times. Notably, the addition of seawater not only improves the EC process efficiency but also significantly dilutes pollutants, reducing their concentrations. This dual effect enhances removal efficiency and dilution optimizes the treatment outcome. The highest removal efficiencies were achieved for COD (47.26%), TSS (99.52%), turbidity (99.30%), and color (98.19%). However, pH, dissolved oxygen (DO), and electrical conductivity increased with increasing retention times and seawater percentages in the EC process. Moreover, Seawater − EC integration reduces power usage to 15.769 Am−2 and costs approximately 0.20 USD/m3. To assess the effects of the retention times and seawater percentages on pollutant removal from textile wastewater, an analysis of variance (ANOVA) was conducted utilizing the Design-Expert 11 software. The best model obtained using Central Composite Design (CCD) was quadratic for COD (R2 = 0.9121), color (R2 = 0.9535), turbidity (R2 = 0.9525), and TSS (R2 = 0.9433). This study suggests that higher seawater percentages and longer retention times effectively eliminate contaminants but increase ion concentrations.
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| 2. |
- Ahsan, Amimul, et al.
(författare)
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Modeling the impacts of best management practices (BMPs) on pollution reduction in the Yarra River catchment, Australia
- 2023
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Ingår i: Applied water science. - : Springer. - 2190-5487 .- 2190-5495. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Pollution of a watershed by different land uses and agricultural practices is becoming a major challenging factor that results in deterioration of water quality affecting human health and ecosystems. Sustainable use of available water resources warrants reduction of Non-Point Source (NPS) pollutants from receiving water bodies through best management practices (BMPs). A hydrologic model such as the Soil and Water Assessment Tool (SWAT) can be used for analyzing the impacts of various BMPs and implementing of different management plans for water quality improvement, which will help decision makers to determine the best combination of BMPs to maximize benefits. The objective of this study is to assess the potential reductions of sediments and nutrient loads by utilizing different BMPs on the Yarra River watershed using the SWAT model. The watershed is subdivided into 51 sub-watersheds where seven different BMPs were implemented. A SWAT model was developed and calibrated against a baseline period of 1998–2008. For calibration and validation of the model simulations for both the monthly and annual nutrients and sediments were assessed by using the Nash–Sutcliffe efficiency (NSE) statistical index. The values of the NSE were found more than 0.50 which indicates satisfactory model predictions. By utilizing different BMPs, the highest pollution reduction with minimal costs can be done by 32% targeted mixed-crop area. Furthermore, the combined effect of five BMPs imparts most sediments and nutrient reductions in the watershed. Overall, the selection of a BMP or combinations of BMPs should be set based on the goals set in a BMP application project.
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| 3. |
- Das, Sushil K., et al.
(författare)
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Calibration, validation and uncertainty analysis of a SWAT water quality model
- 2024
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Ingår i: Applied water science. - : Springer Nature. - 2190-5487 .- 2190-5495. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Sediment and nutrient pollution in water bodies is threatening human health and the ecosystem, due to rapid land use changes and improper agricultural practices. The impact of the nonpoint source pollution needs to be evaluated for the sustainable use of water resources. An ideal tool like the soil and water assessment tool (SWAT) can assess the impact of pollutant loads on the drainage area, which could be beneficial for developing a water quality management model. This study aims to evaluate the SWAT model’s multi-objective and multivariable calibration, validation, and uncertainty analysis at three different sites of the Yarra River drainage area in Victoria, Australia. The drainage area is split into 51 subdrainage areas in the SWAT model. The model is calibrated and validated for streamflow from 1990 to 2008 and sediment and nutrients from 1998 to 2008. The results show that most of the monthly and annual calibration and validation for streamflow, nutrients, and sediment at the three selected sites are found with Nash–Sutcliffe efficiency values greater than 0.50. Furthermore, the uncertainty analysis of the model shows satisfactory results where the p-factor value is reliable by considering 95% prediction uncertainty and the d-factor value is close to zero. The model's results indicate that the model performs well in the river's watershed, which helps construct a water quality management model. Finally, the model application in the cost-effective management of water quality might reduce pollution in water bodies due to land use and agricultural activities, which would be beneficial to water management managers.
