To the editor:
Subject: Response to comment from Dr. [Ian] Peggs regarding spark testing on page 8 in the October/November 2009 issue of Geosynthetics, which was in response to “Geosynthetics in the construction of a Southern California subsurface biofilter cell system,” published in the August/September 2009 issue.
The authors appreciate and agree with Dr. Peggs’ comments regarding the spark testing. The purpose of the authors’ article was to highlight the application of the many geosynthetic materials in this unique project, and the sentence regarding spark testing was inaccurately stated. Several nondestructive tests, such as spark, vacuum, and air were used on the geomembrane seams during the construction.
The biofilter cell has been operational for more than one year and has provided valuable insights into the removal of selenium and nitrate from surface water using the bioreactor technology. The authors would like to thank the many interested individuals who have contacted us regarding the biofilter cell concept.