Ozone/biofiltration for removing MIB and geosmin

A serious and increasingly frequent problem that water utilities face is the occurrence of tastes and odors in drinking water. One of the most common and problematic types of tastes and odors is the musty/earthy type caused by 2-methylisoborneol (MIB) and trans-1,10-dimethyl-trans-9-decalol (geosmin). Common taste and odor treatment methods such as powdered activated carbon, chlorine oxidation, and potassium permanganate oxidation are largely ineffective for reducing these compounds. Fortunately, ozonation followed by biofiltration can provide a well-suited and effective treatment combination. Ozonation provides at least partial removal of MIB and geosmin, but it also creates undesirable biological instability. Subsequent biofiltration can remove residual MIB and geosmin while at the same time removing the biological instability. A preliminary investigation at a full-scale treatment plant indicates that the ozonation/biofiltration tandem can effectively reduce MIB to below threshold concentrations and that biofiltration plays an important role in this reduction.