A long-established, German-based, international company dealing in surface coating materials contacted Färber & Schmid in October 2017. As a result of altered compositions of the electroplating process chemicals (higher proportion of complexing agents and organic substances), it became increasingly difficult to comply with the required heavy metal limit values.
Although an evaporator had already been installed for the alkaline zinc/nickel rinse waters and the remaining wastewater was treated using a 2-stage treatment process, problems became increasingly common, in particular with zinc and chromium (III).
To begin with, laboratory tests were carried out at the customer’s premises with various heavy metal precipitants from the existing F&S product range, and the current 2-stage process was adapted to the 2-stage DUALmEx®-process from F&S.
In mid-January 2018, the first field trials were conducted under the guidance of F&S. By using a heavy metal precipitant developed specially for the customer – with the name Diplexin XP-40 – all problems have, since the beginning of 2018, already been solved. The waste discharge levels are always adhered to during daily internal controls, and even during official monitoring exercises, no overruns have been noted.
Further benefits: - Clear water phase without residual turbidity
- Significantly improved sludge conditioning
At a joint annual meeting at the end of December 2018, the customer and F&S were able to draw a wholly positive balance.
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