The Efficacy of Oxygen Release Compound: A Seven Year Review

摘要

Oxygen Release Compound (ORC~(~R)) is proprietary formulation of intercalated magnesium peroxide that releases oxygen slowly and facilitates the aerobic degradation of a range of environmental contaminants including petroleum hydrocarbons, certain chlorinated hydrocarbons, ether oxygenates and nitroaromatics. The history of ORC's introduction and acceptance represents a model for the evolution of an innovative technology. This statement conies by virtue of the fact that since 1994 ORC has been used on over 6,500 sites worldwide and has been the subject of an extensive body of literature. This technology, which can be further characterized as one that employs a "time release electron acceptor", has now been clearly established as a sensible strategy for engineering accelerated bioattenuation on sites where design, capital and management intensive options are either undesirable or contraindicated. ORC can be configured as a permeable reactive barrier, applied as a broader plume treatment and emplaced post-excavation as part of the backfill. Some guidelines for using ORC have also emerged. It is contraindicated at sites where the BOD/COD load, seasonal or otherwise, is excessive or poorly understood, i.e., the technology is best applied to dissolved phase plumes and moderate levels of residual NAPL once the majority of the source is removed by more mechanically intensive means. With regard to the range of compounds that can be addressed, ORC was first used for the remediation of BTEX and TPH groundwater contamination and other applications have since been made, with variable results, on an array of other aerobically degradable compounds such as VC, PCP, PAHs and MTBE. With respect to MTBE, as early as 1996 consultants using ORC noticed that MTBE concentrations decreased at a higher than expected rate. Working on this foundation, in concert with published evidence that ethers are aerobically biodegradable, additional field experiments demonstrated that oxygen can indeed enhance the remediation of MTBE; a concept that has since been verified in other quarters.