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Showing 6 results for Leachate

P. Alimohammadi, N. Shariatmadari, M.a. Abdoli, H. Ghiasinejad, A. Mansouri,
Volume 8, Issue 2 (6-2010)

Hydrologic Evaluation of Landfill Performance (HELP) model is one of the most accepted tools to simulate

the hydrological attributes of landfills. Although some major deviations from real values has been reported about the

calculated results for leachate generation by HELP model but other researchers and/or engineers in practice have

used it in some places to estimate amount of leachate produced in the landfills. On the Other hand this model is

elaborated and mainly used in developed countries with the waste having low moisture content and also in climatic

conditions with high precipitation. This research investigated the applicability of the model in arid areas, by

construction of two 30m× 50m (effective horizontal length) test cells in Kahrizak landfill (longitude=51°, 20',

latitude= 35° 27' degrees), and monitoring the real leachate generation from each one. A set of field capacity and

saturated water conductivity tests were also performed to determine basic hydrologic properties of municipal waste

landfilled. A comparison was made between values calculated by HELP model and recorded values, shows that a

prediction of leachate on annual basis can be done by HELP model with acceptable accuracy but when the infiltration

of water to waste body increases due to leachate production, the model intents to underestimate water storage capacity

of the landfill, which lead to deviation of calculated values from real ones.

Nader Shariatmadari , Marzieh Salami, Mehran Karimpour Fard,
Volume 9, Issue 2 (6-2011)

The main task in the design and construction of impermeable liners in landfills is to block the migration of pollutants to the groundwater

systems or to reduce its rate to a reasonable amount. That is why environmental regulations force governments to construct engineered

waste dumps for waste management purposes. These liners are exposed to various types of chemical, biological, and physical processes

and are affected by the leachate which is produced from decomposition of waste materials accompanying methane gas. The leachate

includes a lot of components such as water and different types of salts. For this reason, the geotechnical characteristics of clay liners

which are evaluated in laboratories using distilled water or tap water might be far different from the representative sample of the in-situ

conditions. There are some evidences regarding the effect of these salts on the physical and mechanical properties of clay barriers which

could affect the long-term performance of these liners. Since the main criterion for impermeable bottom liners in landfills is their

hydraulics conductivity, the increase of this parameter could have a considerable environmental impact. This paper embraces the results

of a recent study on the effect of three inorganic salts, NaCl, CaCl2 and MgCl2 on some geotechnical properties of a common used clay

soil in impermeable bottom barrier in Kahrizak landfill, the main waste disposal center of the Tehran Metropolitan. Also the effect of

bentonite content by adding different percentage of this special clay mineral, 10 and 20 percent, on these properties was investigated.

Laboratory tests like liquid limit, compaction, 1D consolidation and free swell tests were performed for this purpose. Results indicated

that all of these salts could have a considerable effect on the geotechnical properties of the mixtures. The main reason of such effects is

the changes which occur in diffuse double layer of clay particles.

Sandro Machado, Mehran Karimpour-Fard, Miriam Carvalho, Orencio Villar, Atila Caldas,
Volume 12, Issue 3 (7-2014)

Municipal Solid Waste (MSW) materials are among the most complicated materials for geotechnical engineering as their composition includes an organic fraction, which suffers loss of mass over time, and a fibrous part, which acts as reinforcement, governing the MSW shear behavior. Because of these characteristics MSW can be described as a viscous material which shows time dependent behavior. Since the decomposition of MSW leads to gas and leachate generation, the changes in the MSW’s mechanical behavior could be linked to gas emission and leachate production from landfills. This paper deals with the characteristics of MSW materials to provide the necessary data for efficient and safe landfill design, construction and operation. The MSW physical characteristics such as composition, water content and organic content at varying ages, field and laboratory measurements of methane generation and leachate production, MSW compressibility behavior and its shear strength are covered. By presenting these data the authors hope to promote a better understanding of the mechanical behavior of MSW and provide useful data for use in landfill management tasks.
Amin Falamaki, Hossein Tavallali, Mahnaz Eskandari, Rezanejad Sharbanoo Farahmand,
Volume 14, Issue 2 (3-2016)

Soil contamination by heavy metals is a worldwide environmental challenging issue. Due to the industrial activities, a site located in North West of Shiraz (Fars Province, Iran) has the potential to be contaminated by different heavy metals. The objective of this study was to assess the effectiveness of dicalcium phosphate (DCP) and sodium tripoly phosphate (STPP) for immobilizing lead, copper and cadmium in contaminated soils. Leaching column tests performed on the soil without any stabilizing agent demonstrated a uniform leachate of metals in the effluent during the experimental period. After mixing DCP or STTP with the contaminated soils, the release of all three heavy metals through the effluent was ceased. The results further indicated that 0.1 to 0.2 percent by weight of these stabilizers is effective for immobilizing of applied metals through the experimental soil. Penetration of acid sulfuric solution with pH of 5 had no influence on stabilizing efficiency and almost whole the applied heavy metals seem to be immobilized through the soil media.

Nader Shariatmadari, Behnam Askari Lasaki, Hasan Eshghinezhad, Behzad Askari,
Volume 14, Issue 7 (10-2016)

The main purpose of this study is to investigate the influence of urban solid waste leachate on the mechanical properties of the soil. Order to provide a more accurate identification of the contaminated soils, Cylindrical specimens of the soil, according to the density curves with different initial conditions (different initial contamination levels) were prepared, then the soil specimens were loaded at different load levels using a direct shear testing equipment and a universal testing machine to apply axial compression on the specimens. By analyzing the results, the stress-strain and failure behavior of the soil specimens containing different percentages of the solid waste leachate was evaluated. The most important result was reducing the mechanical properties of the soil contaminated with different percentages of solid waste. The results of adding lower quantities of leachate, is far more significant compared to the received results from adding higher amounts of leachate.

Syed Abu Sayeed Mohammed, Sanaulla P.f, Ariif Ali Baig Moghal,
Volume 14, Issue 7 (10-2016)

In this study, the relative performance of two soils as a sustainable natural material in retaining the selected heavy metal ions, cadmium (Cd2+) and nickel (Ni2+), from aqueous solutions has been evaluated. Red earth soil (RS) and black cotton soil (BCS) originating from India, were selected and batch equilibrium tests including sorption kinetics and leaching studies were conducted. The experimental data was used to plot sorption isotherms, Langmuir isotherm was found to be more suitable than Freundlich isotherm for both the soils. Monolayer sorption capacity was calculated from Langmuir isotherm. Kinetic data was fitted on four models namely pseudo first order, second order, Elovich and intraparticle diffusion. Correlation coefficients obtained by all models fitted well in the following ranking: Elovich>Intraparticle diffusion > Pseudo second order> Pseudo first order. Based on extensive experimental data, it is concluded that the ranking on sorption was of the order Cd > Ni for both the soils and BCS exhibited relatively higher retention levels compared to RS.  It is further concluded that, BCS can be used as a substitute to filter material, RS a substitute to main liner material in attenuating Cd2+ and Ni2+ from an industrial landfill leachate.

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