The St. Paul Regional Water Services (SPRWS) has an annual problem with taste and odor complaints that arise in the summer. The taste and odor complaints were linked to the presence of geosmin (trans-1,10-dimethyl-trans-9-decalol) in the water, which is produced by algae growing in the chain of lakes supplying the treatment plant. The goal of this research was to evaluate treatment options for removing geosmin from the water. Pilot-scale experiments were performed to evaluate geosmin removal by three parallel treatment trains: anthracite-sand filter (control), GAC filter-adsorber, and ozone followed by a GAC filter-adsorber. Batch experiments were also performed to investigate geosmin sorption behavior, geosmin biodegradation, and geosmin degradation by ozone. The main findings of this work include: (1) GAC is an effective treatment option even with a relatively high background total organic carbon concentration, (2) ozone significantly improves geosmin removal and extends GAC bed life, (3) biodegradation can be a significant loss mechanism for geosmin in rapid filters, and (4) recommendations on how to perform GAC studies to get accurate predictions of full-scale performance. Two journal articles on this work are in preparation.
