In-situ soil remediation completed within one year

In-situ remediation can be quick – faster than many people think. Orvion has designed an in-situ remediation plan for a site in Bilthoven and has provided their environmental expertise. This remediation was completed within one year; the intervention value in soil and groundwater was amply achieved.
A gas station used to be present at the location. Because the location was going to be used for residential construction, the soil had to be cleaned up. The soil contamination was first excavated to a depth of approximately 3 meters. The deeper soil and groundwater were then remediated by biosparging, with a small amount of ozone added to the injected air.

With only biological treatment, the remediation period was estimated at 1.5 to 2 years. Because this would take too long for the future residents of the homes that were to be built, it was decided to add a small amount of ozone to the injection air. This was estimated to reduce the remediation duration to nine months. The remediation was carried out by Bunnik Milieu, T&K service, Hoste Milieutechniek and Orvion.

The oxygen concentrations in the groundwater soon increased after the start of the remediation (see attached graph). Nutrients were also dosed so that the bacteria could grow quickly and effectively break down the oil/aromatics contaminants. The drop in the graph (April 2019) was caused by a short malfunction in the system.
Before the start of the remediation, the concentration of mineral oil and aromatics in all 8 monitoring wells was above the intervention value (3,000 µg/l of mineral oil on average). On June 21st, about 6 months after the start of the remediation, the concentrations had already fallen below the intervention value in all monitoring wells. The average mineral oil concentration was reduced to 80 µg/l, a decrease of 97%. Subsequently, the concentration of oil was also determined in 20 soil samples. These all met the intervention value, with 16 samples even below the detection limit (<20 mg/kg ds). These good results show that in-situ remediation can also quickly lead to results. Do you also want to remediate in-situ quickly and effectively? Contact us to discuss the possibilities!

Marc van Bemmel is an Environmental Technologist. He established Orvion in order to develop and apply sustainable biological techniques. He has a great fascination with nature and likes to demonstrate how powerful it can be, how we can learn from it and how we can use natural processes in a meaningful and harmonious way.

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