scholarly journals Landfill Final Cover Systems Design for Arid Areas Using the HELP Model: A Case Study in the Babylon Governorate, Iraq

2018 ◽  
Vol 10 (12) ◽  
pp. 4568
Author(s):  
Ali Chabuk ◽  
Nadhir Al-Ansari ◽  
Karwan Alkaradaghi ◽  
Abdulla Al-Rawabdeh ◽  
Jan Laue ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Shallow Groundwater ◽  
Systems Design ◽  
International Standards ◽  
Arid Areas ◽  
Cover System ◽  
Capillary Barriers ◽  
Cover Systems ◽  
Negative Effect ◽  
Cover Design

The main purpose of selecting proper designs for landfills is to accommodate quantities of waste without having a negative effect on the surrounding environment and human health. The Babylon Governorate (province) in Iraq was taken as an example of an arid area with very shallow groundwater and where irregular waste disposal sites had developed that had not been subject to international standards when they were selected for landfill use. In the current study, the suggested design for landfills is a base liner and final cover system. In this suggested design, the final cover system allows for three scenarios. The first scenario considers an evapotranspiration soil cover (ET) (capillary barriers type), the second scenario is a modified cover design of “RCRA Subtitle D”, and the third scenario is a combination of the first and second scenarios. The HELP 3.95 D model was applied to the selected landfill sites in the governorate to check if there was any penetration of the leachate that might in future percolate from the landfill’s bottom barrier layer in arid areas. The results from the suggested landfill design showed that there was no leachate percolation from the bottom barrier layer using the second and third scenarios. For the first scenario, however, there was a small amount of leachate through the bottom barrier layer in the years 2013 and 2014.

Simulation of Final Cover Systems in Mitigating Landfill Gas Migration

2014 ◽  
Vol 587-589 ◽  
pp. 886-891
Author(s):  
Thaveesak Vangpaisal
Keyword(s):  
Barrier Layer ◽  
Landfill Gas ◽  
Element Model ◽  
Effective Control ◽  
Gas Migration ◽  
Gas Flux ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System

Landfill cover systems have to serve as a hydraulic barrier as well as a gas barrier. The ability of multilayered cover systems to mitigate landfill gas migration was assessed. A finite element model, SEEP/W®, was used to simulate the landfill cover system. It was found that gas advective flux through the single GCL barrier was highly dependent on the differential gas pressure across the cover system and the conditions of soils above the barrier layer. The change from wet to dry condition resulted in the increase of gas flux up to 3000 times. Gas flux variations were much lower for the case of a single CCL. The use of a geomembrane on top of a CCL or a GCL significantly increased the effectiveness of the barrier layer in mitigating gas migration, particularly in a dry climatic condition. Furthermore, the change of the cover conditions had less effect on gas flux through a composite cover system than gas flux through a single barrier cover system. For the effective control of landfill gas migration, the cover system must be maintained at the high moisture content conditions.

Formation, Distribution and Transport of Shallow Groundwater in Arid Areas, China

2011 ◽  
Vol 28 (1) ◽  
pp. 67-73
Author(s):  
Hong-yi ZHANG ◽  
Fan-jiang ZENG ◽  
Hai-tang AN
Keyword(s):  
Shallow Groundwater ◽  
Arid Areas

Seismic stability analyses of reinforced tapered landfill cover systems considering seepage forces

2018 ◽  
Vol 36 (4) ◽  
pp. 361-372 ◽  
Author(s):  
Afshin Khoshand ◽  
Ali Fathi ◽  
Milad Zoghi ◽  
Hamidreza Kamalan
Keyword(s):  
Parametric Study ◽  
Limit Equilibrium ◽  
Practical Method ◽  
Seismic Stability ◽  
Design Parameters ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System ◽  
The Stability

