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Li Y, He Y, Guo H, Hou J, Dai S, Zhang P, Tong Y, Ni BJ, Zhu T, Liu Y. Sulfur-containing substances in sewers: Transformation, transportation, and remediation. JOURNAL OF HAZARDOUS MATERIALS 2024; 467:133618. [PMID: 38335612 DOI: 10.1016/j.jhazmat.2024.133618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/10/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Abstract
Sulfur-containing substances in sewers frequently incur unpleasant odors, corrosion-related economic loss, and potential human health concerns. These observations are principally attributed to microbial reactions, particularly the involvement of sulfate-reducing bacteria (SRB) in sulfur reduction process. As a multivalent element, sulfur engages in complex bioreactions in both aerobic and anaerobic environments. Organic sulfides are also present in sewage, and these compounds possess the potential to undergo transformation and volatilization. In this paper, a comprehensive review was conducted on the present status regarding sulfur transformation, transportation, and remediation in sewers, including both inorganic and organic sulfur components. The review extensively addressed reactions occurring in the liquid and gas phase, as well as examined detection methods for various types of sulfur compounds and factors affecting sulfur transformation. Current remediation measures based on corresponding mechanisms were presented. Additionally, the impacts of measures implemented in sewers on the subsequent wastewater treatment plants were also discussed, aiming to attain better management of the entire wastewater system. Finally, challenges and prospects related to the issue of sulfur-containing substances in sewers were proposed to facilitate improved management and development of the urban water system.
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Affiliation(s)
- Yiming Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Jiaqi Hou
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Suwan Dai
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Peiyao Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
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Jana S, Basu S, Sarkar U. Odour impact assessment using kinetics and optimization: case studies on removal of multiple volatile organo-sulphur compounds from sewage wastewater using porous functional materials. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 195:226. [PMID: 36562856 DOI: 10.1007/s10661-022-10828-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Expanding industries and booming population have led to the increase in the installation of wastewater and sewer systems, even in close proximity to residential areas. Emissions from these installations particularly volatile organo-sulphur compounds (VOSCs) such as methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), dimethyl sulphide (CH3SCH3) and carbon disulphide (CS2) are a nuisance to people even when present in small concentration. Strategies for removal involve addition of chemicals or other chemical processes which are generally expensive. Biofilters, on the other hand, consume large amount of energy and wash waters. Hence keeping commercialization in mind, it is important to develop a strategy which would be cost-effective and at the same time be effective to remove most of the odorous compounds present in these systems. In the present research work, granular activated carbons (GAC) are functionalized with alkali solution to improve the adsorption capacity. Liquid phase batch adsorption is performed with GAC and various functionalized activated carbons (FACs) with the help of raw sewage water from a local sewage water treatment plant. Concentration of odour was evaluated by two methods-olfactometry-based analysis for sensory measurement and GCMS-based analysis for analytical estimation of a specific odorous compound. The adsorption capacities of the functionalized GACs are higher primarily because of complex formation at the surface of modified GACs. Pseudo-second-order kinetic model agreed well with experimental results with the rate constant being 0.0191 mg/l min and 0.0153 mg/l min for methyl and ethyl mercaptan adsorption onto FAC-NH3. Boyd's film diffusion along with rate kinetic model supported that chemical adsorption forms the rate-limiting step. Response surface methodology (RSM) was used to optimize the removal of VOSCs with respect to different process parameters like adsorbent amount and time. The olfactometry removal of overall odour was also optimized taking 6 factors in the Box Behnken design. Variance of analysis results indicated that all the models displayed considerable goodness of fit with R2 values close to 1. Methyl mercaptan turned out to be the highest contributor to the overall odour as confirmed both from experimental and optimization study. The optimized olfactometry odour removal (77.4%) along with CH3SH removal (80.34%), C2H5SH removal (59.16%), CH3SCH3 removal (63.21%) and CS2 removal (71.95%) was found at optimum process conditions, with amount of adsorbent of 10.29 g, adsorption time of 2.92 h. This result indicates that methyl mercaptan (CH3SH) is the highest odour contributing component out of the studied VOSCs. The results show promising potential for the use of activated carbon as an adsorbent for removal of odorous compounds from STPs.
