Environmental Progress & Sustainable Energy最新文献

This article presents an effective, economical, and health-safe experimental work to improve the solar distiller's performance using cement conical fins. To demonstrate the effectiveness of conical cement fins, two distillers were designed and built, in the first distiller; a basin was made from cement (SSSD-CB). In the second distiller, the uniformly distributed cement conical fins are installed in the basin (SSSD-CB&CCF). The results presented that the cumulative water produced from SSSD-CB and SSSD-CB&CCF reached 3460 and 4750 mL/m² day, respectively. These results indicated that the conical cement fins represent a good design that improves the yield by 37.28%. Also, the average improvement in the exergy and energy efficiencies for SSSD-CB&CCF reached 71.24% and 37.3%. The economic analysis showed that using conical cement fins reduced distilled costs by 25.38%.

To study the impact of different water-nitrogen regulation modes on the carbon cycle of greenhouse tomatoes and determine optimal irrigation and nitrogen application levels to enhance carbon absorption and minimize greenhouse gas emissions. This study employed three irrigation levels (100%, 80%, and 60% of ET0) and three nitrogen application levels (240, 192, and 144 kg·ha⁻¹), along with a control group (W1N1, i.e., 100% ET0-240 kg·ha⁻¹). Gas-chromatography methods were used to monitor CH₄ and soil CO₂ emissions, while assessing dry matter, carbon content, and carbon fixation capacity of tomato organs throughout the growth period. Additionally, a system for evaluating the net ecosystem carbon budget of facility tomatoes was developed based on net primary productivity. Results indicated reduced CH₄ and soil CO₂ emissions with decreased irrigation and nitrogen application. Dry matter, carbon content, and carbon fixation of tomato organs initially increased with reduced nitrogen and irrigation but then declined. The W2N2 (80% ET0-192 kg·ha⁻¹) treatment showed maximal values for dry matter, carbon content, carbon fixation, net primary productivity (NPP), and gross primary productivity (GPP). Findings suggest a positive net ecosystem carbon budget under reduced water and nitrogen conditions, indicating carbon absorption. Specifically, the W2N2 treatment outperformed others in net carbon absorption, highlighting its potential as an effective mode for enhancing carbon sequestration in the region.

The escalating global volume of sewage discharge presents a formidable challenge for sewage treatment facilities, necessitating the efficient utilization of sewage. Given the substantial demand on water resource during anaerobic digestion (AD), this study investigated the feasibility of substituting pure water with sewage as the main water source for AD using six diverse lignocellulosic wastes (rice straw, vinegar residue, cattle manure, sheep manure, napkin, and office wastepaper) as feedstocks. The results showed that the methane production of lignocellulosic waste + raw wastewater (WW) during AD increased by at least 5% compared with the control groups. Specially, the cumulative methane yield of napkin mixed with the WW reached to 218.3 mL/gVS with the increase of 47.8% compared with the control group (147.7 mL/gVS). The results indicated that the relative abundance of characteristic bacteria and methanogenic archaea during AD was closely related to the kinds of feedstocks and water source. The addition of WW increased the relative abundance of bacteria and archaea in the digester, which might be the main reason for the higher methane production with the addition of WW. Treated wastewater and reclaimed water had a relatively neglectable impact on the microbial community structure in AD. This study not only saved water resources in AD but also provided a strong reference for resource utilization of sewage and organic solid waste.

Turbidity affects the aesthetic and overall quality of water and therefore, its prediction and modeling are essential for designing treatment strategies. In the present research, the outcomes of altering parameters and optimizing the removal of turbidity using response surface methodology (RSM), artificial neural network (ANN), support vector machine (SVM), and K-nearest neighbor (KNN) based on a statistically designed set of experiments are examined. pH, coagulant dose, and settling time are considered process variables. The optimum removal of turbidity was obtained at a pH range of 6–8, coagulant dosage of 20–35 mg/L, and settling time of 30–45 min for the coagulants. The best turbidity reduction (60%) was achieved using alum coagulant (30 mg/L), at a pH of 7.5 and settling time for 45 min. All the models proved to be effective in demonstrating how the operating variables being studied influence the removal of turbidity from the aqueous solution. In contrast to the RSM, SVM, and KNN models, the ANN more accurately characterized the parametric impact.

