Large-Scale Plant for Wastewater Treatment and Production of Marketable Salt

The plant designed by EBNER is part of a package of measures by the customer for wastewater reduction at several plants. These measures represent the largest single investment in the customer’s history across Europe and are of utmost importance due to high media and politics interest. Having worked with EBNER for several decades, the customer trusted EBNER’s expertise for this plant as well. This allowed EBNER to undertake its first project in large-scale plant construction.

The resulting wastewater is first evaporated in a three-effect evaporation crystallization plant, crystallizing salt. A multi-effect preheating was implemented to ensure minimal primary energy consumption in the form of steam.

The third stage of the plant is so large (evaporator diameter 6.8m) that it was duplicated. The other components of the plant also posed a special challenge. For example, the heater of the second stage, weighing about 120 tons, was the heaviest apparatus ever manufactured by EBNER in one piece.

Complex Salt Processing

After the evaporation crystallization plant, the resulting suspension is fed into four sequential agitator vessels, each with a volume of 250m3, where further salt crystals are precipitated and existing ones grow.

The largest part of the suspension is then sent to a single-effect flash evaporation, where vacuum is applied to evaporate water, lowering the temperature of the suspension.

This is followed by the final step in the EBNER-supplied plant. Here, in a two-effect cooling crystallization, the suspension is further cooled. The cooling media are both cooling water and refrigeration brine from a refrigeration machine.