| dc.description.abstract | Water is one of the most important drivers for human life and nature, and its availability often constitutes a limit on economic development and human welfare. Under a changing climate scenario, the variability of water supply is increasing while water demand is also expected to increase. Therefore, providing sufficient water supply at affordable rates will become one of the greatest challenges that humankind will face in the coming years. In fact, effective and innovative use of water resources has become one of the most active topics of research within the academia and the industry.
As a matter of fact, in the early 2000’s, a novel geoengineering technique for a microbial sealing process was performed by Deltares (formerly GeoDelft) in the Netherlands, to reduce leakage flow through dikes. After four years of research Deltares patented a method called BioSealing, which consisted of the injection of nutrients into the soil to stimulate the growth of naturally present micro-organisms (bacterial growth) in the subsurface, in an anaerobic environment. The converging groundwater flow transports these nutrients towards a leaking structure, where the formed biomass induces clogging and reduces the flow rate passing through the leakage.
In this study, the BioSealing technique developed by Deltares is presented as an environmentally friendly technique that uses naturally present microorganisms to seal the subsurface, in order to accumulate water on top of fractured bedrock. As a first proof of concept for this novel technology, a laboratory setup was designed and constructed to demonstrate the efficiency of this process. The setup was built under different conditions in a sand-filled PVC tank, which contained a simulated leak in a water-retaining PVC layer with a 5cm gap in its centre. A water flow was pumped onto the topsoil of the tank, in a two-day trial to simulate an artificial recharge (AR) process within the sandbox, assessing then how the setup performed.
The AR simulation proved that the experimental setup is suitable to conduct a BioSealing experiment, being able to monitor the most important soil parameters —matric potential, dielectric permittivity, volumetric water content, bulk electrical conductivity and pore-water electrical conductivity— to study the clogging effect in time.
This study developed a first prototype to use the BioSealing technique as an alternative and useful geotechnical application, thus contributing to the solution of an important societal issue, such as recurrent droughts in times where climate change is compromising our water availability. | |