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Affiliation(s)
- Shyamal Jana
- Chemical Engineering Department, Jadavpur University, Kolkata, 700032, India
| | - Sankhadeep Basu
- Chemical Engineering Department, Jadavpur University, Kolkata, 700032, India
| | - Ujjaini Sarkar
- Chemical Engineering Department, Jadavpur University, Kolkata, 700032, India.
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Elzinga M, Zamudio J, van Bovenkaarsmaker S, Pol TVD, Klok J, Heijne AT. A simple method for routine measurement of organosulfur compounds in complex liquid and gaseous matrices. J Chromatogr A 2022; 1677:463276. [DOI: 10.1016/j.chroma.2022.463276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022]
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Barczak RJ, Fisher RM, Le-Minh N, Stuetz RM. Identification of volatile sulfur odorants emitted from ageing wastewater biosolids. CHEMOSPHERE 2022; 287:132210. [PMID: 34826912 DOI: 10.1016/j.chemosphere.2021.132210] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
Volatile sulfur compounds (VSCs) are important sources of unpleasant odours in biosolid emissions. However, the study of VSCs may be limited by complications in their gas phase measurements due to reactivity, transformations and varying reported odour detection thresholds. A range of methods were used to quantitatively analyse VSCs in wastewater biosolid emissions. VSCs were identified in aged biosolid emissions by gas chromatography (GC) with a sulfur chemiluminescence detector (SCD) and mass spectrometry coupled with olfactory detection port (MS/O). In total, 10 VSC's were identified with two volatile organic sulfur compounds (VOSCs), allyl methyl sulfide and methyl propyl sulfide being reported for the first time in biosolid emissions. The emission patterns of different VSCs varied as the biosolids aged. Initially, the median concentrations of H2S, dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), methanethiol (MeSH) and ethanethiol (EtSH) were orders of magnitude greater than their reported odour detection threshold, suggesting they would contribute to the odorous impact of the biosolids. The maximum H2S value was equal to 59.9 × 103 μg/m3 and was at least one magnitude higher compared to VOSCs, such as dimethyl disulfide (DMDS) (3.8×103 μg/m3), DMS (4.53 × 103 μg/m3), EtSH (2.83 × 103 μg/m3) and MeSH (3.25 × 103 μg/m3). Among the identified VSCs, H2S was the prominent odorant in terms of the magnitude and the frequency of detection, both initially as well as throughout storage. However, DMTS should be considered as a high priority or key odorant due to its odour activity value (OAV) and frequency of detection (sensorially detected in more than 75% of samples, with an OAVs higher than 1).
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Affiliation(s)
- Radosław J Barczak
- Faculty of Building Services, Hydro and Environmental Engineering, Warsaw University of Technology, Nowowiejska 20 Street, 00-653, Warsaw, Poland; UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Ruth M Fisher
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Nhat Le-Minh
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Richard M Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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Wang X, Le M, Stuetz R. Calibration methods for VSCs measured on AS-TD-GC-SCD. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 194:25. [PMID: 34905118 DOI: 10.1007/s10661-021-09690-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Volatile sulfur compounds (VSCs) are key odorous compounds from emissions of various odour sources because they are odorous and generally have very low odour threshold values. Identification and quantification of them through air server-thermal desorber-gas chromatography-sulfur chemiluminescence detector (AS-TD-GC-SCD) become more and more popular, although VSCs can be determined by other detectors. To find a valid, practical and quick calibration method is also an important step in their analytical processes. This study compared three different sample preparation and unity sampling methods using both gas standards (with 10 VSCs balanced in pure nitrogen gas) and liquid standards of 7 VSCs. For liquid standard sample preparation, two solvents (methanol and n-pentane) were tested and their calibration results were compared. The study revealed that the three calibration methods with both manual and dynamic dilution of VSC standard gases can achieve satisfactory calibration results with nice linear regression and correlation coefficient (r2). The dynamic dilution and loop sampling method is recommended because of its better reliability and time-saving processing. For calibration of VSCs with liquid standards, preparing the samples using dissolved VSCs in n-pentane and analysing them using the loop sampling method achieved best calibration results. For dimethyl trisulfide (DMTS), its calibration cannot obtain as good results as other sulfur compounds even using the best performance calibration method.
