A systematic study on the odorants characterization and evaluation in a plain reservoir with wetlands ecosystem.

The odor problems in plain reservoirs are more complex compared to valley reservoirs and ground water reservoirs. Just as YL Reservoir with wetlands ecosystem in Lixiahe Plain, Jiangsu Province has been suffering from complex odors, however, the odorants were unclear. In this study, a systematic study on odorants characterization and evaluation of plain YL reservoir was accomplished. Totally musty, septic, fishy, chemical and grassy odors were first identified simultaneously, twenty-four odorants were identified correspondingly. According to odor activity value ranking, 2-methylisoborneol and geosmin, with odor activity values of 14-18 and 2.5-3.8, were major musty odorants, while bis(2-chloroisopropyl) ether, dimethyl disulfide, dimethyl trisulfide, pentanethiol and indole, with odor activity values of 15.3-18.8, 1-1.3, 1.5-2.3, 2-3 and 0.7-0.9, were major septic compounds. Fishy and grassy odors were associated with 2,4-decadienal, hexanal, nonanal, decanal, benzaldehyde and β-cyclocitral, while chemical odor was related to indane, eucalyptol, 2-nitrophenol, 2-methylphenol, tetramethylpyrazine, 1,4-dichlorobenzene, p-xylene and ethylbenzene. By reconstituting tests, 98, 95, 88, 85 and 81 % of musty, septic, fishy, chemical and grassy characteristics in source water could be explained. It was notable that wetlands ecosystem has almost no effect on odor removal. This study would offer more understandings and supports for odors's control in such source waters.