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| 4. |
- El Jery, Atef, et al.
(författare)
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Industrial oily wastewater treatment by microfiltration using silver nanoparticle-incorporated poly (acrylonitrile-styrene) membrane
- 2023
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Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 35:1
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Tidskriftsartikel (refereegranskat)abstract
- Membrane filtration exhibit operational limitations such as biofouling, which leads to concentration polarization and reduces permeability and selectivity, despite advantages such as low operating cost, high selectivity, and permeability. In recent years, the antibacterial properties of silver nanoparticles (AgNPs) have been investigated for improving membrane processes; however, the fouling phenomena in presence of AgNPs in the membrane matrix have not been fully discussed. Herein, the antifouling properties of a poly (acrylonitrile-styrene) copolymer incorporated with AgNPs were studied in a microfiltration membrane process. The Creighton method was used to synthesize AgNPs, and the effects of AgNPs on the porosity, morphology, pore size, mechanical strength, permeability, and selectivity of the membranes were investigated. Moreover, to investigate the biofouling of the obtained membranes, microfiltration of industrial oily wastewater was performed at constant pressure over three cycles. Using AgNPs in the membrane matrix resulted in enhanced antifouling properties of the copolymer membrane, which is related to the structure of the AgNPs in the casting solution, as proven by SAXS analysis. The results show that the CFU% for Staphylococcus aureus and E.coli reach 2% and 6%, respectively. Finally, the Derjaguin–Landau–Verwey–Overbeek (DLVO) thermodynamic model was applied to study the antifouling mechanism, correctly predict the separation behavior in the membrane, and design, simulate, and optimize the separation processes in the membrane separation plantsa. The DLVO model could predict the separation behavior in the synthesized membranes, and the poly(acrylonitrile-styrene) copolymer membranes containing AgNPs were proven have promising industrial wastewater treatment applications.
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| 5. |
- Khan, Md. Habibur Rahman Bejoy, et al.
(författare)
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Evaluation of the surface water quality using global water quality index (WQI) models: perspective of river water pollution
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Rapid industrialization, urbanization, global warming, and climate change are compromising surface water quality across the globe. Consequently, water conservation is essential for both environmental sustainability and human survival. This study assesses the water quality of the Jamuna River in Bangladesh at five distinct sites during wet and dry seasons. It employs six global water quality indices (WQIs) and contrasts the results with Bangladesh's Environmental Quality Standard (EQS) and the Department of Environment (DoE) criteria. The WQI models used are the Weighted Arithmetic WQI (WAWQI), British Columbia WQI (BCWQI), Canadian Council of Ministers of the Environment WQI (CWQI), Assigned WQI (AWQI), Malaysian WQI (MWQI), and Oregon WQI (OWQI). Fifteen physicochemical parameters were analyzed according to each WQI model's guidelines. The findings reveal that most parameters surpass the standard permissible values. The WQI model results indicate that the average water quality across the five sites falls into the lowest category. A comparison of the WQI models suggests potential correlations between WAWQI and AWQI, as well as between MWQI and OWQI. The straightforward presentation of the WQI models indicates that while the river water requires treatment for household and drinking use, it remains suitable for irrigation. The decline in water quality is likely attributable to human activities, urbanization, municipal waste disposal, and industrial effluents. Authorities must prioritize regular monitoring and assessment of water quality to address the identified challenges. Restoring the water to an acceptable standard will become increasingly difficult without proactive measures.
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| 6. |
- El Jery, Atef, et al.