Performance improvement of cookstoves has a vital role in reducing indoor air pollution and deforestation. In this study, biomass-based cook stoves onsite data survey and experimental approaches were carried out to evaluate the performance of different cook stoves. Based on this feasibility research, it was shown that firewood accounted for 75% of the fuel type usage. The results of several studies and experimental performance testing indicated that the efficiency of cook stoves for 3-stone, lakech, mirt, gonze, tikikil, and pyrolysis stoves was 10%, 25%, 48%, 50%, and 76%, respectively. Merely 87 out of the total 1986 families with kebeles had improved cookstoves; the remaining households used 3-stone stove types. According to the study, the pyrolysis stove had the lowest fuel consumption rate and cooking time, while the 3-stone stove had the greatest fuel consumption rate and cooking time. The improvement stove reduced emissions, and the highest emission reduction stove was the gasifier stove, with a magnitude of 1.229 tons CO₂/HH/Year. Among cooking stoves, gasifier stoves have a great advantage in producing energy and biochar.

This study utilizes the orthogonal matrix analysis method to identify the lower levels of both conventional and unconventional emissions in engines powered by methanol gasoline, with the aim of optimizing gas emissions. Through the utilization of ANOVA, we were able to determine the key elements that impact the emissions of methanol gasoline from engines. Additionally, we validated the correctness of the experiment by employing the signal-to-noise ratio. The analysis focused on the combustion parameters of an engine that burns methanol fuel while maintaining low overall emissions. The accuracy of the numerical simulation was confirmed through the utilization of GT-power for numerical simulation and subsequent experimental validation. The findings suggest that when the engine operates at a load of 1200 rpm and 6 N m while consuming M85, there is a reduction in both conventional and unconventional emissions. M85 has a maximum cylinder pressure that is 18.7% more than pure gasoline. Conversely, pure gasoline demonstrates a power output that is 24.7% higher than M85. Additionally, M85 has a BSFC_e that is 22.71% higher than gasoline. The addition of a methanol-gasoline mixture can effectively reduce the engine's exhaust temperature.

Siloxane impurities in landfill gas (LFG) pose a significant challenge for downstream processing equipment used in energy recovery. This study investigated the adsorption capacity, cost, and environmental impact of five low-cost adsorbent materials: biochar, clinoptilolite, hydrochar, diatomaceous-earth, and crushed glass. Gravimetric analysis was used to determine the adsorption capacity of these materials for octamethylcyclotetrasiloxane (D4). The results were then used to conduct a technoeconomic analysis (TEA) and life cycle assessment (LCA), comparing the selected adsorbents with activated carbon (AC), a commonly used adsorbent for siloxane removal. The TEA revealed that the cost of LFG purification with clinoptilolite, biochar, and AC was $0.035, $0.034, and $0.033/m³, respectively, for the base case studied. The cradle-to-gate LCA showed that clinoptilolite had significantly lower carbon emissions compared with the other adsorbents, both per kg of D4 captured and per kg of adsorbent produced. The potential fate of siloxanes after adsorption was discussed, emphasizing the importance of proper treatment and disposal of spent adsorbents. Surface modification techniques were recommended to enhance the adsorption capacity and regeneration of clinoptilolite, potentially reducing cost and carbon emissions in LFG purification. These findings highlight the potential of low-cost adsorbents for sustainable LFG purification.

The treatment of Hanford tank waste is one of the most challenging environmental cleanup activities to date. To expedite the processing of liquid waste stored in underground tanks in Washington State it is necessary to remove the significant dose contributor, ¹³⁷Cs. Crystalline silicotitanate ion exchanger is currently used to remove ¹³⁷Cs from the aqueous phase of Hanford tank wastes in preparation for vitrification at the Waste Treatment and Immobilization Plant (WTP). Improving the understanding of potassium impacts on ion exchange behavior of Cs will help in the operation of a critical component of one of the most complex treatment processes in the world today. Optimization of this process can result in significant cost savings and less waste production. Toward this effort, a series of batch contact tests varied in potassium concentration were conducted to look at the impact of potassium concentration on Cs distribution. Experimental distribution ratios (K_d) were compared to the distribution ratios predicted using the ZAM model. A significant underprediction of Cs capacity in the presence of potassium was seen with the existing model. A revision of the equilibrium constants was determined and provided a statistically better fit for determining the Cs K_d values in tank waste matrices.