CL:AIRE (Contaminated Land: Applications in Real Environments), established to facilitate the demonstration of remediation technologies and research on contaminated sites around the UK, has been in operation now for 22 months. The CL:AIRE Board has ratified a total of five demonstration projects: two technology demonstrations and three research projects (see IEM April and October of last year for the first three). Here, the latest two.
Funded through EPSRC and industry and due for completion in early 2001, the project involves innovative methods for characterising bioactivity at contaminated sites.
The research will: (a) investigate contaminated soil at a representative former gasworks site and quantify the physical, hydrological and chemical characteristics and assess the transport of organic contaminants to groundwater; (b) evaluate in-situ microbial biodegradative activity using reverse transcriptase polymerase chain reaction (RT-PCR) techniques and the potential for enhancement assessed and tested; (c) incorporate the information on biodegradative activity into a modelling framework, in order to predict the long-term impact of current and enhanced in-situ bioremediation; and, (d) develop the model as a decision support system to provide guidance for bioremediation design for groundwater protection.
This project has joint funding through industry and EPSRC. Preparatory work has already started on site with the drilling of three monitoring wells. Each well has been completed with the installation of an innovative, multilevel monitoring system, which will allow the measurement of groundwater head and chemistry at seven discrete locations. This information will be used as input data to a 3-D numerical model of groundwater flow and contaminant mass transport.
The research will develop a general process model of natural attenuation of petroleum hydrocarbons and MTBE in dual-porosity aquifers. A combination of field, laboratory and modelling studies will be used to identify controls on the migration and degradation of BTEX and MTBE hydrocarbons. Novel stable isotope studies and molecular microbial analysis will be used to assess spatial and temporal variations in degradation, as a function of aquifer hydrogeology and contaminant distribution. Parameter values of processes and properties controlling natural attenuation will be determined, enabling the process model to be validated at field-scale. The key objectives are to: