New Construction of an Industrial Wastewater Treatment Plant in the Metal Industry

Cause

Today, Deutsche Nickel GmbH produces semi-finished products made of nickel and nickel alloys at its Schwerte site. The production wastewater produced there is treated together with wastewater from another company in the company's own central wastewater treatment plant and then channelled into the municipal sewage system.

Process

Wastewater collection and buffering

The acid concentrates and, separately, the alkaline wastewater and rinsing wastewater from the pickling process are channeled into 2 new double-walled pump sumps. From here, the wastewater is pumped into 2 MABs, which have both a mixing and buffering function.

Batch treatment

The wastewater is then chemically treated in the two batch tanks. After filling the batch, sulphuric acid is added as required for decomplexation. Milk of lime is then added until a pH value of max. 11 is reached. Flocculant is then added to achieve good flocculation properties. This is followed by a reaction and settling time in order to achieve a reaction of the hydroxides. The clear water is then drawn off and channeled to the gravel filter.

Post-treatment of clear water

The clear water is first neutralized and further purified via gravel filters and ion exchangers. The primary goal of these steps is to reduce heavy metal concentrations to below the threshold limits for indirect discharge.The final inspection is carried out and the treated wastewater is discharged into the sewerage system of Deutsche Nickel.