Treatment of diglyme containing wastewater by advanced oxidation - processdesign and optimisation

Diglyme (CAS No. 111-96-6), a biorefractive ether with teratogenic properti es is of considerable importance as a solvent in the synthetic chemical ind ustry. Results of lab-scale investigations into the optimal conditions for the oxidative mineralisation of 0.05 to I g/L of diglyme in synthetic proce ss waters by hydrogen peroxide and ozone based advanced oxidation processes are presented. Fenton, photo-assisted Fenton and UV/H2O2 oxidation process es show acceptable TOO removals. At 50 degreesC the initial TOO removal rat es varies between 0.07 and 6g TOC/L*h. The rates increase with the initial diglyme and hydrogen peroxide concentration as well as with the UV irradiat ion energy intensity. For example at a 1 g/l diglyme concentration a stoich iometric H2O2 addition resulted in TOO degradation of 60% to 70% after 30 m inutes under the investigated conditions. Treatment with ozone/H2O2 at a pH of 8 and 25 degreesC required at least 100 minutes to achieve comparable m ineralisation results. Biodegradability can be reached in far shorter times . Ozone on its own cannot be recommended for diglyme treatment. If complete mineralisation of diglyme is the objective, the UV/H2O2 oxidation process should be favoured. The ozone/H2O2 process might offer a viable alternative in cases where the oxidation step is followed by biological wastewater tre atment, so that biodegradability is aimed at.