When applying remediation products to soil and groundwater at a contaminated site, the main goal is to degrade or break down the contaminants of concern. While that is the primary focus, planning for what happens to the site following remediation is also important. Careful consideration must take place not only for meeting secondary groundwater goals, but also for leaving the aquifer usable. Remediation professionals should not “salt the Earth” in exchange for successful remediation.
At ETEC, we have carefully formulated our products to not only be industry leading in bioremediation, but also to leave as little as possible behind upon project completion.
- For petroleum bioremediation, mechanically produced oxygen and nitrate are used as electron acceptors to drive microbial metabolism of the petroleum contaminants. The products of aerobic bioremediation are carbon dioxide and water. The by-products of nitrate-supported bioremediation ultimately are nitrogen gas, carbon dioxide, and water.
- For chlorinated solvents, it is reassuring that most bioremediation products being applied are food-grade. ETEC’s CarBstrate, for example, is food-grade, though it does contain ammonia-nitrogen. Fortunately, the nitrogen is readily assimilated by microbes and does not pose groundwater concern at project completion. It is important to note that with any reductive treatment, certain metals like iron, manganese, and arsenic, may become more soluble as ORP becomes negative. Additionally, the conversion of sulfate to sulfide can also affect the water quality following treatment.
A key differentiator of ETEC’s remediation approach is its phased application strategy, which enables tapered dosing aligned with the declining contaminant mass as a site progresses toward cleanup. At the beginning of a remediation project, a “sledgehammer” dose is often required to overcome the electron acceptor demand threshold. As the project continues, product dosing can be tailored during monthly, quarterly, or intermittent injections to match the remaining contaminant mass. Adjusting product application dosing is very important as a site approaches low cleanup standards. A low contaminant mass makes it very easy to over apply products and end up with exceedances above secondary groundwater limits. However, in ETEC’s 30+ years, only a handful of sites have had lingering issues at completion. One example was a site with a well side-gradient to the treatment area less than 5 mg/L above the limit for nitrate…that was in the middle of a golf course fairway!
Remediation professionals should approach treatment planning with care and responsibility, keeping in mind principles like the Hippocratic Oath: first, do no harm.
In contrast, there are a lot of remediation treatments that leave behind high pH, sodium, manganese, sulfate/sulfide, metals, and the contaminants themselves. Other treatments involve “putting in as much product as the ground will accept”, making overapplication very easy. Remediation professionals should approach treatment planning with care and responsibility, keeping in mind principles like the Hippocratic Oath: first, do no harm.
ETEC takes pride in a remediation philosophy that prioritizes both effectiveness and environmental stewardship. Our products are designed to minimize residual impact, and our dosing strategies are carefully tailored throughout the project’s lifecycle. With a multi-decade track record of successful cleanups and minimal post-project issues, we remain committed to leaving sites better than we found them.