Das Projekt "Entwicklung eines Verfahrens zur Wiederverwendung des bei fotografischen Prozessen verwendeten Spuelwassers sowie zur Wiederverwendung oder zum Abbau der entfernten Schadstoffe" wird vom Umweltbundesamt gefördert und von Universität Erlangen-Nürnberg, Institut für Physikalische und Theoretische Chemie, Lehrstuhl für Physikalische Chemie I durchgeführt. The most important substances to be removed are the developing compounds (p-phenylenediamines, p-aminophenols, hydroquinone, phenidones) and their products of oxidation, deamination, hydroxylation and sulfonation, as well as the fixing compounds (in particular thiosulphate and its silver complexes), and the bleaching compounds (certain iron(III)-complexes), as well as complexing agents (EDTA, PDTA, ADA) and compounds like bromide. The harmful compounds will be removed from the wash water of both the development and the fixing process by adsorption at suitable adsorbents. The loaded adsorbents will be substituted by unloaded ones and recycled at a central station. Some of the desorbed compounds will be recovered, the other ones will completely controlled be destroyed by a combined chemical and electrochemical method. This method shall also be used to convert the components of the overflow of photographic baths into biodegradable substances. The procedure for the re-use of the wash water may be applied by all kind of minilabs, in particular by hospitals and medical practices. It may also be used, however, by all companies that use graphic film material. The collection and recycling of the loaded adsorbents may be carried out by those companies which already deal with the waste management of used developing and fixing baths.
Das Projekt "Oxidative stress during degradation of phenolic compounds by bacterial ipso-hydoxylases - a challenge for the cell" wird vom Umweltbundesamt gefördert und von Eawag - Das Wasserforschungsinstitut des ETH-Bereichs durchgeführt. Preliminary results of transformation experiments with technical nonylphenol indicate that besides hydroquinone various alkylhydroquinones are produced as side products by ipso-hydroxylation. Because hydroquinones and alkylhydroquinones are agents of oxidative stress and have a high toxic potential, we plan to investigate the molecular processes associated with their formation and their further fate. In a metabolomics approach based on identification and quantification of putative metabolites by GC/MS and GC x GC/ToFMS, we intend to unravel the unique alkylhydroquinone fingerprint produced by ipso-degradation of technical nonylphenol in strain Bayram. There are indications that two reducing enzymes, a benzoquinone reductase that can quickly convert p-quinone into hydroquinone and a ferredoxin, able to reactivate TTNP3's hydroquinone-1,2-dioxygenase are involved in cell protection. We plan to elucidate the exact role of these enzymes in the metabolism of nonylphenols. The expected results will help us to shed new light on the metabolic strategies that microorganisms able to degrade potentially toxic phenolic substrates have evolved to cope with such substrates and their metabolites. This will be a major advance in the understanding of cellular responses to oxidative stress immanent to biodegradation of phenolic compounds.