"In-situ groundwater remediation
with iron particles: Studies on long-term stability, reactivity and transport"The use of iron particles for in situ remediation of groundwater contaminations is a technology that has significant development potential but also a number of unresolved questions. In addition to questions regarding the reactivity and the long-term stability of the particles in the aquifer, the possibility to monitor the fate and transport and hence the mobility of the particles after injection is a major challenge. Several research projects have been and are conducted in VEGAS dealing with these questions. Moreover methods for monitoring are under development.
The investigations include batch experiments which provide investigations in a closed, controllable system under “optimal” conditions and allow to compare long-term stability of the various particles.
In the column experiments fate and transport of various iron suspensions can be investigated qualitatively and quantitatively. A special experimental column setup was designed in which the flow velocity, the concentration and the formulation of the suspension, the particle size distribution and the aquifer materials can be varied.
In addition to the column tests, a 3 D test setup was constructed to investigate the interaction of the different variables under “realistic” conditions and at least to be able to transfer the experimental data to field applications.
In cooperation with the Institute for Theory of Electrical Engineering at the University of Stuttgart a measurement technique was developed for the determination of the injected particles in the subsoil. The measurement method is based on the measurement of magnetic susceptibility. The technique is currently being further developed so that the spread of the colloids in the field and at least the success of a remediation can be demonstrated.
The investigations of the 3D scale so far show that for nano Iron injection a transport radius of two meters can be achieved if appropriate formulations are used. With such investigations the arrangement and number of injection wells for field applications can be determined.
The findings are the results of an EU research project AQUAREHAB and a BMBF-project NAPASAN. Based on these results. Two pilot sites are currently carried out or under preparation. Involving SMEs will help to stimulate the use and to push the market entry of this promising remediation technology in the practice. The main objective of R&D projects is the development of a cost-effective overall concept of exploration to remediation contaminations.
In the presentation an overview of the investigations and some results will be presented.