In Situ Delivery (ISD™)
Automated recirculation equipment designed for groundwater extraction and re-injection, while delivering electron donor substrates, chemical oxidants, or surfactants on a site-wide basis.
A primary limitation of in-situ remediation processes (i.e. chemical oxidation, bioremediation) is the lack of contact between delivered amendments and the contaminants. Unfortunately, many pilot-scale and full-scale in situ processes are implemented using slug injections, which are often ineffective because they have minimal radius-of-influence, so they fail to maintain appropriate subsurface conditions or deliver the required mass of amendments. In order to overcome these limitations, ETEC has developed automated recirculation systems that can deliver liquid and slurry-phase substrates, nutrients, or chemical oxidants to the subsurface on a consistent, scheduled basis. The In Situ Delivery (ISD™) equipment platforms are fully automated and programmable allowing you to optimize delivery of remediation products based on your site-specific remediation needs.
Electron Donor Substrates
The ISD™ Equipment can be customized to deliver a wide-range of electron donor substrates, depending upon your choice. Substrates will be automatically mixed with the extracted groundwater and re-injected throughout the site to achieve maximum contact. The ISD™ equipment is designed specifically for delivery of ETEC’s CarbStrate™ electron donor substrate as part of our anaerobic bioremediation system, but can also be used to deliver ethyl lactate, oils, or other electron donor substrates.
Chemical oxidants (hydrogen peroxide, permanganate, persulfate) are used to oxidize a broad range of organic compounds. Because oxidant cost is very high, minimizing these costs via efficient subsurface injection is imperative. Recent studies show that slug injections of high-concentration oxidant solution are ineffective, unsafe, and can waste a significant mass of oxidant. The ISD™ equipment provides precise injection control of the volumes and concentrations of oxidants and catalysts, saving money while increasing contaminant destruction efficiency, and protects your field personnel from dangerous chemical reactions.
Surfactant Flushing and Hot Water Recirculation
The efficiency of pump and treat systems over time diminish greatly, leading to extended treatment timeframes. The automated delivery of surfactants can increase the amount of contaminants captured by the existing extraction system. The ISD™ equipment can move multiple pore volumes of surfactant-amended groundwater through the site to help encourage free-product and residual contaminant recovery. Any surfactant can be used, but we recommend our non-ionic PetroSolv™ biosurfactant for enhanced contaminant recovery. Hot Water recirculation is utilized for thicker product removal (i.e. No.6 fuel oil)