Volgermeerpolder: natural capping
The 100 hectares of the Volgermeer polder has a six-kilometre circumference. After the Second World War it was used as a municipal waste dump. In 1980 ten’s of thousands of barrels of chemical waste were discovered that were dumped there, including pesticides and dioxins from Philips Duphar.
A decision was made not only to isolate the polder but also to create a new nature area/recreation area on top, resulting in the biggest and one of the most complex remediation and land development projects in the Netherlands. The contaminated soil will be covered and the polder will have to be monitored for all eternity. A top lining of 2 mm HDPE will be applied to the entire area in combination with a landfill as drainage system. On top of that a new, predominantly moist, animate layer will be applied, forming the fundaments of a unique Sawa-waterway-system. To create a vulnerable ecosystem, depending of a complex watersystem integrated with the surrounding area, the full integration of technical and landscape design was required. This solution requires 2,5 million cubic metres of soil, and is mainly originating form the new metro line project in Amsterdam. The realisation of a moist nature and the reuse of excavated soil are reducing the cost of bringing in soil significantly. In this way two benefits are realised: at the lowest possible cost you create a safe and pleasant new environment at the vicinity of the city of Amsterdam.
Special attention was given to the health, safety and hindrance
At the start of the project in 2001 the technical feasibility of the proposed remediation measures are evaluated in a pilot. In the pilot the following aspect are evaluated;
- several techniques to isolate the heavily contaminated sludge in the existing waterways with underwaterliners
- spreading of heavily contaminated percolate and the influence of soil works on to this
- health and safety aspect ( exposure to contamination) of labour force on-site and the neighbouring population
- required thickness of soil layers to gain geotechnical stable condition given the fact that the Volgermeer is located in an swampy area
- the possibilities to realise the remediation construction with common soils originating from infrastructure project instead of the use of production sand
On the basis of the results of the pilot the design and tender documents were drafted. Special attention was given to the health, safety and hindrance aspects of the neighbourhood. During the project a total of 2 million m3 of earth has been moved.
On April 19th 2011 the remediated site was opened by His Royal Highness Prince Willem-Alexander van Oranje.
Thanks to the implementation of effective remediation measures, the soil has been cleaned up and the risks have been eliminated