The Relationship between Concentration and Sensory Properties of 2-Methylisoborneol and Geosmin in Drinking Water

The study of the relations between the senses of smell and taste and odorant concentration is important for the solution of odor problems. The threshold concentrations of odor and taste (TOC, TTC) of 2-methylisoborneol (MIB) and geosmin were measured by the non-forced choice triangle method using 12-20 panelists. Both TOC and TTC were found to be functions of water temperature and the concentration of residual chlorine. The TOC and TTC of mixed samples were rather lower than the concentrations calculated from the mixing ratio. The sensitivities of the consumer panel and the number of musty odor complaints from consumers are related to MIB or geosmin concentration. The ratio of the number of complaints to MIB (or geosmin) concentration decreased after maximum complaint, but the sensitivity of the consumer panel remained the same.

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PTSA (pressure and thermal swing adsorption) method to remove trihalomethanes from drinking water

Water Science & Technology ◽

10.2166/wst.1997.0283 ◽

1997 ◽

Vol 35 (7) ◽

pp. 243-250 ◽

Cited By ~ 1

Author(s):

Shigekazu Nakano ◽

Tomoko Fukuhara ◽

Masami Hiasa

Keyword(s):

Drinking Water ◽

Residual Chlorine ◽

Remarkable Difference ◽

Adsorption Method ◽

Heating And Cooling ◽

Point Of Use ◽

Thermal Swing Adsorption ◽

Long Time ◽

Musty Odor ◽

Vacuum Heating

It has been widely recognized that trihalomethanes (THMs) in drinking water pose a risk to human health. THMs can be removed to a certain extent by the conventional point-of-use (POU) unit which is composed of activated carbon (AC) and microfilter. But it's life on THMs is relatively shorter than on residual chlorine or musty odor. To extent the life of AC adsorber, pressure and thermal swing adsorption (PTSA) was applied by preferential regeneration of chloroform. PTSA was effective to remove THMs, especially chloroform. Adsorption isotherms of chloroform at 25 and 70°C showed a remarkable difference so that thermal swing was considered effective. Chloroform was also desorbed by reducing pressure. By vacuum heating at 70°C, chloroform was almost desorbed from AC and reversible adsorption was considered possible. A prototype of POU unit with PTSA was proposed. Regeneration mode would consist of dewatering, vacuum heating and cooling (backwashing). The unit was maintained in bacteriostatic condition and could be used for a long time without changing an AC cartridge.

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Trihalomethanes formation in Iranian water supply systems: predicting and modeling

Journal of Water and Health ◽

10.2166/wh.2015.211 ◽

2015 ◽

Vol 13 (3) ◽

pp. 859-869 ◽

Cited By ~ 5

Author(s):

Ali Akbar Babaei ◽

Leila Atari ◽

Mehdi Ahmadi ◽

Kambiz Ahmadiangali ◽

Mirzaman Zamanzadeh ◽

...

Keyword(s):

Drinking Water ◽

Water Temperature ◽

Distribution Systems ◽

Water Distribution ◽

Pearson Correlation ◽

Multiple Linear Regression Model ◽

Residual Chlorine ◽

Water Supply Systems ◽

Drinking Water Distribution Systems ◽

Bromide Ion

Trihalomethanes (THMs) were the first disinfection by-products discovered in drinking water and are classified as probable carcinogens. This study measures and models THMs formation at two drinking water distribution systems (WDS1 and WDS2) in Ahvaz City, Iran. The investigation was based on field-scale investigations and an intensive 36-week sampling program, from January to September 2011. The results showed total THM concentrations in the range 17.4–174.8 μg/L and 18.9–99.5 μg/L in WDS1 and WDS2, respectively. Except in a few cases, the THM concentrations in WDS1 and WDS2 were lower than the maximum contaminant level values. Using two-tailed Pearson correlation test, the water temperature, dissolved organic carbon, UV254, bromide ion (Br−), free residual chlorine, and chlorine dose were identified as the significant parameters for THMs formation in WDS2. Water temperature was the only significant parameter for THMs formation in WDS1. Based on the correlation results, a predictive model for THMs formation was developed using a multiple regression approach. A multiple linear regression model showed the best fit according to the coefficients of determination (R2) obtained for WDS1 (R2 = 0.47) and WDS2 (R2 = 0.54). Further correlation studies and analysis focusing on THMs formation are necessary to assess THMs concentration using the predictive models.