One of the most common and economical methods for waste disposal is landfilling. The landfill cover system is one of the main components of landfills which prevents waste exposure to the environment by creating a barrier between the waste and the surrounding environment. The stability and integrity of the landfill cover system is a fundamental part of the design, construction, and maintenance of landfills. A reinforced tapered landfill cover system can be considered as a practical method for improving its stability; however, the simultaneous effects of seismic and seepage forces in the reinforced tapered landfill cover system have not been studied. The current paper provides a solution based on the limit equilibrium method in order to evaluate the stability of a reinforced tapered landfill cover system under seismic and seepage (both horizontal and parallel seepage force patterns) loading conditions. The proposed analytical approach is applied to different design cases through parametric study and the obtained results are compared to those derived from literature. Parametric study is performed to illustrate the sensitivity of the safety factor (FS) to the different design parameters. The obtained results reveal that parameters which describe the geometry have limited effects on the stability of the landfill cover system in comparison to the rest of the studied design parameters. Moreover, the comparisons between the derived results and available methods demonstrate good agreement between obtained findings with those reported in the literature.

scholarly journals Understanding the Role of Shallow Groundwater in Improving Field Water Productivity in Arid Areas

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3519
Author(s):  
Xiaoyu Gao ◽  
Zhongyi Qu ◽  
Zailin Huo ◽  
Pengcheng Tang ◽  
Shuaishuai Qiao
Keyword(s):  
Soil Water ◽  
Soil Salinity ◽  
Water Productivity ◽  
Shallow Groundwater ◽  
Irrigation Scheduling ◽  
Crop Growth ◽  
Groundwater Depth ◽  
Groundwater Salinity ◽  
Arid Areas ◽  
Soil Water And Salt

Soil water and salt transport in soil profiles and capillary rise from shallow groundwater are significant seasonal responses that help determine irrigation schedules and agricultural development in arid areas. In this study the Agricultural Water Productivity Model for Shallow Groundwater (AWPM-SG) was modified by adding a soil salinity simulation to precisely describe the soil water and salt cycle, calculating capillary fluxes from shallow groundwater using readily available data, and simulating the effect of soil salinity on crop growth. The model combines an analytical solution of upward flux from groundwater using the Environmental Policy Integrated Climate (EPIC) crop growth model. The modified AWPM-SG was calibrated and validated with a maize field experiment run in 2016 in which predicted soil moisture, soil salinity, groundwater depth, and leaf area index were in agreement with the observations. To investigate the response of the model, various scenarios with varying groundwater depth and groundwater salinity were run. The inhibition of groundwater salinity on crop yield was slightly less than that on crop water use, while the water consumption of maize with a groundwater depth of 1 m is 3% less than that of 2 m, and the yield of maize with groundwater depth of 1 m is only 1% less than that of 2 m, under the groundwater salinity of 2.0 g/L. At the same groundwater depth, the higher the salinity, the greater the corn water productivity, and the smaller the corn irrigation water productivity. Consequently, using modified AWPM-SG in irrigation scheduling will be beneficial to save more water in areas with shallow groundwater.

Effect of Pretreatment on Allicin Degradation and Color Change in the Dehydration of Garlic

2019 ◽  
Vol 62 (5) ◽  
pp. 1293-1298
Author(s):  
Zusongying Zhao ◽  
Klein E. Ileleji ◽  
Diana M. Ramirez Gutierrez ◽  
Zhian Zheng
Keyword(s):  
High Temperature ◽  
Broad Spectrum ◽  
Cold Water ◽  
Color Change ◽  
Processing Method ◽  
International Standards ◽  
Solar Drying ◽  
Negative Effect ◽  
Temperature Pretreatment

