Environmental Progress & Sustainable Energy最新文献

The issue of water depletion emerged as a life-threatening problem for the world due to urbanization, groundwater over-extraction, industrialization, and global warming. Current study aimed to address this issue by proposing a solution to distill wastewater using a multi-effect solar still. The study optimizes two condensation tray shapes, U and V, based on the yield produced and the temperatures achieved. Two solar still units with four stages of U and V-shaped trays were connected to a parabolic solar collector. To determine the optimal tray shapes, a rigorous optimization process was carried out using SolidWorks 2020. The optimization process yielded optimum heat flux values of 3.04e⁰¹ and 2.84e⁰¹ W/m² for U and V-shaped trays, respectively. Higher the value of heat flux suggested more energy available for condensation. Which was corroborated by physical findings that the U-shaped condensation tray was more efficient, producing an average per day yield of 2.519 L/m² h compared to the V-shaped tray's yield of 2.041 L/m² h. The findings provide strong evidence that the U-shape is a better tray shape for condensation purposes. Maximum yield for both units was observed during the peak temperature time between (13:00–15:00 h), indicating a direct correlation between yield and atmospheric temperature.

Microplastics (MPs) are plastic particles less than 5 mm and become a good carrier and vectors for contaminants in the environment. Current wastewater treatment technologies, including preliminary treatment, primary treatment, secondary treatment, and tertiary treatment, have a certain removal efficiency for MPs or nano-scale plastic particles. The settling treatment is employed in several wastewater treatment processes. This work built a settling model based on the Reynolds number, drag coefficient, and settling mechanism to predict the microplastics removal efficiency. Microplastics with larger density difference with wastewater, larger size, and CSF closer to 1 are easily captured and have a higher removal efficiency. The calculated removal efficiency according to density, size distribution, different shapes, and the surface loading rate in the operation of wastewater treatment is in a reasonable removal efficiency range. The removal efficiency increases when the surface loading rate decreases.

Thermoelectric generation (TEG) and organic Rankine cycle (ORC) technologies both have their respective limitations in recovering waste heat from ships. However, the combination of TEG and ORC is an effective approach to achieve cascaded waste heat recovery and improve heat utilization efficiency. There has been some progress in research on waste heat recovery in maritime applications based on TEG-ORC combined cycles. The selection of a working medium is a crucial element that directly influences the design and performance of the entire system, but there is limited research on the impact of different working fluids on combined cycle systems. In this study, a simulation model of a TEG-ORC combined cycle system was established to examine its output potential using two different working fluids R1234ze and a mixture of R245fa/R1234ze. The results demonstrate that compared to employing the R1234ze working medium, the combined cycle system with the mixed working medium achieved a 13% increase in maximum output power, a 102% improvement in optimum thermal efficiency, and a 53% reduction in optimum power production cost. Additionally, the power output distribution in the system utilizing the mixed working fluid was more uniform compared to the system employing a single working medium. This confirms the great potential of using a mixed working fluid in a combined cycle system.

The aim of this study was to utilize processed orange peel waste (TOP) as an adsorbent to remove Cu(II) and Ni(II) ions from aqueous solutions. As a result of systematic experiments to determine the optimal conditions, it was determined that the most suitable conditions for the effective removal of Cu(II) ions were 400 mg/L initial concentration, 100 min contact time, 0.2 g adsorbent dosage, and a solution pH of 5.92. Similarly, the optimal conditions for the removal of Ni(II) ions were determined by systematic experiments to be 300 mg/L initial concentration, 0.2 g adsorbent dosage, 100 min contact time, and a solution pH of 6.19. The systematic experiments also included further investigation of the surface properties of TOP, and promising results were obtained by tests at three different temperatures (298, 308, and 318 K). The adsorption capacities for Cu(II), Ni(II), and Ni(II) were determined as 72.99, 75.18, and 76.33 mg/g, 42.55, 44.44, and 46.29 mg/g, respectively. Further analysis of the adsorption kinetics revealed that the pseudo-second-order model accurately represented the experimental data for both ions. Thermodynamic investigations provided strong evidence that the adsorption process of these noble metal ions on TOP is endothermic and spontaneous. The results of this study emphasize that TOP, with its low cost, easy-to-use nature, and high adsorption capacity, can be considered a long-term solution for environmental remediation and water treatment in sustainable engineering applications.

