WHY DIDN’T IT WORK? THREE CASE STUDIES OF APPARENT IN-SITU CHEMICAL OXIDATION FAILURES AND WHAT THE SITES WERE SCREAMING TO REVEAL!

摘要

In an episode of the old TV series Kung Fu, the elderly blind Grand Master asked, “Grasshopper, do you not hear the cricket walking at your feet?” Grasshopper looking down, saw the cricket and asked, “Master, how is it that you can hear the cricket walking?” The Master answered with a question, “Grasshopper, how is it that you do not?” Until the advent of the controlled in-situ chemical oxidation process, much of the information or misinformation about applied field (in-situ) remedial technology was an extrapolation from laboratory experimentation, geology texts or other “not necessarily hands-on expert sources.” Biological systems worked under certain conditions but, were so benign and slow that success could only be measured as a degree of contaminant disappearance or the evolution of metabolic gasses; an analytical process difficult to monitor in the field. Conversely, conventional Fenton oxidation was so boisterous that the subtle voices of the site were drown out by the vigorous tenor of the reaction. This paper explores how a combination of oxidizer formulating, application technique and the more often than not, subtle reactions of the site to these two procedures, reveals the most opportune remediation approach. Case 1. DNAPL, DNAPL, where’s the DNAPL? It wasn’t there at all. Find out how adsorbed hydrophobic contaminants can harbor dense organic solvents such that, groundwater analysis would give the impression of the presence of free product. Case 2. The concentrations of BTEX are only around two (2) mg/L. Why won’t the groundwater clean up? Case 3. Some sites just never clean up. How tracing the oxidation reaction across a site revealed a continuing source of site recontamination and the consequences. In all of these cases, it was subtle hints that led to the solution of the problems.