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Affiliation(s)
- Xinguang Wang
- Water Research Centre, University of New South Wales, Sydney, 2052, Australia.
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu Province, China.
| | - Minh Le
- Water Research Centre, University of New South Wales, Sydney, 2052, Australia
| | - Richard Stuetz
- Water Research Centre, University of New South Wales, Sydney, 2052, Australia
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Yu P, Yang Y, Sun J, Jia X, Zheng C, Zhou Q, Huang F. Identification of volatile sulfur-containing compounds and the precursor of dimethyl sulfide in cold-pressed rapeseed oil by GC-SCD and UPLC-MS/MS. Food Chem 2021; 367:130741. [PMID: 34399272 DOI: 10.1016/j.foodchem.2021.130741] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/19/2021] [Accepted: 07/29/2021] [Indexed: 11/25/2022]
Abstract
Volatile sulfur-containing compounds (VSCs) provide an important contribution to foods due to their special odors. In this study, VSCs in 21 cold-pressed rapeseed oils (CROs) from 9 regions in China were extracted and separated by headspace solid-phase microextraction combined with gas chromatography coupled with sulfur chemiluminescence detection. 19 VSCs were identified by authentic standards, and the total concentration of VSCs in all CROs ranged from 49.0 to 18129 μg/kg. Dimethyl sulfide (DMS), with its high odor activity value (7-14574), was the most significant aroma contributor to the CROs. Furthermore, S-methylmethionine (SMM) in rapeseed was first affirmed by ultra-performance liquid chromatography-tandem mass spectrometry and isotope quantitation. The positive correlation coefficient between DMS and SMM was 0.793 (p < 0.05), which confirmed SMM as a crucial precursor of DMS in CROs. This study provided a theoretical basis for selecting rapeseed materials by the distribution of essential VSCs and the source of DMS.
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Affiliation(s)
- Pei Yu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China
| | - Yini Yang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China
| | - Jinyuan Sun
- Beijing Key Laboratory of Flavor Chemistry, Beijing Technology and Business University (BTBU), Beijing 100048, China
| | - Xiao Jia
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China
| | - Chang Zheng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China
| | - Qi Zhou
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China.
| | - Fenghong Huang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Lipid Chemistry and Nutrition, and Key Laboratory of Oilseeds Processing, Ministry of Agriculture, Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, China.
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Han Z, Li R, Shen H, Qi F, Liu B, Shen X, Zhang L, Wang X, Sun D. Emission characteristics and assessment of odors from sludge anaerobic digestion with thermal hydrolysis pretreatment in a wastewater treatment plant. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 274:116516. [PMID: 33529890 DOI: 10.1016/j.envpol.2021.116516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/30/2020] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Anaerobic digestion (AD) with thermal hydrolysis pre-treatment (THP) is an effective sludge treatment method which provides several advantages such as enhanced biogas formation and fertilizer production. The main limitation to THP-AD is that hazardous odors, including NH3 and volatile sulfur compounds (VSCs), are emitted during the sludge treatment process. In order to develop strategies to eliminate odors, it is necessary to identify the key odors and emissions sites. This study identified production of NH3 (741.60 g·dry sludge t-1) and VSCs (277.27 g·dry sludge t-1) during sludge AD after THP, and measured emissions in each of the THP-AD sludge treatment sites. Odor intensity, odor active values, permissible concentration-time weighted average, and non-carcinogenic risks were also assessed in order to determine the sensory impact, odor contribution, and health impacts of NH3 and VSCs. The results revealed that odor pollution existed in all of the test sites, particularly in the sludge pump room and pre-dehydration workshop. NH3, H2S, and methyl mercaptan caused very strong odors, and levels of NH3 and H2S were enough to impact the health of on-site employees.
