A tracer test was performed from 18/10/2010 to 25/10/2010. The Hydrogeology Group (GHS CSIC-IDAEA) coordinated this task, with 35 people (among undergrad and grads students, professors, researches, technicians and administrative personnel) participating in the preparation, injection and sampling campaign. The result will improve the knowledge of the physical and chemical properties of the aquifer under the infiltration pond.
During a first part of the experiment, 10 conservative tracers, commonly used in groundwater studies, where injected in the aquifer (anions, cations and dyes). The pumped flow was around 80 m3/h, and the total volume pumped was approximately 13.400 m3.
Parallel to this first part, an additional test where performed where non conservative tracers were injected, allowing bio stimulation of the aquifer, through the addition of ethanol, nitrate and phosphorous in an observation well close to the pumping well. The analysis of the nitrate and phosphorous isotopes will allow the determination of the microbiological activity in the aquifer, which is a key factor in the removal of organic micropollutants.
During next weeks the results will be analyzed and they will be applied in the design of an organic layer that will cover the infiltration basin.