Taste and odor （T＆O） problems in drinking water frequently occur because of many compounds present in the water, of which trans-1,10-dimethyl-trans-9-decalol （geosrnin） and 2-methylisoborneol （MIB） are well-kno...Taste and odor （T＆O） problems in drinking water frequently occur because of many compounds present in the water, of which trans-1,10-dimethyl-trans-9-decalol （geosrnin） and 2-methylisoborneol （MIB） are well-known. In this study, a fast and effective method was established for simultaneous determination of 10 T＆O compounds, including geosmin, MIB, 2,4,6-trichloroanisole （TCA）, 2-methylbenzofuran, 2-isopropyl-3-methoxypyrazine （IPMP）, 2-isobutyl-3-methoxypyrazine （IBMP）, cis-3-hexenyl acetate, trans,trans-2,4-heptadienal, trans, cis-2,6-nonadienal, and trans-2-decenal in water samples by headspace solid-phase microextraction （SPME） coupled with gas chromatography-mass spectrometry. An orthogonal array experimental design was used to optimize the effects of SPME fiber, extraction temperature, stirring rate, NaC1 content, extraction time, and desorption time. The limits of detection ranged from 0.1 to 73 ng/L were lower than or close to the odor threshold concentrations （OTCs）. All the 10 T＆O compounds were detected in the 14 water samples including surface water, treatment process water and tap water, taken from a waterworks in Lianyungang City, China. MIB and geosmin were detected in most samples at low concentration. Six T＆O compounds （IPMP, IBMP, trans,cis-2,6-nonadienal, 2-methylbenzofuran, trans-2-decenal, and TCA） were effectively decreased in water treatment process （sedimentation and filtration） that is different from cis-3-hexenyl acetate, MIB and geosmin. It is noted that the TCA concentrations at 15.9-122.3 ng/L and the trans,cis-2,6-nonadienal concentrations at 79.9-190.1 ng/L were over 10 times higher than their OTCs in tap water. The variation of the analytes in the all water samples, especially distribution system indicated that distribution system cannot be ignored as a T＆O compounds source.展开更多
In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O com...In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.展开更多
In this paper, a method using solid-phase extraction （SPE） and gas chromatography-mass spectro- metry （GC-MS） was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2- methyl...In this paper, a method using solid-phase extraction （SPE） and gas chromatography-mass spectro- metry （GC-MS） was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2- methylisoborneol （2-MIB）, 2,4,6-trichloroanisole （TCA）, 2-isopropyl-3-methoxy pyrazine （IPMP）, 2-isobutyl-3- methoxy pyrazine （IBMP）, and trans-l,lO-dimethyl- trans-9-decalol （geosmin, GSM）. The mass spectrometry was operated in selective ion monitoring （SIM） mode. Three kinds of SPE columns and three eluting solvents were compared, the C 18 column was chosen as optimum SPE column, and methanol was chosen as the optimum eluting solvent. It was found that the method showed good linearity in the range of 1-200 ng.L^-1 and gave detection limits of 0.5 1.5 ng.L^-1 for individual compounds. Good recoveries （93.5%-108%） and relative standard deviations （1.58%-7.31%） were also obtained. Additionally, concentrations of these taste and odor compounds in Jinan＇s surface and drinking water were analyzed by applying this method, and the results showed that GSM and 2-MIB were the dominant taste and odor compounds in Jinan＇s raw water.展开更多
A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavo...A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.展开更多
Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble ca...Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble carbohydrates additions to swine manure on odorous compounds, chemical compounds and indigenous flora were evaluated. Additions were calculated on dried manure weight basis. Variables monitored included ammonia （NH3）, hydrogen sulfide （H2S）, odor offensiveness, pH, ammonium nitrogen（NH4^＋-N）, volatile fatty acids （VFAs）, urease and indigenous flora. The results indicated that the combination of L. plantarum and soluble carbohydrates dramatically reduced manure pH. Lower pH resulted in the reduction of NH3 volatilization （34.6%-92.4%, P〈0.01）, the increases of H2S （P〈 0.05） and NH4^＋-N （5.3%-17.5%, P〈0.05）. In addition, L. plantarum and soluble carbohydrates additions significantly reduced odor offensiveness, those VFAs related to malodor indicators（valeric acids, 12.3%-47.7%, P〈 0.05; iso-valeric, 3.5%-23.8%） and the main microorganisms responsible for odor production, with the number of Eubacteria in swine manure reducing by 4.9%, 11.6%, 17.4%, 34.1% and 32.2% respectively.展开更多
