http://yetl.yabesh.ir/yetl1/handle/yetl/19016 2026-04-05T07:47:32Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309905 Simulation of Landfill Reactors to Understand Hg Release via the Landfill Cover Soil Surface Zhengkai Tao; Yiqing Fan; Zhanao Lv; Dayong Xu Landfill is an unignorable emission source of atmospheric mercury (Hg), while the specific source of the released Hg via cover soil surface and Hg migration process remain undefined. Here, landfill simulation reactors were designed to simulate the anaerobic degradation of Hg-containing solid wastes in unsanitary landfills. The characteristics of landfill gas, leachate, and cover soils were investigated to clarify Hg migration and transformation process. Methane, carbon dioxide, oxygen gases, and pH level in leachate suggested that simulated Hg-containing solid wastes underwent the expected anaerobic digestion. During the anaerobic digestion, total Hg concentration in leachates and cover soils from the reactors with Hg addition in solid wastes was far higher than that from the control. Moreover, the total Hg concentration in cover soils increased with time, with even total Hg concentration in the topmost soils reaching 281.27  μg kg−1 on the 212th day. These results indicated that gaseous Hg0 can be generated in the waste layers during the anaerobic decomposition of solid wastes. The gaseous Hg0 could migrate to cover soils through diffusion and advection, while a portion of gaseous Hg0 can be adsorbed by cover soils. Therefore, it is concluded that the released Hg via cover soil surface is from Hg in both cover soils and solid wastes, and diffusion, advection, and adsorption play an important role in the Hg release process. These findings improve the understanding of the landfill Hg emission process and provide positive implications for Hg management in landfills. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309904 Hybrid Immobilization–Phytoremediation Approach for Constructed Wetlands Minimizing the Geoenvironmental Impact of Chromium-Contaminated Soil Nishida Avunhippuram; Sobha Cyrus; Sreedeep Sekharan Soil contamination by heavy metals is a global concern due to their enduring persistence and inherent toxicity. Constructed wetlands represent a cost-effective and dependable green alternative to traditional mechanical remediation systems. This study utilized a hybrid approach, employing Chrysopogon zizanioides (vetiver) root micro powder (VRMP) for chromium immobilization in contaminated soil, in conjunction with Coleus amboinicus (Indian borage) plants to enhance soil remediation efficacy. The findings propose an improved strategy for adoption in constructed wetlands. The bioavailability and phyto availability studies were carried out on unamended and contaminated soil amended with 1%, 5%, and 10% of VRMP. Column leaching studies were conducted using a custom-built setup, and batch investigations using the Toxicity Characteristic Leaching Procedure (TCLP) procedure were employed to assess the bioavailability. Phyto availability studies utilized Indian borage plants in greenhouse pot experiments. Increasing the amendment dosage from 0% to 10% led to a rise in pH from 3.06 to 3.5, an enhancement in organic matter content from 1.31% to 21.86%, and an augmentation in cation exchange capacity from 12.6 to 24.68  cmol/kg. Simultaneously, there was a reduction in electrical conductivity from 3,090 to 1,080  μS/m. These alterations contributed to the diminished mobility of chromium within the soil matrix. For contaminated soil amended with 10% VRMP, chromium immobilization was achieved at rates of 95.32% in the continuous flow leaching experiment, 90.84% in pore volume analysis, 98.6% in the pot leachate study without plants, 99.67% with plants, and 93.48% in the TCLP in comparison to the levels observed in the unamended contaminated soil. Likewise, 97.37% of chromium was sequestered by the application of 10% VRMP, resulting in significantly lower chromium accumulation in the Indian borage plant compared to the untreated contaminated soil. The outcomes from column experiments, TCLP extraction, phytoremediation, and phyto availability studies collectively suggest that the hybrid immobilization phytoremediation approach stands out as a promising method for remediating chromium-contaminated soil and the principle can be adopted on a large scale in constructed wetlands. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309903 A Novel Index Approach for Estimating Soil Contamination in Oil Fields Khaldoon T. Falih; Siti Fatin Mohd Razali; Khairul Nizam Abdul Maulud Oil pollution presents a major environmental challenge associated with oil and its derivatives, posing significant threats to contemporary society. The primary issue involves accurately identifying polluted areas, determining the most contaminated stations, and assessing the extent of pollution over time. Traditional indicators measure pollution based on individual elements, which creates ambiguity in evaluating overall pollution levels. This study introduces a novel approach that integrates all measured elements to provide a comprehensive assessment of pollution. The methodology employs the least squares method to assign weights to each element and establish a threshold limit for site evaluation. Concentrations of various pollutants were measured at 10 stations (S-1 to S-10) over 6 months (August–March 2022), with the highest levels observed for PAH (8.270), Co (3.398), PCB (1.340), Cd (3.994), As (1.851), and Se (2.046). Current methodologies (CI, PLI, mCD, IGeo, NIPI, AP, and EF) were applied to validate the new approach. The threshold limit was determined to be 14.168. Applying this approach revealed that the site exceeded the threshold limit during June, July, and August, with values of 18.074, 21.258, and 24.536, respectively, indicating significant pollution during these months. The proposed method proved effective in providing an accurate and flexible means of determining pollution levels. Future recommendations include incorporating additional elements and increasing the number of sampling stations to enhance the accuracy and reliability of the results. This comprehensive approach offers a robust framework for assessing and managing oil pollution in affected areas. 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4309902 Separation Performance and Structure Optimization of a Novel Corrugated Plate Separator Honghong Yan; Xiaoyu Li; Yahang Li; Hong Zhang In order to improve the performance of the wet dust removal corrugated plate separator of continuous shearer, a new corrugated plate structure is proposed in this paper. The numerical simulation of air and droplet two-phase flow in the corrugated plate was carried out by using the computational fluid dynamics method. The influence of different structural parameters on the demisting efficiency and pressure loss of the corrugated plate was studied. The results show that the corrugated plate spacing has the greatest influence on the overall performance. Combined with the orthogonal test method, the performance prediction and optimization model of the corrugated plate mist eliminator are determined. A new hybrid multiobjective dragonfly algorithm is proposed to maximize the demisting efficiency and minimize the pressure drop. The multiobjective decision process of the corrugated plate structure parameters is carried out, and the optimal geometric structure of the demister is determined. This study provides a valuable reference for improving the demisting efficiency and the reducing energy consumption of the corrugated plate demister, which is of great significance for wet dust removal in mines. 2025-01-01T00:00:00Z