Coloring of alumina is a standard process in anodizing. Applications are tending towards increasingly vibrant and colorful shades, especially in facade engineering.
Environmentally speaking, these dyes are a problem, because increasingly stable and resistant structures and formulas are being developed.
In this case, the enviolet UV oxidation offers the perfect solution. The chromophoric structures are destroyed quickly and with a low energy demand and the dyes are eliminated from rinsing water and/or waste water.
Nearly all cases offer the possibility to recover the leached water for the rinsing process. Thus, the profitability of the production process will be improved significantly.
Waste water from crack-detection testing does not only contain strong dyes which can be detected even in traces, but also test oils based on hydrocarbons. Therefore, these waste waters need to be treated. According to recent law, these oils have to be bioavailable, and this leads to big problems with standard technologies like activated carbon or membrane filtration by biofouling. Our process does not only eliminate the dyes, but also destroys the COD, hence leaving a simple waste water, free of contaminations such as hydrocarbons.