TY - JOUR
T1 - Occurrence and removal of earthy-musty odorants in two waterworks in Kinmen Island, Taiwan
AU - Hsieh, Wen Hsing
AU - Chang, De Wei
AU - Lin, Tsair Fuh
N1 - Publisher Copyright:
© 2014 American Society of Civil Engineers.
PY - 2015/7/1
Y1 - 2015/7/1
N2 - 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.
AB - 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.
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U2 - 10.1061/(ASCE)HZ.2153-5515.0000209
DO - 10.1061/(ASCE)HZ.2153-5515.0000209
M3 - Article
AN - SCOPUS:84936943080
SN - 2153-5493
VL - 18
JO - Journal of Hazardous, Toxic, and Radioactive Waste
JF - Journal of Hazardous, Toxic, and Radioactive Waste
IS - 3
M1 - 04014012
ER -