This work shows the application of an innovative procedure that is able to simultaneously identify the release history and the source location of a pollutant injection in groundwater using a dataset obtained experimentally. The methodology follows a geostatistical approach and it requires a preliminary delineation of a probably source area. The dataset was provided through an experimental installation developed at the hydraulic laboratory of the University of Parma (DICATeA). The equipment represents a 2-D unconfined aquifer controlled through two constant head levels (upstream and downstream); it consists of a Plexiglas sandbox filled with a porous medium (1 mm glass beads). An injector was placed inside the porous medium and sodium fluorescein salt was used as tracer during the tests. The standard test consists of releasing a constant and known concentration with a variable flow rate. The injection rate and the mean flow rate inside the sandbox are stored by means of a data acquisition system, meanwhile the concentration distribution inside the sandbox is observed through the processing of side wall images collected by means of a digital camera. The digital camera and the sandbox are placed in a dark room lightened by blue light in order to excite the fluorescein and easily evaluate the concentration distribution. A Matlab routine was developed to cut and to correct images by a projective transformation in order to obtain pictures with same size and orientation. Each pixel of the image has known coordinates on the sandbox. After a calibration process, the relationships between the luminosity of the emitted fluorescence and the tracer concentration have been identified in each pixel of the picture and consequently in each point of the domain. Initially a series of simple tests (with constant injection) were carried out with the aim at validating the experimental equipment comparing the observed data to those collected through the images, such as mass balance or mass flow rate. Once that the equipment was considered reliable, the tracer was injected with a variable flow rate in order to test and validate a geostatistical procedure that it is able to simultaneously recover the release history and the source location with a dataset provided under known and controlled condition. 20 concentration values at different times, obtained from the photographic technique, of 2 monitoring points were used to recover the flow rate injected in the porous media in time. A numerical model was developed to support the procedure, in particular, considering a constant injection, it allowed to identify the transfer functions between the source and the monitoring points. At first only the true source was considered and the injected flow rate was well recovered. Then the release history was recovered simultaneously for 4 potential sources (one true and three false). The geostatistical approach showed at the true source the actual release history and null concentration at the other sources. This demonstrated the capability of the method and the reliability of the experimental equipment.

Recovery the release history and source location of a pollutant in groundwater using data collected in laboratory / Zanini, Andrea; Cupola, Fausto. - ELETTRONICO. - H13F-1413:(2013). (Intervento presentato al convegno AGU Fall Meeting 2013 tenutosi a San Francisco nel 9-13 Dicembre 2013).

Recovery the release history and source location of a pollutant in groundwater using data collected in laboratory

ZANINI, Andrea;CUPOLA, Fausto
2013-01-01

Abstract

This work shows the application of an innovative procedure that is able to simultaneously identify the release history and the source location of a pollutant injection in groundwater using a dataset obtained experimentally. The methodology follows a geostatistical approach and it requires a preliminary delineation of a probably source area. The dataset was provided through an experimental installation developed at the hydraulic laboratory of the University of Parma (DICATeA). The equipment represents a 2-D unconfined aquifer controlled through two constant head levels (upstream and downstream); it consists of a Plexiglas sandbox filled with a porous medium (1 mm glass beads). An injector was placed inside the porous medium and sodium fluorescein salt was used as tracer during the tests. The standard test consists of releasing a constant and known concentration with a variable flow rate. The injection rate and the mean flow rate inside the sandbox are stored by means of a data acquisition system, meanwhile the concentration distribution inside the sandbox is observed through the processing of side wall images collected by means of a digital camera. The digital camera and the sandbox are placed in a dark room lightened by blue light in order to excite the fluorescein and easily evaluate the concentration distribution. A Matlab routine was developed to cut and to correct images by a projective transformation in order to obtain pictures with same size and orientation. Each pixel of the image has known coordinates on the sandbox. After a calibration process, the relationships between the luminosity of the emitted fluorescence and the tracer concentration have been identified in each pixel of the picture and consequently in each point of the domain. Initially a series of simple tests (with constant injection) were carried out with the aim at validating the experimental equipment comparing the observed data to those collected through the images, such as mass balance or mass flow rate. Once that the equipment was considered reliable, the tracer was injected with a variable flow rate in order to test and validate a geostatistical procedure that it is able to simultaneously recover the release history and the source location with a dataset provided under known and controlled condition. 20 concentration values at different times, obtained from the photographic technique, of 2 monitoring points were used to recover the flow rate injected in the porous media in time. A numerical model was developed to support the procedure, in particular, considering a constant injection, it allowed to identify the transfer functions between the source and the monitoring points. At first only the true source was considered and the injected flow rate was well recovered. Then the release history was recovered simultaneously for 4 potential sources (one true and three false). The geostatistical approach showed at the true source the actual release history and null concentration at the other sources. This demonstrated the capability of the method and the reliability of the experimental equipment.
2013
Recovery the release history and source location of a pollutant in groundwater using data collected in laboratory / Zanini, Andrea; Cupola, Fausto. - ELETTRONICO. - H13F-1413:(2013). (Intervento presentato al convegno AGU Fall Meeting 2013 tenutosi a San Francisco nel 9-13 Dicembre 2013).
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2751513
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact