The influence of fluctuations in the groundwater table on Monitored Natural Attenuation

摘要

Because of the interaction between the dissolution of components and the distribution of the residual NAPL-phase in the pores multiphase-fluid flow and the contaminant transport have to be investigated considering the effect of hysteresis. The natural processes are influenced by the interactions between the air-, water- und contaminant phase, e.g. by changing supply of molecular oxygen. The solubility of organic compounds varies due to time the groundwater stays inside the contaminated area, as well. Summarising a remediation by Monitored Natural Attenuation requires the following site characterization information: 1. Laboratory and field investigation of soil mechanical and chemical properties of the soil and of the hydrological, chemical and biological properties of the fluids e.g. locations of potential receptors, direction of ground water flow and hydraulic conductivity. 2. Modelling of the processes running in the soil and groundwater. 3. Validation of the numerical processes by small and large model tests in the laboratory and in-situ and evaluation remedial processes. 4. Appropriate monitoring program, based on the principals of the observational method, which is a well known and successful in classic soil mechanical approach (deep excavations, slopes, tunnelling, high loaded foundations. 5. Checking the estimated natural processes. However the interaction between the multiphase-fluid flow and contaminant transport have to be considered to estimate the effectiveness of natural attenuation.