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Affiliation(s)
- Zhangliang Han
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing, 100083, China; College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Ruoyu Li
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Hanzhang Shen
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Fei Qi
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing, 100083, China
| | - Baoxian Liu
- Beijing Municipal Ecological and Environmental Monitoring Center, Beijing, 100048, China; Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology, Beijing, 100048, China
| | - Xiue Shen
- Beijing Municipal Ecological and Environmental Monitoring Center, Beijing, 100048, China; Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology, Beijing, 100048, China
| | - Lin Zhang
- Beijing Municipal Ecological and Environmental Monitoring Center, Beijing, 100048, China; Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology, Beijing, 100048, China
| | - Xiaoju Wang
- Beijing Municipal Ecological and Environmental Monitoring Center, Beijing, 100048, China; Beijing Key Laboratory of Airborne Particulate Matter Monitoring Technology, Beijing, 100048, China
| | - Dezhi Sun
- Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing, 100083, China.
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Automated, high frequency, on-line dimethyl sulfide measurements in natural waters using a novel "microslug" gas-liquid segmented flow method with chemiluminescence detection. Talanta 2021; 221:121595. [PMID: 33076129 DOI: 10.1016/j.talanta.2020.121595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 11/22/2022]
Abstract
Dimethyl sulfide (DMS) is the major biogenic volatile sulfur compound in surface seawater. Good quality DMS data with high temporal and spatial resolution are desirable for understanding reduced sulfur biogeochemistry. Here we present a fully automated and novel "microslug" gas-liquid segmented flow-chemiluminescence (MSSF-CL) based method for the continuous in-situ measurement of DMS in natural waters. Samples were collected into a flow tank and DMS transferred from the aqueous phase to the gas phase using a vario-directional coiled flow, in which microvolume liquid and gas slugs were interspersed. The separated DMS was reacted with ozone in a reaction cell for CL detection. The analytical process was automated, with a sample throughput of 6.6 h-1. Using MSSF for DMS separation was more effective and easily integrated with CL detection compared with the commonly used bubbling approach. Key parameters of the proposed method were investigated. The linear range for the method was 0.05-500 nM (R2 = 0.9984) and the limit of detection (3 x S/N) was 0.015 nM, which is comparable to the commonly used gas chromatography (GC) method and sensitive enough for direct DMS measurement in typical aquatic environments. Reproducibility and recovery were assessed by spiking natural water samples (river, lake, reservoir and pond) with different concentrations of DMS (10, 20 and 50 nM), giving relative standard deviations (RSDs) ≤1.75% (n = 5) and recoveries of 94.4-107.8%. This fully automated system is reagent free, easy to assemble, simple to use, portable (weight ~5.1 kg) and can be left in the field for several hours of unattended operation. The instrumentation can provide high quality DMS data for natural waters with an environmentally relevant temporal resolution of ~9 min.
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Evaluation of Reductions in Fume Emissions (VOCs and SVOCs) from Warm Mix Asphalt Incorporating Natural Zeolite and Reclaimed Asphalt Pavement for Sustainable Pavements. SUSTAINABILITY 2020. [DOI: 10.3390/su12229546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Conventional asphalt mixtures used for road paving require high manufacturing temperatures and therefore high energy expenditure, which has a negative environmental impact and creates risk in the workplace owing to high emissions of pollutants, greenhouse gases, and toxic fumes. Reducing energy consumption and emissions is a continuous challenge for the asphalt industry. Previous studies have focused on the reduction of emissions without characterizing their composition, and detailed characterization of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) in asphalt fumes is scarce. This communication describes the characterization and evaluation of VOCs and SVOCs from asphalt mixtures prepared at lower production temperatures using natural zeolite; in some cases, reclaimed asphalt pavement (RAP) was used. Fumes were extracted from different asphalt mix preparations using a gas syringe and then injected into hermetic gas sample bags. The compounds present in the fumes were sampled with a fiber and analyzed by gas-liquid chromatography coupled to mass spectrometry (GC/MS). In general, the preparation of warm mix asphalts (WMA) using RAP and natural zeolite as aggregates showed beneficial effects, reducing VOCs and SVOCs compared to hot mix asphalts (HMA). The fumes captured presented a similar composition to those from HMA, consisting principally of saturated and unsaturated aliphatic hydrocarbons and aromatic compounds but with few halogenated compounds and no polycyclic aromatic hydrocarbons. Thus, the paving mixtures described here are a friendlier alternative for the environment and for the health of road workers, in addition to permitting the re-use of RAP.