A wide range of compounds with various structural features can cause taste and odor(T&O)problems in drinking water. It would be desirable to determine all of these compounds using a simple analytical method. In th...A wide range of compounds with various structural features can cause taste and odor(T&O)problems in drinking water. It would be desirable to determine all of these compounds using a simple analytical method. In this paper, a sensitive method combining liquid–liquid extraction(LLE) with gas chromatography-triple quadrupole tandem mass spectrometry(GC–MS/MS)was established to simultaneously analyze 51 odor-causing compounds in drinking water,including organic sulfides, aldehydes, benzenes, phenols, ethers, esters, ketones, nitrogenous heterocyclic compounds, 2-methylisoborneol and geosmin. Three deuterated analogs of target analytes, dimethyl disulfide-d6, benzaldehyde-d6 and o-cresol-3,4,5,6-d4,were used to correct the variations in recovery, and five isotope-labeled internal standards(4-chlorotoluene-d4, 1, 4-dichlorobenzene-d4, naphthalene-d8, acenaphthene-d10, phenanthrene-d10 respectively) were used prior to analysis to correct the variations arising from instrument fluctuations and injection errors. The calibration curves of the target compounds showed good linearity(R2> 0.99, level = 7),and method detection limits(MDLs) below 1/10 of the odor threshold concentrations were achieved for most of the odorants(0.10–20.55 ng/L). The average recoveries of most of the analytes in tap water samples were between 70% and 120%, and the method was reproducible(RSD < 20%, n = 7). Additionally, concentrations of odor-causing compounds in water samples collected from three drinking water treatment plants(DWTPs) were analyzed by this method.According to the results, dimethyl trisulfide, dimethyl disulfide and indole were considered to be the key odorants responsible for the swampy/septic odor. 2-Methylisoborneol and geosmin were detected as the main odor-causing compounds for musty/earthy odor in DWTP B.展开更多
In this study, the amounts of odorous carbonyl compounds （OCCs） including acetaldehyde （Acet-A）, propionaldehyde （Pron-A）, butylaldehyde （Buty-A）, iso-valeric aldehyde （Iso-Vale-A） and n-valeric aldehyde （N...In this study, the amounts of odorous carbonyl compounds （OCCs） including acetaldehyde （Acet-A）, propionaldehyde （Pron-A）, butylaldehyde （Buty-A）, iso-valeric aldehyde （Iso-Vale-A） and n-valeric aldehyde （N-Vale-A） emitted from a fishery industrial complex near the exhibition facilities of ＂Expo 2012 Yeosu Korea＂ were measured. Acet-A was found to be the most abundant OCC, and the total concentrations of the OCCs were the highest in the summer. However, due to vehicular exhaust and photochemical reactions, the concentrations of some of the OCCs presented their highest levels in the fall. A significant correlation between Acet-A and Buty-A was found at the major fishery facilities （r = 0.816, p = 1.87E-15, n = 60） and at the border areas （r = 0.809, p = 3.40E-12, n = 48） of this fishery industrial complex. The concentrations of OCCs at the border areas were not worse than those at the urban areas in other places, indicating that the concentrations of ambient OCCs at the border areas were not greatly influenced by manmade activities.展开更多
Source separation sanitation systems have attracted more and more attention recently.However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid ...Source separation sanitation systems have attracted more and more attention recently.However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid such issues, it is necessary to monitor the odor related compounds that might be generated during urine storage. This study investigated the odorous compounds that emitted from source-separated human urine under different hydrolysis conditions. Batch experiments were conducted to investigate the effect of temperature, stale/fresh urine ratio and urine dilution on odor emissions. It was found that ammonia, dimethyl disulfide, allyl methyl sulfide and 4-heptanone were the main odorous compounds generated from human urine, with headspace concentrations hundreds of times higher than their respective odor thresholds. Furthermore, the high temperature accelerated urine hydrolysis and liquid–gas mass transfer, resulting a remarkable increase of odor emissions from the urine solution. The addition of stale urine enhanced urine hydrolysis and expedited odor emissions. On the contrary, diluted urine emitted less odorous compounds ascribed to reduced concentrations of odorant precursors. In addition,this study quantified the odor emissions and revealed the constraints of urine source separation in real-world applications. To address the odor issue, several control strategies are recommended for odor mitigation or elimination from an engineering perspective.展开更多
The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water qualit...The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide （DMS）,dimethyl trisulfide （DMTS）,and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium （NH4＋-N） were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobacterial blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu.展开更多
