A phosphor factory was located at the former Kuhlmann site in Zelzate, Belgium. As a residue, phosphogypsum was produced and dumped on the grounds of the plant. This has caused severe pollution of the site, which needs to be decontaminated. The process includes excavation of the contaminated soil and groundwater remediation. The polluted soil is being excavated and treated by a consortium of DEC-DI-JdN-Envisan. The groundwater which is mainly polluted with suspended solids and fluorine, is being cleaned by Purazur NV.
At the site, the run-off water and the groundwater have to be purified. In order to remove contaminants such as fluorine from the water, Purazur NV has designed an appropriate water treatment installation with a capacity of 20 m³/h.
The installation consists of a buffer, a coagulation/flocculation with Poly Aluminium Chloride (PAC) and a lamella separator. The settled silts are removed to a sludge dewatering. The overflow of the bottom residues is then treated in an active carbon sand filter, after which it is disposed on surface water.