Biotic and abiotic degradation behaviour of ethylene glycol monomethyl ether (EGME)

Glycol ethers are widely used in many processes in the chemical industry. Their high water solubility means they are used as solvents for different purposes (e.g. lacquers and varnishes). Since glycol ethers are known to produce toxic metabolites such as the teratogenic methoxyacetic acid during biodegradation, the biological treatment of glycol ethers can be hazardous. However, using oxidizing agents like hydrogen peroxide could be a feasible option for treating wastewater containing glycol ether. In this study, both-, biodegradation and abiotic oxidation experiments with ethylene glycol monomethyl ether (EGME) as contaminant were performed. The biodegradation experiments were conducted with a synthetic model wastewater containing 15 wt% NaCl and 5000 mgl(-1) of EGME. While experiments with the fungus Aspergillus versicolor resulted in the exhaustive biotic degradation of EGME, the toxic metabolite methoxyacetic acid (MAA) was produced as a 'dead end' product. Sodium hydroxide was added to adjust the decreasing pH caused by the production of MAA. In abiotic degradation experiments with EGME, other degradation products--organic acids and toxic aldehydes, e.g. methoxy acetaldehyde (MALD)--were detected. It must be taken into account that EGME and its biotic and abiotic degradation products are usually not analysed in routine wastewater measurements owing to their physical properties.