Analysis of Contaminant Transport in Porous Media

All industrial manufacture and human consumption of goods and resources produce waste. By ‘waste’ it is meant not only the ‘useless’ by-product of organism or manufacture, but also any effluent, chemical, compound or substance, which if discharged into the environment may give rise to contamination problems. One of the most important problems facing society today is how we can disposed of our waste in ways which do not endanger human health and the environment.

It was not until the 1970’s that environmental legislations designed to protect the environment such as the licensing of waste disposal were introduced in Australia. Since then, the state governments in Australia have continually sought to enhance environmental protection by legislation. This is exemplified by the Environmentally Hazardous Chemicals Act 1985 and the Environmental Offences and Penalties Act 1989 enacted in New South Wales and the Environment Protection (Amendment) Act, 1989 in Victoria.

In line with current expectations on environment protection, there is a move now in Australia to introduce a regulatory framework that will impose stricter control over the disposal of all forms of waste (Parker and Sadlier, 1992). If this comes into being, there will be greater emphasis on the North American and European practice of waste containment rather than conventional methods of waste disposal such as the ‘dilute and disperse’ of waste leachate into the groundwater system. As a result, if the natural underlying soils do not already provide sufficient barrier at the chosen disposal sites there will be increasing use of engineered systems. The long term performance of these waste facilities, often for periods of many
decades, will have to be carefully assessed in relation to the effectiveness of the design of barriers. It is desirable to do this by the use of mathematical models as experimental modelling is usually both costly and limited in its ability to predict over long span of time.

This paper presents a background of contaminant transport processes of a single species in a single phase system and show some results of a boundary element method developed for assessing potential long term contaminating effects of waste storage, disposal and leakage.