In 1990, 4500 m3 of silty sand/soil contaminated with mineral oil (diesel) to a level of 1500 ppm was treated on-site (Port of Antwerp) at the request of the client.
On reviewing both the site and the scope of the project it was clear to Nordevco staff that the most cost effective and efficient approach would be to treat the soil in a modified soil pile/wet cell using the BactiDomus Technology and a bioreactor. The construction of a bioremediation system began with the leveling of the area and placement of an environmental liner to ensure that the treatment was contained within the site with no risk of collateral contamination (see diagram at end of report).
The contaminated soil was processed through a sieve to remove all large rocks. A rubber tired loader was used to place relatively thin layer of on the liner in order to avoid any puncturing of the liner. A layer of BactiDomus Technology (product 402), was spread over the soil. This pattern of alternating layers was continued until the design height of 4m was achieved. A retaining wall was placed around the pile once the construction was completed.
At the base of the soil pile, between the pile and the retaining wall, a trench was constructed and was lined with the excess environmental liner. This trench was used as a catchment for the water that drained from the soil pile. The trench water was designed to flow into a two chamber bioreactor composed of two concrete chambers. The first chamber was used both as a sedimentation chamber and as a reservoir while the second chamber was designed to be used as an aerated bioreactor. A mixture BactiDomus Technology product 208 and product 401GG were added to the bioreactor.
The treated water exiting the treatment chamber was then re-injected on to the top of the pile. This treated water carried with it some of the BactiDomus Technology microorganisms back to the pile. This allowed for some passive treatment of the contaminants in the pile itself, while the bioreactor actively biodegraded the contamination washed from the soil into the water.
Port of antwerp oil spill soil remediation project case study