Remediation of DNAPL through Sequential In Situ Chemical Oxidation and Bioaugmentation
Abstract
The principal benefit of in situ chemical oxidation (ISCO) using permanganate (MnO4)is that it aggressively enhances dissolution and destruction of the target contaminants within a relatively short period of time (i.e., months to years); however, the cost-benefit of this technology diminishes as the mass of target chemicals decreases. The most effective application of ISCO consists of rapid destruction of the readily accessible target chemical mass within the source area, although it can also be coupled with a less costly, in situ remediation mass removal technology such as in situ bioremediation (ISB). The main objectives of this project was to assess the technical feasibility of sequential application of these technologies and to identify the optimal timing of the transition from ISCO to ISB. The principal results of the project include: 1. Electron donor addition (ISB) after ISCO resulted in partial biodegradation of trichloroethene (TCE), with complete biodegradation observed after bioaugmentation; ? 2. At the field-scale, ISB did not increase the mass flux of chloroethenes after ISCO; 3. The precipitated manganese dioxide produced by MnO4 - reduction, which can oxidize some organic compounds, did not abiotically degrade any of the chloroethenes or ethene; 4. Manganese dioxide (MnO2) greatly increases the electron donor demand above that typically required to reduced the dissolved constituents (e.g., oxygen, nitrate, sulfate, and the target chloroethenes) during ISB; 5. MnO2 can be dissolved by the activity of Mn(IV)- reducing bacteria, that appear to preferentially utilize hydrogen and inhibit the activity of dechlorinating microorganisms (i.e., Dehalococcoides, which use hydrogen as their sole electron donor); and 6.The limited cost assessment indicated that there was a significant cost and schedule advantage for the sequential treatment strategy over using pump and treat or ISCO alone.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2009
- Accession Number
- ADA512826
Entities
People
- Dave Major
Organizations
- Geosyntec Consultants (United States)