IJsselmonde: mineral oil, naphtalene, PAHs and creosote ***

In-situ remediation technique: (Enhanced) natural attenuation, aerobic

Project name: IJsselmonde: mineral oil, naphtalene, PAHs and creosote *** Case submitted by: BioSoil Contact: Mw. C. v.d. Steenoven Address: Nijverheidsweg 27, 3341 LJ Hendrik Ido Ambacht Telephone number: +31 (0)78 - 682 01 40 Email-address: c.vandesteenoven@biosoil.com

Country: The Netherlands City/region/county: IJsselmonde Rotterdam, Zuid-Holland (future) use of location: Light industrial, residence Built-up location during the active remediation phase?: No

In situ saneringstechniek: (Enhanced) natural attenuation, aerobic

Explanation technique: There was a creosoting facility located on the site, causing a serious contamination of the soil. A pilot remediation has been executed which is funded by NOVEM, the Municipality of Rotterdam and the Dutch Railways (NS). The aim of the pilot was to demonstrate how this location could be cleaned in-situ. The pilot location had a surface area of about 200 m2 and thus in fact the entire source of the contamination. Also other remediation techniques applied?: Yes, at the centre of the contamination (the location of the creosoting boilers) basement remains are removed and the contaminated soil is excavated to the groundwater (about -1.5 m). Also creosote is extracted from the filters in the centre of the contamination. After care needed?: Yes, after the pilot, full sclae remediation started. Rationale for the chosen technique: Because of the depth of the contamination (up to -12 m) and its spreading beyond the boundaries of the site, excavation was not possible. Removal of the contamination, followed by biological degradation of the mobile fraction of the contamination, in accordance with municipal policy of Rotterdam, a sufficient result should be acquired for the redevelopment of the site.

Treated contaminant(s): Mineral oil, PAKs, naphtalene and creosoto Contaminant phase: Soil/pure product and groundwater Size contamination: 15.000 m3 Depth contamination: 2 - 12 m below

Soil type: Mainly sand with clay layers Saturated/unsaturated zone?: Saturated zone Permeability: > 0,1 m/day, based on field data Flow velocity or gradient groundwater: Low

Remediation goal: Removal of the mobile fraction of the contamination. The PAH concentration in the groundwater should be below the T-value. This accounted for the '16 of EPA', for the 6 PAH's not included in the '10 of VROM' T-values were determindes based on interpolation. Remediation goal achieved?: No, the pilot was successfully. After the pilot, the in-situ remediation has started (still in progress). Initial and final concentration and load removal: Contamination 1:PAH's initial concentration: 120.000 µg/l final concentration: 50 µg/l total initial load: remark [kg] total final load: <0,1 [kg] Contamination 2: mineral oil initial concentration: free product final concentration: < 50 µg/l total initial load: remark [kg] total final load: < 0,1 [kg] Active remediation phase: 1995 until present day (remark). Passive remediation phase: The passive phase is not yet completed. Total costs passive/after care phase: Total costs active phase:

Problem owner: Hulsinga Altona Contractor: BioSoil Remediation plan: BioSoil R&D Remediation research: IGN Competent authority: Gemeente Rotterdam Contact information stake holders: BioSoil Vastgoed adopted ownership of the site

Lessons learned: Research showed a creosote contamination at the site. The groundwater was heavily polluted with naphthalene and the ground was also contaminated. The execution of the pilot revealed much higher contamination values in soil (17,000 mg / kg PAHs). After partial excavation the concentrations were 6000 mg / kg PAHs and 10,000 mg / kg mineral oil. At greater depth a DNAPL was observed above a clay layer under a sand layer of approximately 1.5 m. The DNAPL stretched beyond the borders of the remediation site under some planned houses. The DNAPL appeared to be mobile during the implementation of the pilot. Before the start of the remediation research was conducted with the camera probe of Deltares. It appeared that the DNAPL consisted of mobile droplets that occurred in a band of 30 cm thick at 1.5 m above the clay layer. This resulted into a product layer of 1.5 m in the monitoring wells, which makes it relatively easily to be extracted. It was evident, that in such cases a pilot and research with a camera or ROST-sounding is needed to make a clear picture of the problem. Remarks: The pilot was conducted in the period 1995 to 1997. In consultation with the Municipality of Rotterdam the in-situ remediation started in 1999. BioSoil has taken the responsibility for the site and the contamination. The remediation is still in progress. The DNAPL underneath the neighboring houses was removed and the soil is clean. The contamination is greatly reduced, but the area where the creosoting facility was is still not fully cleaned in accordance with the remediation objective. It is difficult to estimate the further process, because after the removal of free product (DNAPL), the subsequent delivery will stop, which leads to decreasing concentrations in the groundwater.

Related techniques: (Enhanced) natural attenuation, aerobic

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