Landfill Techniques

Remediation Hooge Maey (Antwerp, Belgium)

Every city or municipality used to have a domestic waste disposal site. Now Flemish waste management policy aims to minimise waste dumping as much as possible. Preventing waste, recycling or incinerating it and recuperating the energy are preferable. Yet Flanders will still have to maintain a certain disposal capacity for some time. The Antwerp disposal site Hooge Maey is one of those sites. DEC remediated two sites: the so-called zones A and B. One of them may be used later as a disposal site, the other is planned as a new industrial zone within the port area. At the Hooge Maey, Zone C is now being used as a domestic waste disposal site.

Zone A was an oversaturated area: drainage was impeded because the site was surrounded by motorway and railway embankments. In this zone, there were various contaminated spots, including a tar basin, an industrial sludge mass and two contaminated ponds. After remediation and raising, Zone A was designated for industrial use.

Zone B was an old sand pit filled with dredged sediment and then used as a disposal site for household waste, industrial waste and inert materials. Zone B would serve as an expansion zone for the current Hooge Maey disposal site on completion of the works.

The largest part of the project, 30 of the 39 hectares was part of Zone B. All excavated waste remained on the site and was buried within zone B, treated or untreated. Depending on the contamination found, different techniques had to be used. The lower capping of this zone B consisted of existing polder clay and uncontaminated dredging sediment.

Because of the former disposal activities, part of Zone B was already above the original surface level at the start of the work. At the peripheral zones of the site, a strip was excavated to the underlying clay layers. A capping layer was added to the slope that connects to the existing bottom layer. The capping layer consisted of a mineral water-inhibiting layer of 60 cm thick and a HDPE membrane, a drainage layer and a rooting layer.

A total of 300,000 m³ waste was moved. Suspicious and/or hazardous waste was studied case by case. Before the beginning of the actual remediation, a remediation storage was set up within Zone B to store any hazardous waste, treated or untreated.

The machines on site (cranes, bulls, dumpers, etc.) were all fitted with pressurised cabs to protect the personnel. During the work, monitoring was carried out continuously.