Hydrogeochemical assessment of the sorption properties of heavy metals in the areas of the impact of solid waste landfills on groundwater

Summary

The fundamentals of the method for predicting the spread of heavy metals in the areas of groundwater pollution by leachate from solid municipal waste landfills are stated. The analysis of the leachate quality of municipal solid waste landfills and the applicability of statistical and empirical estimates of the sorption coefficient of heavy metals is carried out. The limited applicability of statistical estimates for analyzing the distribution of highly mineralized leachate is shown. Based on the method of geochemical simulation, a model has been developed for determining the exchange coefficients between the dissolved and solid phases, i. e. sorption coefficients. The results of determining the sorption coefficient for a wide range of cations are presented with regard to the conditions of natural water displacement by the leachate from solid waste landfills. The developed method can be used to estimate the impact of municipal solid waste landfills on groundwater quality, to predict the spread of heavy metals in the area of potential waste impact, to carry out works within the framework of EIA (Environmental Impact Assessment) and LEPM (List of Environmental Protection Measures), to develop systems for engineering protection of groundwater from pollution. The proposed model can serve as a basis for its further improvement with account of the processes of formation of stable organic metal complexes in leachate and complexation on the hard rocks.

Key words

ion exchange , heavy metals , geochemical modeling , cation sorption , municipal solid waste landfill

The method of calculating heavy metal release from the layer of water body bottom deposits

Summary

The basics of the method of predicting heavy metal distribution between water and solid phases of bottom deposits in water bodies is outlined. Compared to other models of calculating heavy metal distribution between bottom deposits and void water the developed methodology takes into account the ongoing geochemical processes at the improved level with the use of advanced methods of geochemical modeling. An example of calculating heavy metal distribution under the conditions of the chemical composition of the solution changing with the use of advanced calculation methods in PhreeqC 2.18 program code is presented. The method can be used for the following tasks: geological mapping of the pollution of bottom deposits with heavy metals in water reservoirs and lakes; evaluation of the impact of bottom deposits on the chemical composition of water in water reservoirs and lakes; evaluation of the possible elimination of bottom deposits pollution or their immobilization and other measures of mitigating their impact on the water quality; evaluation of bottom deposits removal during dredging and also for solving the problem of their further utilization; evaluation of the possible instantaneous release of heavy metals from polluted bottom deposits and other emergency situations.

Key words

suspended substances , ion exchange , heavy metals , bottom deposits , geochemical thermodynamic sorption model , cation sorption