MTBE has come into focus of water suppliers since raw water sources had to be closed down in Santa Monica, California, at the beginning of the 1990s. Since then many studies have been undertaken to investigate the removal of MTBE from water. Other ethers which are under discussion as substitutes for MTBE have lately been developed and have to be assessed for their relevance for drinking water production. The present study shows that ethers used as oxygenates in fuel are not easily eliminated by advanced treatment technologies. Neither pure ozonation nor UV irradiation results in a significant concentration decline. The formation of highly reactive OH radicals is necessary to yield a decisive removal of the ethers from water. The application of combined UV/H2O2 or UV/ozone showed in all cases good results. The findings of the lab-scale experiments are verified by measurements in waterworks which have trace concentrations of MTBE in their raw water. Though the elimination process is better with the ethers under discussion as substitutes for MTBE, the removal efficiency is still very low compared to many other substances. A small improvement could be achieved by the substitution but in the end no real progress is made. Therefore, from the point of view of water suppliers the use of other ethers as a substitute for MTBE is posing the same problems as with MTBE.
- drinking water treatment
- © IWA Publishing 2007