Remediating water, from the inside out
The EU-funded project ʹHigh efficiency in situ treatment technology for contaminated groundwaterʹ (HEISTT) is creating an innovative system to treat contaminated ground water, by injecting remedial chemicals into the subsurface. The aim is to remove cost-based entry barriers for those wishing to implement in situ oxidisation-based remediation. The proposed technology aims to develop a rapid and highly efficient method that makes use of ultrasonic-assisted injection technology to create a closely spaced grid of single-treatment wells. The remediation chemicals can then be introduced into the ground using a kind of sock made from permeable fabrics known as geotextiles. After extensive literature reviews, the first HEISTT prototype probe was fabricated; in laboratory-scale experiments, it is already demonstrating a reduction in the force required for insertion. Coupling it with an excavator and excavator-mounted vibrator piling head will enable much faster creation of wells. The manufacture of geotextile socks proved to be costly, even before they were filled. The HEISTT team have overcome this issue by designing a geotextile insertion system which allows the geotextile to be formed into tubes during insertion, and cut to the required length. This not only removes significant fabrication costs, but also reduces waste and lowers transport costs. Thanks to the better distribution of treatment chemicals, the HEISTT system will likely improve the speed of remediation treatment chemical installation and increase the rate of remediation. Importantly, it will also reduce costs and provide simpler and safer installation. All of these factors will make the technology more widely accessible. In addition, the technology has potential for use in other non-remediation situations: the installation of solar farms is being investigated as one such possibility.