ELIMINATION OF TERPENOID ODOROUS COMPOUNDS BY SLOW SAND AND RIVER BANK FILTRATION OF THE RUHR RIVER, GERMANY

The elimination of odorous compounds by river bank and slow sand filtration was studied at the Ruhr River in Germany. The aquifer of the river bank filtration was anoxic and exhibited intense dissimilatory nitrate reduction; the aquifer of the slow sand filter was oxic. Polar monoterpenes, such as linalool, menthol, isobonlyl acetate, lipoxygenase products (oct-1-en-3-ol) and geosmin exhibited a much higher percentage elimination than monoterpene hydrocarbons and other lipophilic compounds (dimethyldisulphide, aliphatic and aromatic hydrocarbons). The efficiency of river bank filtration was slightly better than that of slow sand filtration. The schmutzdecke and upper layers of the slow sand filters were responsible for most of the removal of VOC. The deeper layers exhibited only small effects.