Sediment solution for Antwerp

The design for a mechanical dewatering plant will save over €7m per year, while delivering processing and sustainability benefits. The MWH solution requires only 20 ha of land to process the sediment, compared with 120 ha that would be required by a lagooning process: the alternative and standard solution. This saving is a significant benefit in Antwerp where land comes at a premium price. The total cost of the MWH Mechanical Dewatering solution (covering all costs, including depreciation over a 15 year period) is estimated as €26-29 per tonne dry matter, compared to a cost of €38-40 for lagooning.

As with other ports, Antwerp needs to dispose of huge amounts – in this case 600,000 tons dry matter – of harbour sediment each year, to maintain andimprove the navigation system for large vessels. Liv Duerinckx, senior project engineer, explains the approach: “Lagooning involves the removed sediment standing in large pools for a year to separate the solids and the water, before the solid content is removed and dumped at a suitable site. For Antwerp, the concept of lagooning has been replaced with a design for a mechanical dewatering system: the sediment will settle in pools for one week, then get moved to a separation and dewatering installation, where it is pumped into a chamber filter press that compresses out the water.

Additives are mixed in before the remaining, dense solid matter is removed to a stockpile.”