ADVANCED SITE DIAGNOSTICS FOR REMEDIATION AND CLOSURE

摘要

The fact that contaminants degrade a rates which can generally be classified as first order has created a "purgatory of the asymptote" for many responsible parties. This has lead to an active search for alternative means of dealing with the problem and one fair and feasible strategy has been the application of monitored natural attenuation (MNA). In order to better determine when MNA can be best applied as a treatment we and others have begun to introduced new lines of evidence for the existence of natural attenuation . In some cases the methods can also be applied to the understand the dynamics of movement of contamination and be used to provide rates of degradation.Advanced site diagnostics is a broad descriptive area that in our definition encompasses three areas of technology. The first is the use of molecular biological tools (MBTs) that can be used to characterize key organisms, their enzymes and the expression of those enzymes involved in biodegradation. In this way the existence and efficacy of the actual mechanisms of natural attenuation can be established without question ,building regulatory confidence in MNA as a remedy. A second fruitful area of technical application is the use is stable isotopes. By employing different aspects of this diagnostic, much useful information that can be developed, including but not limited to the fate of dissolved phase plumes and the absolute proof of natural attenuation. The latter is achieved, in some examples, by tracking the breakdown of a contaminant through the use of a labeled contaminant surrogates, or the incorporation of labeled carbon into microbial structures there by establishing natural attenuation. The third area of diagnostic advancement utilizes the latest is direct sensing technologies to not only better characterize sites but also establish impacts of in-situ treatment and illustrate the types and quantities of key organisms present on site.