M. van der Wijk, P. Stook & J.C.N. van der Pal
Proceedings of the 14th International Peat Congress
land-remediation, natural-capping-of-the-landfill, volgermeerpolder
Theme V. Restoration, rehabilitation and after-use of disturbed peatlands
The Volgermeerpolder is a former dumpsite of 105 hectares, near Amsterdam in a marshy polder with shallow groundwater, open water and peaty soils. It was used as a landfill for domestic and industrial waste. This included large amounts of chemical waste, making it one of the most severely contaminated areas in Western Europe.
The severely polluted landfill was considered a ‘chemical time bomb’. After the Volgermeerpolder closed in 1981, the local authorities took 20 years to plan and action remedial measures. The remediation works started in 2001. Only in 2006 it was discovered that no groundwater pollution was detected in the surrounding marshy polder, it was concluded that the deep peaty soils surrounding the landfill acted as a natural barrier that prevented spreading of contaminants. The decision was taken that for remediation of the Volgermeerpolder it would be sufficient to cover the landfill, and that a complete isolation of the waste by means of a steel pile wall around the dumpsite and a bottom liner would not be required. This ‘saved’ around EUR 150 million.
During the remediation, the Advisory Combination Volgermeerpolder (ACV) found the peat soil surrounding the Volgermeerpolder to function as a ‘carbon filter’, which prevented spread of organic pollutants. To avoid replacement of a standard cover in the long run, ACV developed a surprisingly simple and effective concept: the ‘natural cap’. This concept consists of a gradual, functional replacement of the standard cover (of soil and a synthetic liner) by a natural layer of living, organic material.
The ‘natural cap’ is a surprisingly simple and effective concept with great potential for large- scale land remediation. It is considered a sustainable and effective alternative for standard remediation solutions and thus a valuable contribution to cost-effective remediation of a vast number of landfills and mine tailing deposits all over the world.