More than 1000 documents have been archived and studied by the research consortium, along with an extensive practical investigation of potentially applicable abiotic degradation techniques using ozone, radiolysis, or powerful radicals.
Technologies for 'radical degradation', using strong oxidising or reducing transient radicals, generated from hydrogen peroxide using thermal or photo-activation, have been worked out and optimised. Extensive dynamic modelling and simulation provides insight in the overwhelming complexity of initiation, termination and propagation of radical processes, the influence of control parameters on the extent of reaction, activation of H2O2 and O3, regeneration of catalyst, and dynamics of initial degradation of dyes and acids.
Surprisingly, different pathways and efficiencies are obtained by selected activation technologies, e.g. O3, UV/H2O2, Fe/H2O2, UV/Fe/H2O2 and well defined conditions of pH, temperature and oxygen concentration. Complete transfer of xenobiotic dyebath constituents into carbon-dioxide and water is possible. However, partial destruction of many dyes and auxiliaries makes dyebath effluents less toxic and more amendable for bioelimination.
Practical catalysts were identified as well as efficient energy sources, reactor configurations, control conditions and parameters. The influence of many dyebath constituents on the efficiency of ExCOLOUR technologies has been identified.
Careful attention to the chemistry of dye-bath formulations and dyeing processes not only allowed to overcome astonishing differences between individual dyes and real effluents in speed and extent of degradation, but also allows to find opportunities to reduce cost of treatment by exploiting chemicals, equipment and technologies already available.
New concepts and process of integrated abiotic and biotic treatment technologies allow 'Extensive Colour Removal' and provide solutions for recovery and recycling.
The aim of the project is to develop and optimise an innovative method for treating waste waters.
Advanced oxidation processes (AOP) are presented as the prime technologies to detoxify and destroy colour and persistent chemicals, to release metals from metal-complex dyes and to enhance bio-degradation before going into a biological treatment phase.
ExCOLOUR will use advanced oxidation proceses (AOP) and more particular catalysed peroxidation. AOP are defined as treatment processes which generate significant concentrations of hydroxyl-radicals (OH ), the most powerful and clean oxidant in nature.
To reach these objectives first of all a representative test set will be defined, taking into consideration the chemical and ecological composition of the samples. Laboratory tests will be performed with different AOP technologies. In a first stage tests will be performed on model compounds, later on synthetic and real effluents (mixid and from specific treatments) will be tested.
A mathematical model incorporating the chemical and technical characteristics of treatment will be constructed.
On-site tests will be performed by different textile companies in idfferent member states.
Finally the possibilities for water recycling will be evaluated.
Funding SchemeCSC - Cost-sharing contracts