SIMULATION OF DIFFUSION PHENOMENA OF CHLORINE ION THROUGH SOIL USING CELLULAR AUTOMATON METHOD

Abstract

Soil and ground water contamination has been spread due to the utilization and effluent of harmful materials from industrial factories or the illegal dump of poisonous gas weapon. By recent land development works for housing and city-reconstruction, the soil contamination is actualized, proposing it as a social problem. The law to prevent the soil contamination has been enforced from March, 2003 to promote the legal countermeasures against the soil contamination in Japan. Correct conjecture of soil contamination was required before the cleaning-up or the restoration of contaminated soil. The boring research was sometime done, but the accurate grasp was hard because of economic reason. It was general that information was multiplied by the numerical analysis of equations to govern the soil contamination. Then, the numerical analysis was paid much attentions to develop. However, when natural phenomenon was estimated using the numerical analysis to obtain highly accurate results, more complicated equations related to the phenomenon should be composed and solved. Moreover, the initial and boundary conditions should be established more sophisticatedly, otherwise simple conditions sometime led large errors. Actually, it was very hard to elucidate the phenomenon of contaminated materials in a complicated ground circumstances. For example, whole situation of the arsenic contamination at Kamisu-shi, Ibaraki, Japan, which appeared 2002 fiscal year, was not grasped until the present time, though the boring research was carried out. In the present study, cellular automaton method (CA), which was one sort of computer program, was applied to develop the simulation system for diffusion of soil-contaminated materials. Applying the CA to the diffusion simulation of soil-contaminated materials, it was expected to calculate rather simply the complicated phenomena by means of no construction of the governing equations and smaller parameters. As first attempt to develop the calculation system, diffusion simulating model for chloride ions, which was able to hold rather stable condition, was investigated to verify the applicability of the CA to the simulation of soil-contamination.