|Geologische aspecten van de walberging van baggerslib|
Fobe, B. (1999). Geologische aspecten van de walberging van baggerslib. Geol. Belg. 105(3-4): 223-228
In: Geologica Belgica. Geologica Belgica: Brussels . ISSN 1374-8505, more
In the Flemish Region, a yearly amount of about 4.000.000 m3 contaminated dredge sludge has to be deposited on land. The selection of disposal sites also depends on the geological considerations. If a use for the sand is found, disposal pits can be constructed at the time and in the area of the dredging works. Disposal on sandy deposits requires protective measures for groundwater quality. Therefore, sites where the bottom protection can be provided by a natural clay layer are preferred. Lateral protection is achieved by surrounding the site with a bentonite wall over the whole thickness of the sand layer. Several sludge disposal sites are located in the «Flemish Valley» deposits (20 m of sand of Pleistocene age) where these overlay a clay layer. Another way of disposal are overdepths under docks. This method is applied in the Waasland Port (left bank of the Port of Antwerp) where sludge is stored in a sand layer between the dock bottom and the Boom Clay. Due to the hydrogeological conditions (mainly the stable water level in the dock), the dispersion of pollutants is strongly limited.