Abstract. Allicin is the most important active ingredient in garlic because it gives garlic its unique flavor and has a broad spectrum of antibiotic activities. It is also an indicator of garlic product quality. Color can also be used to determine the quality of dehydrated garlic. The allicin content and color of dried garlic are influenced by the processing method, such as pretreatment, and the drying parameters, primarily temperature. To explore the factors that affect the allicin content and color of dried garlic, this study compared the differences in allicin content and color for common pretreatment methods and drying temperatures (35°C for 22 h, 55°C for 12 h, and 75°C for 5 h, to simulate open-sun drying, solar drying, and factory drying, respectively). The results showed that high-temperature pretreatment had a negative effect on the color and allicin retention of dried garlic slices. Cold-water washing and 55°C drying temperature are recommended to produce good garlic color and preserve the allicin content (2.78 mg g-1) to meet both national and international standards. Keywords: Allicin, Color change, Dehydration, Drying, Garlic.

scholarly journals The Ecological Relationship of Groundwater–Soil–Vegetation in the Oasis–Desert Transition Zone of the Shiyang River Basin

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1642
Author(s):  
Le Cao ◽  
Zhenlong Nie ◽  
Min Liu ◽  
Lifang Wang ◽  
Jinzhe Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Soil Salinity ◽  
Shallow Groundwater ◽  
Water Source ◽  
Northwest China ◽  
Soil Salinization ◽  
Arid Areas ◽  
Important Indicator ◽  
Vegetation Growth

Groundwater is an important ecological water source in arid areas. Groundwater depth (GWD) is an important indicator that affects vegetation growth and soil salinization. Clarifying the coupling relationship between vegetation, groundwater, and soil in arid areas is beneficial to the prevention of environmental problems such as desertification and salinization. Existing studies lack research on the water–soil–vegetation relationship in typical areas, especially in shallow groundwater areas. In this study, the shallow groundwater area in Minqin, northwest China, was taken as study area, and vegetation surveys and soil samples collection were conducted. The relationships between vegetation fractional coverage (VFC) and GWD, soil salinity, soil moisture, and precipitation were comprehensively analyzed. The results showed low soil salinity in the riparian zone and high soil salinity in other shallow-buried areas with salinization problems. Soil salinity was negatively correlated with VFC (R = −0.4). When soil salinity >3 g/kg, VFC was less than 20%. Meanwhile, when GWD >10 m, VFC was usually less than 15%. In the areas with soil salinity <3 g/kg, when GWD was in the range of 4–10 m, VFC was positively correlated with soil moisture content (R = 0.99), and vegetation growth mainly depended on surface soil water, which was significantly affected by precipitation. When GWD was less than 4 m, VFC was negatively correlated with GWD (R = −0.78), and vegetation growth mainly relied on groundwater and soil water. There are obvious ecological differences in the shallow-buried areas in Minqin. Hence, it is reasonable to consider zoning and grading policies for ecological protection.

scholarly journals Quantification of the inevitable: the influence of soil macrofauna on soil water movement in rehabilitated open-cut mine land

2015 ◽  
Vol 2 (2) ◽  
pp. 853-870 ◽  
Author(s):  
S. Arnold ◽  
E. R. Williams
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Mine Waste ◽  
Soil Development ◽  
Soil Macrofauna ◽  
Functional Dynamics ◽  
Cover Systems ◽  
Crucial Information ◽  
Mine Sites ◽  
Cover Design

Abstract. Recolonisation of soil by macrofauna (especially ants and termites) in rehabilitated open-cut mine sites is inevitable. In these highly disturbed landscapes, soil invertebrates play a major role in soil development (macropore configuration, nutrient cycling, bioturbation, etc.) and can influence hydrological processes such as infiltration and seepage. Understanding and quantifying these ecosystem processes is important in rehabilitation design, establishment and subsequent management to ensure progress to the desired end-goal, especially in waste cover systems designed to prevent water reaching and transporting underlying hazardous waste materials. However, soil macrofauna are typically overlooked during hydrological modelling, possibly due to uncertainties on the extent of their influence, which can lead to failure of waste cover systems or rehabilitation activities. We propose that scientific experiments under controlled conditions are required to quantify (i) macrofauna – soil structure interactions, (ii) functional dynamics of macrofauna taxa, and (iii) their effects on macrofauna and soil development over time. Such knowledge would provide crucial information for soil water models, which would increase confidence in mine waste cover design recommendations and eventually lead to higher likelihood of rehabilitation success of open-cut mining land.