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Effect of Rainfall and pH on Musty Odor Produced in the Sanbe Reservoir

Water ◽

10.3390/w13243600 ◽

2021 ◽

Vol 13 (24) ◽

pp. 3600

Author(s):

Sangyeob Kim ◽

Shohei Hayashi ◽

Shingo Masuki ◽

Kazuhiro Ayukawa ◽

Shuji Ohtani ◽

...

Keyword(s):

Drinking Water ◽

Water Temperature ◽

Inorganic Carbon ◽

Dissolved Inorganic Carbon ◽

Water Systems ◽

Cyanobacterial Blooms ◽

Field Observations ◽

The World ◽

Musty Odor ◽

Harmful Cyanobacterial Blooms

Harmful cyanobacterial blooms are continuously formed in water systems such as reservoirs and lakes around the world. Geosmin and 2-methylisoborneol (2-MIB) produced by some species of cyanobacteria have caused odor problems in the drinking water of the Sanbe Reservoir in Japan. Field observations were conducted for four years (2015–2019) to investigate the cause of this musty odor. It was found that geosmin was produced by Dolichospermum crassum and Dolichospermum planctonicum (cyanobacteria), and 2-MIB was due to Pseudanabaena sp. and Aphanizomenon cf. flos-aquae (cyanobacteria). Changes in water temperature and pH caused by rainfall were correlated with changes in the concentration of geosmin and 2-MIB. In particular, geosmin and 2-MIB tended to occur under low rainfall conditions. When there was low rainfall, the reservoir changed to an alkaline state because the phytoplankton consumed CO2 for photosynthesis. In an alkaline reservoir, dissolved inorganic carbon mainly existed in the form of bicarbonate (HCO3−). Thus, the results suggest that under such conditions in reservoirs, cyanobacteria grew easily because they could use both CO2 and HCO3− for photosynthesis. Specifically, our study suggests that in order for the musty odor problem in the reservoir to be solved, it is important that the pH of the reservoir be controlled.

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The Detection of Taste and Odor in Osaka's Drinking Water

Water Science & Technology ◽

10.2166/wst.1988.0222 ◽

1988 ◽

Vol 20 (8-9) ◽

pp. 37-42 ◽

Cited By ~ 3

Author(s):

H. Sano

Keyword(s):

Drinking Water ◽

Tap Water ◽

Odor Concentration ◽

Consumer Panel ◽

Taste And Odor ◽

Musty Odor ◽

Taste Assessment

Laboratory and consumer panels were used to determine the threshold odor concentration(TOO of 2-methylisoborneol (MIB) and geosmin in water. The consumer panel was also used to assess the taste of tap water. The results showed that laboratory panel TOCs of MIB and geosmin were 4 and 94 ng/l respectively, while those of consumer panels were 12 and 360 ng/l respectively. In taste assessment, 8% of consumers assessed drinking water as offensive or bad even when the tap water wasn't contaminated by musty odor substances. However if it was contaminated by MIB at its TOC level, 17% of consumers assessed the water as offensive and bad.