The explosive increase of construction and demolition waste(CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were i...The explosive increase of construction and demolition waste(CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills(OIL), with organic matters/inert CDW components(O/I) from 5% to 30%, and the control group only with inert components(IL) or organics(OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content(ER_(total)), theory odor concentration(TOC_(total)), and e-nose concentration(ER_(ENC)), and their correlations with waste properties were also analyzed. It was found that the main contributors to ER_(total)(IL: 93.0% NH_(3);OIL: 41.6% sulfides, 31.0% NH_(3), 25.9% oxygenated compounds) and TOC_(total)(IL: 64.1% CH_3SH, 28.2% NH_(3);OIL: 71.7% CH_(3)SH, 24.8% H_(2)S) changed significantly. With the rise of O/I, ER_(total), TOC_(total), and ER_(ENC) increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10%(i.e., DOC < 101.3 mg/L). The good regressions between waste properties(DOC, DN, pH) and ER_(total),( r = 0.86, 0.86,-0.88, p < 0.05), TOC_(total),( r = 0.82, 0.79, -0.82, p < 0.05) implied that the carbon sources and acidic substances relating to organics degradation might result in that increase. Besides, the correlation analysis results( ER_(ENC) vs. TOC_(total,, r = 0.96, p < 0.01;vs. ER_(ENC), r = 0.86, p < 0.05) indicated that e-nose perhaps was a reliable odor continuous monitoring tool for CDW landfills.展开更多
基金supported by the National Natural Science Foundation of China(No.21007077,51290283)the Ministry of Water Resources’ Special Funds for Scientific Research on Public Causes(No.201201032)
文摘Taste and odor （T＆O） problems in drinking water frequently occur because of many compounds present in the water, of which trans-1,10-dimethyl-trans-9-decalol （geosrnin） and 2-methylisoborneol （MIB） are well-known. In this study, a fast and effective method was established for simultaneous determination of 10 T＆O compounds, including geosmin, MIB, 2,4,6-trichloroanisole （TCA）, 2-methylbenzofuran, 2-isopropyl-3-methoxypyrazine （IPMP）, 2-isobutyl-3-methoxypyrazine （IBMP）, cis-3-hexenyl acetate, trans,trans-2,4-heptadienal, trans, cis-2,6-nonadienal, and trans-2-decenal in water samples by headspace solid-phase microextraction （SPME） coupled with gas chromatography-mass spectrometry. An orthogonal array experimental design was used to optimize the effects of SPME fiber, extraction temperature, stirring rate, NaC1 content, extraction time, and desorption time. The limits of detection ranged from 0.1 to 73 ng/L were lower than or close to the odor threshold concentrations （OTCs）. All the 10 T＆O compounds were detected in the 14 water samples including surface water, treatment process water and tap water, taken from a waterworks in Lianyungang City, China. MIB and geosmin were detected in most samples at low concentration. Six T＆O compounds （IPMP, IBMP, trans,cis-2,6-nonadienal, 2-methylbenzofuran, trans-2-decenal, and TCA） were effectively decreased in water treatment process （sedimentation and filtration） that is different from cis-3-hexenyl acetate, MIB and geosmin. It is noted that the TCA concentrations at 15.9-122.3 ng/L and the trans,cis-2,6-nonadienal concentrations at 79.9-190.1 ng/L were over 10 times higher than their OTCs in tap water. The variation of the analytes in the all water samples, especially distribution system indicated that distribution system cannot be ignored as a T＆O compounds source.
基金supported by Shaanxi Provincial Key Research and Development Project(No.2022ZDLSF06-08)Shaanxi Provincial Key Scientific and Technological Innovation Team,China(No.2023-CX-TD-32)+1 种基金the Key Scientific Research Projects of Education Department of Shaanxi Province,China(No.22JY035)the Project of Youth Talent Lift Program of Shaanxi Association for Science and Technology,China(No.20230447).
文摘In the conventional water treatment process,algae have a propensity to breach the filter barriers and potentially seep into the water distribution system,leading to an elevation in taste and odor compounds(T&O compounds).This investigation delved into the seasonal fluctuations of algae penetration and the production of T&O compounds within the treatment units of Reservoir Water Plant 1(W1)and River Water Plant 2(W2).The findings indicated that despite the application of the‘pre-oxidation,coagulation and sedimentation(PCS),sand filtration,and disinfection’process,certain robust-walled filamentous Cyanobacteria,Bacillariophyta species,and small Chlorophyta genera managed to bypass the filters.The leakage of algal cells during autumn at W1 was particularly striking,with a peak of 1,170,000 cells/L.The concurrent assessment of the potential for T&O compound formation revealed an alarming high potential for 2-methylisoborneol(2-MIB)in the water leaving the plants,with concentrations soaring to 197.20 ng/L at W1 in autumn and 54.78 ng/L at W2 in summer.This underscores the significant capacity of residual algal cells to generate T&O compounds.Tracking the retention and penetration dynamics of algal cells across each drinking water treatment stage is crucial for surface water treatment facilities to develop effective operational and management strategies,thereby enhancing the safety and quality of drinking water for the end consumer.