(författare)
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Isotherms, kinetics and thermodynamic mechanism of methylene blue dye adsorption on synthesized activated carbon
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The treatment of methylene blue (MB) dye wastewater through the adsorption process has been a subject of extensive research. However, a comprehensive understanding of the thermodynamic aspects of dye solution adsorption is lacking. Previous studies have primarily focused on enhancing the adsorption capacity of methylene blue dye. This study aimed to develop an environmentally friendly and cost-effective method for treating methylene blue dye wastewater and to gain insights into the thermodynamics and kinetics of the adsorption process for optimization. An adsorbent with selective methylene blue dye adsorption capabilities was synthesized using rice straw as the precursor. Experimental studies were conducted to investigate the adsorption isotherms and models under various process conditions, aiming to bridge gaps in previous research and enhance the understanding of adsorption mechanisms. Several adsorption isotherm models, including Langmuir, Temkin, Freundlich, and Langmuir–Freundlich, were applied to theoretically describe the adsorption mechanism. Equilibrium thermodynamic results demonstrated that the calculated equilibrium adsorption capacity (qe) aligned well with the experimentally obtained data. These findings of the study provide valuable insights into the thermodynamics and kinetics of methylene blue dye adsorption, with potential applications beyond this specific dye type. The utilization of rice straw as an adsorbent material presents a novel and cost-effective approach for MB dye removal from wastewater.
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| 7. |
- Kahn, Md. Shafiquzzaman
(författare)
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Sound quality evaluation of heavy-duty engines in free field conditions
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Annoyance response to vehicle noise is commonly reported. The impact reduction measures must therefore be measured scientifically. A scientific system for describing and defining annoyance is therefore required. There is furthermore a need to reduce the annoying components of the sound of vehicles. The engine of a vehicle is one of the predominant sources of vehicle noise which cause annoyance. The sounds of engines heard outside of engines at idling, running and accelerating conditions have been reported to cause annoyance throughout the world. This study of sound quality focuses on noise heard outside vehicles, termed external vehicle noise, and which is outside the interior of the car, in free field conditions. The objectives of the study are a) the development of new descriptors and annoyance prediction models at idling and running conditions, b) comparison of several rating methods, c) testing of several recording and reproduction techniques, d) testing of the long-term repeatability of annoyance judgement obtained in tests, and e) comparison of the combustion process of various fuels in terms of annoyance. An annoyance prediction model for idling engine sound was developed using multivariate analysis on the basis of a new parameter which is termed "Ear Reasoning Range". Two further psychoacoustic descriptors, loudness and impulsiveness were also defined in the model. The sound spectrum which caused least annoyance was obtained by subjective adjustments to an idling engine sound. The quality of the sound was validated by subjective judgements, by test persons, and by objective measurements. An annoyance index for heavy-duty engine noise was developed on the basis of three psychoacoustic descriptors: loudness, sharpness, and harmonic ratio. The model was validated internally and externally and gave good predictions of annoyance judgement of 6-cylinder inline engine noise. Three rating techniques known as the method of paired comparisons, the method of equal-appearing intervals and the method of successive intervals were investigated with respect to annoyance judgements of engine noise in free field conditions. The method of successive intervals was shown to be useful for annoyance judgements of engine noise for a large number of samples. The annoyance response to engine sounds recorded by an artificial head did not differ significantly from that recorded by an orthostereophonic technique. The variance in annoyance response for headphone reproduction was higher than that for loundspeaker reproduction. It was found that both recording techniques gave similar predictions of annoyance. Subjects preferred loudspeaker reproduction to headphone reproduction. There was no significant difference in annoyance judgements between experienced and naive listeners. Annoyance judgements of engine noise were shown to be consistent when subjects were asked to judge the same stimuli on two occasions 10-20 days apart. A comparison of multivariate analysis and neural networks for modeling annoyance of engine noise in free field conditions was investigated. Partial Least Squares (PLS) regression and Neural Networks were used to develop the annoyance prediction models on the basis of loudness, sharpness and harmonic ratio (rumble noise). PLS regression and Neural Networks gave similar prediction of annoyance for engine noise but neural networks gave greater prediction accuracy than did PLS regression. Annoyance judgements of engine sounds in respect to six different fuels were investigated by forty subjects. The annoyance judgements were found to be consistent with the annoyance index based on loudness, sharpness and harmonic ratio. Engine sounds due to ethanol fuel with 9% beraid were rated as least annoying whereas engine sounds due to a mixture of diesel and ethanol fuels were rated as most annoying.
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| 8. |
- Khan, Md. Shafiquzzaman
(författare)
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Essays on ergonomics
- 1993
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 9. |
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