Efficient remediation of contaminated sites through DNBA

With traditional pump-and-treat remediation, predictability and cost efficiency often proved elusive. A study commissioned by the LUBW found that the projected remediation timeframes of this method are frequently exceeded because target values are not achieved. Continuing such remediation until the final target values are reached can pose a serious risk to budget certainty—and may even become a dealbreaker for well-planned land use projects. In some cases, the cost of recovering one kilogram of TCE (trichloroethene) can even exceed the maximum price of gold—unless the remediation approach is switched to a microbiological in-situ method such as DNBA.

This makes the success of Ginger HPC INTERNATIONAL all the more significant: in 47 completed remediation projects, microbiological in-situ groundwater remediation using DNBA (Dynamized Natural Bio-Attenuation) has been successfully applied as an alternative to pump-and-treat. Not only were the projected remediation timelines not exceeded—they were often shortened. Clients saved costs in the double-digit millions and reduced remediation durations by one to two decades compared to pump-and-treat methods. In addition, microbiological in-situ remediation is more environmentally friendly and sustainable, as it requires little to no electricity and produces no waste requiring disposal.

Why is DNBA more efficient, and how does it work?

Following a DNBA feasibility study, an initial injection was carried out using an adapted consortium of site-specific bacteria, along with specially developed substrates and nutrients, into existing groundwater monitoring wells.

This initiated a multi-stage process: within a few months, a reducing and anaerobic environment was established in the groundwater. This first reduced Cr(VI) to insoluble Cr(III), which then became irreversibly fixed within the mineral aquifer (the rock layer that conducts groundwater). Subsequently, within the same biochemical in-situ environment, chlorinated solvents were almost completely degraded—eliminating their risk to groundwater and human health.

Although a remediation period of more than seven years had originally been planned, the DNBA in-situ remediation was officially completed after just 4.5 years in coordination with the authorities. Water samples showed that contamination levels had been reduced, in some cases below detection limits. The remediation targets were therefore not only met but exceeded.

Compared to traditional pump-and-treat remediation, DNBA in-situ remediation in this case resulted in savings of approximately €12.7 million. According to Dr. Frank Karg, this level of cost-benefit efficiency—provided a DNBA feasibility study can be conducted—is guaranteed for all DNBA projects carried out by Ginger HPC INTERNATIONAL.