Solar distillers are one of the oldest and simplest technologies for desalinating salt water using solar energy. The main problem is the low freshwater production compared to the amount of energy input from the sun. To overcome this problem, a solar distiller was developed using a parabolic trough concentrator to increase the freshwater yield. The geometry optimization of various parameters of the developed system was also studied using the particle swarm optimization (PSO) algorithm to obtain the optimal design and give the improved freshwater yield. The simulation is carried out based on the algorithm using the climatic condition data of Rabat City, Morocco. Numerical resolution of the energy balance equations was performed using MATLAB code. In terms of flexibility, speed, and global convergence, this method's final results were satisfactory. The maximum optimized freshwater yield using the PSO approach is 12.83 kg/m² and the maximum optimized energy and exergy efficiency were about 204.7% and 34.3%, respectively. Furthermore, the results showed that the absorber basin accounts for the highest exergy destruction, 88.7% of the total optimized exergy destruction was found from exergy analysis.

In general, two types of sitting and squatting toilets are used by people in the world, each of which has its own advantages and disadvantages from an environmental and health point of view. So far, no study has been done to compare these two types of toilets, precisely. Therefore, the precise comparison of these two types of toilets based on a simple literature review was the main purpose of this study. For this purpose, the amount of water consumption, toilet paper consumption, related diseases, ease of cleaning, odor problem, and the flexibility to equip with treatment and reuse systems in both types of toilets was compared. Squatting toilets is a better option in terms of water consumption, toilet paper consumption, ease of cleaning, and diseases related to body posture. In the case of infectious diseases, the sitting toilet has better conditions and in terms of flexibility to install the treatment and reuse systems, the conditions of both were almost similar. The odor problem in the sitting toilet is less than the squatting toilet. Since the advantages and disadvantages of both types of toilets are also complementary, the best option is to install both toilets together.

Data from radioactive Hanford tank waste samples was analyzed to assess whether trace metals present were incorporated into the bulk boehmite matrix or were simply intermingled with the bulk material and subsequent impacts to the boehmite dissolution rate. Results suggest that chromium is primarily blended into the bulk boehmite, with a small fraction present on the surface of the solids. However, increasing the level of chromium incorporation 30-fold decreased the dissolution rate of boehmite by only 8%, suggesting incorporation of chromium into these samples had a minimal impact on the dissolution rate. Iron was also found to be incorporated in the boehmite solids. Silicon appears to be simply intermingled and not blended into the boehmite crystals.

This article investigated the cradle-to-gate environmental impact of granulated blast furnace slag (GBFS) produced in the steel industry and replacement of blast furnace (BF) slag (50%) in place of clinker in Portland slag cement using GaBi software (Indian extension database). In case of GBFS production, maximum burden on the environment is due to BF slag production and the amount of electricity consumed (161 MJ/ton) during the granulation process. The influence of electricity sources on GBFS production was studied via scenario analysis. For investigation, solar and thermal electricity mixes were considered in 50:50 and 75:25 ratios. For the 75:25 ratios, the abiotic depletion potential (fossil), acidification, eutrophication, global warming, and human toxicity potential show a decreasing trend of approximately 45%, 49%, 48%, 46%, and 41%, respectively. The scenario analysis of BF slag transportation (from 100 to 750 km) demonstrates a negative impact due to fuel. The results quantitatively confirm that the addition of GBFS can lower the overall impact for construction and steel industries.

As waste heat dryers (WHD) exhibit conservation of energy with environmental and economic benefits, the direct use of waste hot air rejected from the outdoor unit of a window air conditioning (AC) unit for drying banana slices is demonstrated experimentally in the present research work. For this purpose, a drying chamber was directly coupled to an AC unit (AC-WHD) and analyzed its performance during banana slice drying by revisiting the concepts of generalized drying curve and drying performance index (DPI). The experimental data set of moisture content ratio obtained with AC-WHD matched well with the generalized drying curve and the DPI value was found to be 0.999. It was found that the waste air supplied by the AC unit to the drying chamber was hot (≈ 50°C) and 28% dry, which aided the drying process. The thermodynamic performance of AC-WHD was also evaluated using warm and wet exergy to provide insight into the mechanism of AC-WHD drying. The exergy based sustainability index was higher while the exergetic destruction coefficient and environmental impact factor were lower for AC-WHD when compared to literature values of the solar drying method. The findings of this research work indicate the practicality of coupling AC units with dryer units to address sustainable development goals (SDG).