Sediment and Sludge Treatment

Mechanical sediment dewatering plant Nyrstar (fka Umicore, Balen)

During zinc production at the Nyrstar company (formerly known as Umicore), a residual product 'goethite' is released. This goethite sludge is stored in basins at the premises in Balen. The company no longer has any capacity to store this sludge, and another solution had to be found.

At a production level of 260,000 tonnes of zinc per year, Nyrstar Balen produces a total quantity of goethite of approximately 75,000 tonnes of dry matter per year. The process also yields 40,000 tonnes dry matter of neutralised flotation sludge per year.

Based on a BOOT contract, Nyrstar wants to tackle this problem. After an extensive selection procedure, DEC in joint venture was awarded this project: the outsourcing of the investment and the operation of a system for the compact stocking of goethite and the neutralisation sludge of Balen.

DEC built a new dewatering system, where both residual flows are compacted. The solid filter cakes are then disposed in the existing landfill on the site. To make maximum use of the existing dump capacity, historic sludge was also excavated and compacted to the maximum in the dewatering system.