Two former landfills in Veenendaal where mined to be able to develop the area into a housing area. The waste and the excavated soil was largely reused.
Options to expand the town Veenendaal was mainly possible on the south-eastern side. Unfortunately, two landfills, Benedeneind and Engelage, were located in the middle of the housing development area and thus created a major obstacle for this housing development.
A remediation study concluded that complete removal of 54,000 m3 of waste along with separation of material into partly reusable fractions was the preferred and the most economic option. The increase in the price of land, together with a subsidy from the province of Utrecht, made the complete removal economically viable.
A vertical cut off wall of High Density Poly Ethylene (HDPE) was installed. The groundwater level was lowered. Extracted groundwater was slightly contaminated with mineral oil. This groundwater was treated on-site (aerated lagoons) and then pumped into the nearby sewer system.
In total, 80% of the excavated waste was treated in a separation process resulting a reusable fractions within the city development project (soil, sand and rubble). The remainder (20%) was transported to a sanitary landfill where landfill tax was paid. This remainder consisted mainly of plastic, car tyres and asbestos. Polluted underground was removed and transported to an off-site soil cleaning facility.
• Municipality of Veenendaal
• Province of Utrecht (subsidy for the project))
• Regional water board
• Roseboom (contractor)
Total project fee amounts 4.500.000 euro (including landfill tax).
The increase in land value together with a provincial subsidy funded the project.Three person staff from Grontmij were involved in project preparation and remediation supervision. From the contractor > 20 people were involved.
Evidence of success
• In total 80% of the excavated waste was extracted for re-use;
• Certain hot spots in the underlying soil were remediated completely;’
• Future land development (land value increase) paid for the remediation.
The following challenges where encountered:
• High natural groundwater table;
• presence of asbestos in the waste for working conditions and the re-use potential of the different fractions. New legislation during the remadiation lead to a negative impact on the overall reuse of the waste.
Potential for learning or transfer
This practice is very suitable in regions where there is high land pressure and the land value can be potentially high. As the landfill mining project also allows reuse of materials, it also generates some revenues and reduces the costs for primary materials. It contributes to a Circulair Econmy and reduces CO2 emissions.
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