Abstract
In this study, the occurrence and treatment of two earthy-musty odorants, geosmin and 2-MIB, produced by cyanobacteria is investigated at two conventional drinking-water treatment plants (WTPs) at Kinmen Island, Taiwan. Samples of the source, processed, and finished waters and tap water at the two WTPs were collected and analyzed. Both geosmin and 2-MIB were commonly detected in most water samples, with the 2-MIB concentration much higher than the geosmin concentration. About 78% of the source water samples and 35% of the finished and tap water samples showed detected 2-MIB levels higher than the odor threshold concentration (OTC, ~10 ng/L). Sampling and analysis of the reservoir water indicated that 2-MIB is uniformly distributed in the reservoir, with ~70% of which existing in the dissolved phase. The chlorination study of the raw water indicates that both geosmin and 2-MIB are resistant to chlorine. However, the cyanobacterial cells in raw water were effectively ruptured within15 min of the contact time when a chlorine dosage of 6.4 mg/L was applied at the WTPs. A monitoring of the processed water at WTPs shows that the flotation process is most effective to the removal of cyanobacteria, with about 77-79% efficiency, compared to ~99.4% achieved with the whole treatment train. Removal of 2-MIB by the treatment processes before flotation was only about 17-28%, which may be limited to the low ratio of cell-bound 2-MIB. The two sand filtration processes removed 23-47% of 2-MIB, due probably to the biological degradation of dissolved 2-MIB. For the two WTP studied, the removal of 2-MIB was about 74%. It is shown that 2-MIB is a major odorant in the drinking water source and the finished water at Kinmen Island. The current processes are not sufficient to remove 2-MIB to a level below the OTC. Advanced processes are needed to effectively remove the odorant.
Original language | English |
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Article number | 04014012 |
Journal | Journal of Hazardous, Toxic, and Radioactive Waste |
Volume | 18 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2015 Jul 1 |
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Chemical Engineering(all)
- Water Science and Technology
- Geotechnical Engineering and Engineering Geology
- Waste Management and Disposal