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Behavior of Musty Odorous Compounds during the Process of Water Treatment

Water Science & Technology ◽

10.2166/wst.1988.0251 ◽

1988 ◽

Vol 20 (8-9) ◽

pp. 261-267 ◽

Cited By ~ 20

Author(s):

K. Ashitani ◽

Y. Hishida ◽

K. Fujiwara

Keyword(s):

Drinking Water ◽

Water Treatment ◽

Pilot Plant ◽

Residual Chlorine ◽

Raw Water ◽

Undetectable Level ◽

Sand Filter ◽

Musty Odor ◽

Free Residual Chlorine ◽

Suspended Form

Geosmin and 2-methylisoborneol (MIB) are two of the causative compounds responsible for the musty odor problem in drinking water. Geosmin and MIB in raw water were present both in solution and in a suspended form mostly associated with the host cyanobacteria. Geosmin and MIB in suspended form were well removed by coagulation and sedimentation alone. Geosmin present in solution could be removed almost to an undetectable level in the rapid sand filter of the pilot plant where no pre-chlorination was practiced. Breakpoint pre-chlorination, however, forced geosmin and MIB present inside of the host algae to leak into the water. The concentration of MIB decreased in a sedimentation basin during the daytime, but not at night in the plant practicing breakpoint pre-chlorination. Geosmin and MIB were both decomposed under sunlight in the presence of free residual chlorine.

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Removal of Musty Odor Compound in Drinking Water by Biological Filter

Water Science & Technology ◽

10.2166/wst.1992.0066 ◽

1992 ◽

Vol 25 (2) ◽

pp. 307-314 ◽

Cited By ~ 20

Author(s):

K. Egashira ◽

K. Ito ◽

Y. Yoshiy

Keyword(s):

Drinking Water ◽

Water Temperature ◽

Granular Media ◽

Packed Column ◽

Oxygen Demand ◽

Biological Filtration ◽

Biological Filter ◽

Drinking Water Resources ◽

Musty Odor ◽

Musty Odor Compound

In order to remove the musty odor compound 2-methyl isoborneol (MIB) from drinking water resources at Lake Biwa, a pilot plant of a biological filtration was installed and operated. In this study, the effects of water temperature, pH and initial concentration of MIB on the MIB degradation potential of the ceramic media packed column in the biological filter were studied. Microorganisms on the surface of the granular media were observed under the scanning electron microscope (SEM). Bacteria which were responsible for the degradation were isolated, studied and identified. From this experiment, the extent of the effect of water temperature on the degradation potential was found to be similar to that on the biochemical oxygen demand (BOD) removal activity by an activated sludge. The optimum pH for the degradation potential was seen to be between 7 and 9. The MIB degradation reaction was seen to be almost a first order reaction. On the surface of the washed granular media, coccoid and rod-shaped bacteria were observed. Eleven out of 34 bacteria isolated from the washed media were judged as biodegraders. Some characteristics of 7 Gram negative biodegraders were studied and two strains of Pseudomonasaeruginosa,one strain of Flavobacteriummultivorum, one strain of Pseudomonas sp. and one strain of Flavobacterium sp. were identified.

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A Residual Chlorine Removal Method to Allow Drinking Water Monitoring by Biological Early Warning Systems

10.21236/ada432455 ◽

2005 ◽

Cited By ~ 2

Author(s):

Willian H. VAN DER Schalie ◽

David E. Trader ◽

Mark W. Widder ◽

Tommy R. Shedd ◽

Linda M. Brennan

Keyword(s):

Drinking Water ◽

Early Warning ◽

Early Warning Systems ◽

Water Monitoring ◽

Residual Chlorine ◽

Warning Systems ◽

Removal Method ◽

Chlorine Removal

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The relationship between musty-odor-causing organisms and water quality in Lake Biwa

Water Science & Technology ◽

10.2166/wst.1995.0426 ◽

1995 ◽

Vol 31 (11) ◽

pp. 153-158 ◽

Cited By ~ 3

Author(s):

M. Kajino ◽

K. Sakamoto

Keyword(s):

Water Quality ◽

Data Analysis ◽

Green Algae ◽

Analytical Methods ◽

Lake Biwa ◽

Blue Green Algae ◽

Odor Compounds ◽

Musty Odor ◽

The Relationship

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.

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