19 August 2021
New treatment plant at a Belgian coating company
Late last year, a Belgian coating company asked Chemtrade International to propose a replacement for its existing plant, which needed modernisation to meet current requirements. Together with the customer, we developed a solution reusing some existing components. The plant has now been installed and commissioned.
Wastewater source
The company specialises in cathodic electrodeposition coating (KTL) and powder coating on aluminium, steel, stainless steel and galvanised steel. Rinsing baths remove residues from pickling and degreasing baths, generating wastewater containing heavy metals. It cannot be discharged untreated to surface water or sewers.
Approach
As usual, sampling, analysis and treatment trials were the first step. They produced a treatment proposal meeting local emission limits.
Chemtrade International and EFA Chemie GmbH surveyed the site. Much of the plant needed replacement, but several buffers and the chamber filter press remained usable after modification. Retained components were updated with modern equipment and instrumentation.
Customer requirements were agreed to provide a system with a long service life.
Plant technology
The proposal included a new reactor, sludge buffer and chemical dosing stations.
Physicochemical treatment first adjusts pH to precipitate metals such as nickel, cobalt and silver for flocculation. EFAMULS then corrects pH and helps separate further solids to reach permitted emission levels. A polymer optimises the resulting flocs.
After a settling period in the reactor, sludge settles beneath a clear water layer. This water is pumped off without passing through the filter press, saving time. It still passes through filter baskets to capture suspended particles.
An additional pH check ensures discharge remains within the prescribed range. Remaining sludge is then pumped to the sludge tank.
The reactor is immediately ready for a new batch while sludge is pumped through the press. Several batches can therefore be treated each day in a compact plant.
A clear touchscreen visualisation shows the plant, with menus to view and adjust all controls.
Click an image to enlarge
