Pilot Scale Studies of Geosmin and 2-Methylisoborneol Removal

Water blooms of O.bornettii, a producer of off-flavour compounds, occasionally occur in Lake Mjoesa. Accordingly a new water works is planned to alleviate the associated taste and odour problems. A pilot plant was constructed in 1985 and a continuous water treatment study was performed over a one year period. Granular activated carbon (GAC) was compared with ozonation-GAC. Filtrasorb-400 was used and the empty-bed contact-time of the GAC-filters was 21 min. The ozone dosage varied from 2 to 5 mg O₃/l. To simulate water blooms, commercially produced geosmin and 2-methyliso-borneol (MIB) were added to the water in concentrations from 10 to 190 ng/l. A slightly higher TOC-uptake was seen in the ozonation-GAC combination. This may indicate that the ozonation process is forming organic oxidation products that are competing with the geosmin and MIB for adsorption sites in the GAC-filter.