文摘In this paper, a method using solid-phase extraction （SPE） and gas chromatography-mass spectro- metry （GC-MS） was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2- methylisoborneol （2-MIB）, 2,4,6-trichloroanisole （TCA）, 2-isopropyl-3-methoxy pyrazine （IPMP）, 2-isobutyl-3- methoxy pyrazine （IBMP）, and trans-l,lO-dimethyl- trans-9-decalol （geosmin, GSM）. The mass spectrometry was operated in selective ion monitoring （SIM） mode. Three kinds of SPE columns and three eluting solvents were compared, the C 18 column was chosen as optimum SPE column, and methanol was chosen as the optimum eluting solvent. It was found that the method showed good linearity in the range of 1-200 ng.L^-1 and gave detection limits of 0.5 1.5 ng.L^-1 for individual compounds. Good recoveries （93.5%-108%） and relative standard deviations （1.58%-7.31%） were also obtained. Additionally, concentrations of these taste and odor compounds in Jinan＇s surface and drinking water were analyzed by applying this method, and the results showed that GSM and 2-MIB were the dominant taste and odor compounds in Jinan＇s raw water.
文摘A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds, included geosmin, 2- methylisobomeol （MIB）, 2-isobutyl-3-methyoxypyrazine （IBMP）, and 2-isopropyl-3-methoxypyrazine （IPMP）. Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153 〉 121, 167 〉 125, 152 〉 95, and 165 〉 109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200ng·L^-1, and from 0.8 to 200ng·L^-1 for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.
文摘Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble carbohydrates additions to swine manure on odorous compounds, chemical compounds and indigenous flora were evaluated. Additions were calculated on dried manure weight basis. Variables monitored included ammonia （NH3）, hydrogen sulfide （H2S）, odor offensiveness, pH, ammonium nitrogen（NH4^＋-N）, volatile fatty acids （VFAs）, urease and indigenous flora. The results indicated that the combination of L. plantarum and soluble carbohydrates dramatically reduced manure pH. Lower pH resulted in the reduction of NH3 volatilization （34.6%-92.4%, P〈0.01）, the increases of H2S （P〈 0.05） and NH4^＋-N （5.3%-17.5%, P〈0.05）. In addition, L. plantarum and soluble carbohydrates additions significantly reduced odor offensiveness, those VFAs related to malodor indicators（valeric acids, 12.3%-47.7%, P〈 0.05; iso-valeric, 3.5%-23.8%） and the main microorganisms responsible for odor production, with the number of Eubacteria in swine manure reducing by 4.9%, 11.6%, 17.4%, 34.1% and 32.2% respectively.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(Nos.2015ZX07406001 and 2017ZX07207004)the National Natural Science Foundation of China(Nos.51778602 and 21707117)the Major Project of Key Laboratory of Drinking Water Science and Technology,Research Center for EcoEnvironmental Sciences,CAS(No.17Z02KLDWST)
文摘A wide range of compounds with various structural features can cause taste and odor(T&O)problems in drinking water. It would be desirable to determine all of these compounds using a simple analytical method. In this paper, a sensitive method combining liquid–liquid extraction(LLE) with gas chromatography-triple quadrupole tandem mass spectrometry(GC–MS/MS)was established to simultaneously analyze 51 odor-causing compounds in drinking water,including organic sulfides, aldehydes, benzenes, phenols, ethers, esters, ketones, nitrogenous heterocyclic compounds, 2-methylisoborneol and geosmin. Three deuterated analogs of target analytes, dimethyl disulfide-d6, benzaldehyde-d6 and o-cresol-3,4,5,6-d4,were used to correct the variations in recovery, and five isotope-labeled internal standards(4-chlorotoluene-d4, 1, 4-dichlorobenzene-d4, naphthalene-d8, acenaphthene-d10, phenanthrene-d10 respectively) were used prior to analysis to correct the variations arising from instrument fluctuations and injection errors. The calibration curves of the target compounds showed good linearity(R2> 0.99, level = 7),and method detection limits(MDLs) below 1/10 of the odor threshold concentrations were achieved for most of the odorants(0.10–20.55 ng/L). The average recoveries of most of the analytes in tap water samples were between 70% and 120%, and the method was reproducible(RSD < 20%, n = 7). Additionally, concentrations of odor-causing compounds in water samples collected from three drinking water treatment plants(DWTPs) were analyzed by this method.According to the results, dimethyl trisulfide, dimethyl disulfide and indole were considered to be the key odorants responsible for the swampy/septic odor. 2-Methylisoborneol and geosmin were detected as the main odor-causing compounds for musty/earthy odor in DWTP B.