Cars and the environment: A new approach to assessment through ISO 14001 certification of the car process

2003 ◽  
Vol 217 (1) ◽  
pp. 31-40 ◽  
Author(s):  
F Orecchini ◽  
D Sabatini
Keyword(s):  
Life Cycle ◽  
Production Process ◽  
Environmental Sustainability ◽  
Point Of View ◽  
International Standards ◽  
Iso 14001 ◽  
Pollutant Emission ◽  
Negative Effect ◽  
Set Up ◽  
Iso 14001 Certification

To change the negative effect of traffic increase and to diminish noxious pollutant emission and environmentally harmful consequences of the car's life cycle, innovative tools and radically changed approaches are needed. The present proposal of assessing the car and its environmentally related technological and functional factors as part of the entire mobility production process shows the applicability of ISO 14001 standards to the entire car process and could be a concrete aid to reaching the current European and international objectives and strongly encouraging environmentally friendly car design, manufacturing and lifestyles. The car influences the environment during every stage of its life cycle. This paper analyses and demonstrates the real possibility of certifying, through ISO 14001 standards, instead of an industrial site or organization, a car process. The car process is the part of the mobility production process implemented in car use. Environmental management systems (EMSs) have been developed to improve the environmental performance of organizations towards the diffusion of sustainability in industrial production. The ISO 14000 series of international standards are the most important reference for eco-management of any type of organization. The two target groups involved in the car process environmental certification procedures set are manufacturers/suppliers on the one hand, interested in environmentally compatible new markets and products, and clients/users on the other hand, interested in testing benefits and problems of the EMS set-up and general environmental sustainability behaviours. The car model analysed for the case study application is the Toyota Prius, from the environmental point of view one of the best on the market, precursor model of the next-generation electric hybrid vehicles.

scholarly journals Operational validation of HYDRUS (2D/3D) for capillary barriers using data of a 10-m tipping trough

2018 ◽  
Vol 66 (2) ◽  
pp. 153-160
Author(s):  
Klaus Berger
Keyword(s):  
Lower Boundary ◽  
Contaminated Sites ◽  
Hydrological Models ◽  
Threshold Values ◽  
Capillary Barrier ◽  
Capillary Barriers ◽  
Cover Systems ◽  
Free Drainage ◽  
Using Data ◽  
Interesting Alternative

AbstractCapillary barriers are an interesting alternative component for cover systems of landfills and contaminated sites. Provided they are sufficiently validated, soil hydrological models could be fast and powerful tools for the dimensioning of capillary barriers. Outflow rates measured in a 10 m long tipping trough for one material combination and two slopes from stationary periods were compared to simulation results of HYDRUS (2D/3D), Version 2.05. The measured outflow rates show a typical pattern with slope-dependent threshold values indicating the efficiency of the capillary barrier. This flow pattern could not be reproduced with HYDRUS (2D/3D) that for different input setups produced smooth patterns without thresholds. The input setup was varied for different soil hydraulic models (van Genuchten-Mualem vs. Brooks-Corey), homogeneous and heterogeneous transport domains (no scaling vs. stochastically distributed scaling factors considering the Miller-Miller similitude), different HYDRUS versions (standard vs. alternative; i.e., with material properties assigned either to finite element nodes or finite elements, respectively), and different lower boundary conditions (seepage face vs. free drainage). Differences between measured and simulated outflow patterns could be caused by the measurements, the application of the model, or by the model itself. The van Genuchten-Mualem model may not be suitable to describe the soil hydrological relationships of these particular materials. The reason for the mismatch, however, could not be identified yet.

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