Simulation of Contaminants Transport in Groundwater From Nickel Mining Waste Dump Southeast Sulawesi

The irregularities of nickel resource mining in Indonesia cause many serious environmental problems. Piles of leftover rocks on nickel mining waste dumps have the potential to be a source of heavy metal seepage into the water. This study was conducted to assess the impact of nickel mining in the Langgikima Subdistrict of the North Konawe Regency of Southeast Sulawesi Province. The focus is to assess the migration of hexavalent chromium (Cr6+) and iron (Fe) using MT3DMS to model the transport of solutes. The study's goal was to identify cr6+ and Fe concentrations in waste dumps and predict the spread of contaminants over a 20-year period of time. XRF (X-Ray Fluorescence) is done to determine the content of elements and minerals in rocks. Toxicity Characteristics Leaching Procedure (TCLP) is performed to estimate the concentration of Cr6+ and Fe in waste dumps. AAS (Atomic Absorption Spectrophotometer) to find out the content of Cr6+ and Fe in surface water and land water samples. The results showed the highest concentrations of Cr6+ of 0.0462 mg/L and Feat 0.8709 mg/L. Simulations without compacted clay coatings, Cr6+ and Fe contaminants could be transported consecutively by 2.7 km and 2.42 km while simulations used compacted clay layers with a hydraulic conductivity of 1 × 10−9 m/s of Cr6+ and Fe contaminants could be transported consecutively by 0.412 km and 0.467 km. It can therefore be concluded that heavy metals in the remaining rock piles from the waste dump can be transported into groundwater, and the action of using a compacted layer of clay must be taken to prevent contaminant migration into groundwater.

The Influence of Industrial Waste on the Magnetic Properties of Salt-Affected Soils from Two Soda Ash Manufacturing Sites

The aim of this study was to characterize the impact of soda ash manufacturing on the magnetic properties of soils located in the agricultural landscape in north-central Poland. Two study sites were chosen: Mątwy (SM) and Janikowo (SJ). Highly saline soils with halophyte communities were selected in order to develop an understanding of the relationship between salinization of water–soil interface and the potential contamination risk of the environment. Basic chemical and physicochemical properties of topsoil (0–25 cm) and water (surface and groundwater) samples from five locations were characterized. The characteristics of soil contamination were based on the content of selected metals, magnetic properties and salinity indices. Potential routes of contaminant migration (air and water fluxes) were analyzed. High magnetic anomalies of technogenic origin were revealed in the studied soils. A statistically confirmed relationship between high magnetic susceptibility and the content of selected metals (Co, Ni, Cu, Zn, Ba, Pb and Mn) showed the high utility of magnetometric techniques in soil research (diagnosis of soil transformation and contamination during technogenic impact). Three potential factors influencing contaminant migration were revealed: highly saline ground and surface water, eolian transport of fine-grained mineral fractions from waste ponds and atmospheric deposition of coal combustion products.

Migration of the Industrial Wastewater in Fractured Rock Masses Based on the Thermal-Hydraulic-Mechanical Coupled Model

Industrial wastewater may have a long-time effect on the environment and human life as it goes underground and causes serious pollution continuously. To have a well understanding of the migration of such wastewater is a basic task for industrial wastewater treatment as well as industrial design. To study the migration mechanism of industrial wastewater in rock formations, the governing equations such as mechanics, seepage, heat, and mass transfer are reviewed, referenced, and proposed. The thermal (T)-hydraulic (H)-mechanical (M) coupled model of the multimedia of matrix-fault and matrix-fracture-fault is established. The influence of the fault and the fractures on the pressure distribution and contaminant migration is analyzed. The influence of fault length, width, dip angle, permeability, and temperature of wastewater on contaminant migration is parametrically studied. The following results can be obtained. (1) The fracture quantitively affects the concentration distribution, while the fault dominates the concentration distribution and contaminant migration. (2) The migration of the contaminants can be geometrically divided into 3 zones along the direction of the fault: the saturation zone, the rapid diffusion zone, and the concentration decrease zone. (3) There is a peak of the concentration along the bottom of the model. The position of the peak is the projection of the endpoint of the fault. (4) The fault length has the most significant effect on contaminant accumulation. The temperature of the wastewater has the minimum effect on the contaminant accumulation. (5) The accumulation of concentrations can be divided into 2 stages, the slow growth stage (before 20 years) and the rapid growth stage (after 20 years). The main channel of contaminant migration in the slow growth stage is a fault. During the rapid growth stage, the contaminants penetrate through the rock matrix as well as the fault.

Comparison of CFD and Multizone Modeling from Contaminant Migration from a Household Gas Furnace

In Central and Eastern Europe, a growing popularity of gas heaters as the main source of heat and domestic hot water can be observed. This is the result of new laws and strategies for funding that have been put in place to encourage households to stop using coal and replace it with cleaner energy sources. However, there is a growing concern that gas furnaces are prone to malfunction and can be a threat to occupants through CO (carbon monoxide) generation. To see how a faulty gas furnace with a clogged exhaust may affect a household, a series of multizone and computational fluid dynamics (CFD) simulations were carried out using the CONTAM software and CFD0 editor created by the National Institute of Standards and Technology (NIST). The simulations presented different placements of the furnace and ventilation outlet in an attached garage. The results showed how the placement influenced contaminant migration and occupant exposure to CO. It changed the amount of CO that infiltrated to the attached house and influenced occupant exposure. The results may be used by future users to minimize the risk of CO poisoning by using the proper natural ventilation methods together with optimal placement of the header in the household.

About Two-dimensional Mathematical Model of Contaminant Migration in Unsaturated Catalytic Porous Media with Traps

This paper proposes an approach for the computer simulation of complex physical problem of contaminant migration through unsaturated catalytic porous media to the filter-trap. The corresponding mathematical model in the two-dimensional nonlinear case is presented. The model includes detailed considerations of the moisture transfer of saline solutions under the generalized Darcy’s and Cluta’s laws in different subregions of soil. The numerical solution of the boundary value problem was found by the finite difference method and proposed the algorithm for computer implementation. The proposed algorithm may be used for creating software with effective risk assessment strategies and predicting the cleaning and further useful use of the soil massifs.