基金support of this research program from the Jeonnam Green Environment Center (JNGEC),Korea
文摘In this study, the amounts of odorous carbonyl compounds （OCCs） including acetaldehyde （Acet-A）, propionaldehyde （Pron-A）, butylaldehyde （Buty-A）, iso-valeric aldehyde （Iso-Vale-A） and n-valeric aldehyde （N-Vale-A） emitted from a fishery industrial complex near the exhibition facilities of ＂Expo 2012 Yeosu Korea＂ were measured. Acet-A was found to be the most abundant OCC, and the total concentrations of the OCCs were the highest in the summer. However, due to vehicular exhaust and photochemical reactions, the concentrations of some of the OCCs presented their highest levels in the fall. A significant correlation between Acet-A and Buty-A was found at the major fishery facilities （r = 0.816, p = 1.87E-15, n = 60） and at the border areas （r = 0.809, p = 3.40E-12, n = 48） of this fishery industrial complex. The concentrations of OCCs at the border areas were not worse than those at the urban areas in other places, indicating that the concentrations of ambient OCCs at the border areas were not greatly influenced by manmade activities.
基金supported by the National Research Foundation,Singaporeprogram number NRF-CRP5-2009-02,for the School of Civil and Environmental Engineering/Residues and Resource Reclamation Centre,Nanyang Technological University,Singapore
文摘Source separation sanitation systems have attracted more and more attention recently.However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid such issues, it is necessary to monitor the odor related compounds that might be generated during urine storage. This study investigated the odorous compounds that emitted from source-separated human urine under different hydrolysis conditions. Batch experiments were conducted to investigate the effect of temperature, stale/fresh urine ratio and urine dilution on odor emissions. It was found that ammonia, dimethyl disulfide, allyl methyl sulfide and 4-heptanone were the main odorous compounds generated from human urine, with headspace concentrations hundreds of times higher than their respective odor thresholds. Furthermore, the high temperature accelerated urine hydrolysis and liquid–gas mass transfer, resulting a remarkable increase of odor emissions from the urine solution. The addition of stale urine enhanced urine hydrolysis and expedited odor emissions. On the contrary, diluted urine emitted less odorous compounds ascribed to reduced concentrations of odorant precursors. In addition,this study quantified the odor emissions and revealed the constraints of urine source separation in real-world applications. To address the odor issue, several control strategies are recommended for odor mitigation or elimination from an engineering perspective.
基金supported by the National Water Pollution Control and Management Technology Major Project(No.2012ZX07101-010)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2011FBZ07)
文摘The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide （DMS）,dimethyl trisulfide （DMTS）,and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium （NH4＋-N） were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobacterial blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu.
基金supported by the Project of Scientific Research Plan of Science and Technology Commission of Shanghai Municipality(No.17DZ1202404)the National Natural Science Foundation of China(No.51678357,U1662128)National Key Research and Development Program of China(No.2018YFC1900704)。
文摘The explosive increase of construction and demolition waste(CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills(OIL), with organic matters/inert CDW components(O/I) from 5% to 30%, and the control group only with inert components(IL) or organics(OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content(ER_(total)), theory odor concentration(TOC_(total)), and e-nose concentration(ER_(ENC)), and their correlations with waste properties were also analyzed. It was found that the main contributors to ER_(total)(IL: 93.0% NH_(3);OIL: 41.6% sulfides, 31.0% NH_(3), 25.9% oxygenated compounds) and TOC_(total)(IL: 64.1% CH_3SH, 28.2% NH_(3);OIL: 71.7% CH_(3)SH, 24.8% H_(2)S) changed significantly. With the rise of O/I, ER_(total), TOC_(total), and ER_(ENC) increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10%(i.e., DOC < 101.3 mg/L). The good regressions between waste properties(DOC, DN, pH) and ER_(total),( r = 0.86, 0.86,-0.88, p < 0.05), TOC_(total),( r = 0.82, 0.79, -0.82, p < 0.05) implied that the carbon sources and acidic substances relating to organics degradation might result in that increase. Besides, the correlation analysis results( ER_(ENC) vs. TOC_(total,, r = 0.96, p < 0.01;vs. ER_(ENC), r = 0.86, p < 0.05) indicated that e-nose perhaps was a reliable odor continuous monitoring tool for CDW landfills.