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Chen Y, Li J, Hou X, Zhang X, Yin H, Zhang M, Zheng C. Trapping and preconcentration of volatile organic sulfur compounds in water samples by portable and battery-powered trapping device prior to gas chromatography-sulfur chemiluminescence determination. J Chromatogr A 2020; 1619:460947. [PMID: 32268954 DOI: 10.1016/j.chroma.2020.460947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
Abstract
A simple, portable and battery-powered trapping device (iTrap) consisting of a purification tube, a trapping unit and a miniature air pump was developed for the pre-concentration of volatile organic sulfur compounds (VOSCs). The tested VOSCs, including methanthiol (MT), ethanethiol (ET), dimethyl sulfide (DMS), diethyl sulfide (DES) and dimethyl disulfide (DMDS), were firstly purged from water samples and then in situ pre-concentrated with the iTrap prior to their analysis by thermal desorption gas chromatography coupling with a sulfur chemiluminescence detector (TD-GC-SCD). Twenty-six adsorbents were studied to find the most suitable adsorbent for the efficient pre-concentration of VOSCs. Under optimal conditions, limits of detection of 6, 8, 6, 2 and 3 ng L-1 were obtained for MT, ET, DMS, DES and DMDS, respectively. The precisions were better than 5.3% (relative standard deviations, RSDs). The iTrap was successfully applied for the analysis of VOSCs in Certified Reference Materials, several surface water, underground water and wastewater samples collected from Pengzhou city, Sichuan, China. Moreover, the VOSCs trapped in the iTrap were much more stable than those directly stored in water samples and the recoveries for all samples could be maintained at acceptable levels (>73%), even their preservation time as long as 8 h.
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Affiliation(s)
- Yong Chen
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan 610066, China
| | - Jia Li
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan 610066, China
| | - Xiaoling Hou
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan 610066, China
| | - Xiaoxu Zhang
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan 610066, China
| | - Hui Yin
- Chengdu Environmental Monitoring Center, Chengdu, Sichuan 610066, China
| | - Min Zhang
- School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China
| | - Chengbin Zheng
- Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
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Cämmerer M, Mayer T, Penzel S, Rudolph M, Borsdorf H. Application of Low-Cost Electrochemical Sensors to Aqueous Systems to Allow Automated Determination of NH 3 and H 2S in Water. SENSORS (BASEL, SWITZERLAND) 2020; 20:E2814. [PMID: 32429188 PMCID: PMC7284547 DOI: 10.3390/s20102814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 11/17/2022]
Abstract
Usage of commercially available electrochemical gas sensors is currently limited by both the working range of the sensor with respect to temperature and humidity and the spikes in sensor response caused by sudden changes in temperature or humidity. Using a thermostatically controlled chamber, the sensor response of ammonia and hydrogen sulfide sensors was studied under extreme, rapidly changing levels of humidity with the aim of analyzing nebulized water samples. To protect the sensors from damage, the gas stream was alternated between a saturated gas stream from a Flow Blurring® nebulizer and a dry air stream. When switching between high and low humidity gas streams, the expected current spike was observed and mathematically described. Using this mathematical model, the signal response due to the change in humidity could be subtracted from the measured signal and the sensor response to the target molecule recorded. As the sensor response is determined by the model while the sensor is acclimatizing to the new humid conditions, a result is calculated faster than that by systems that rely on stable humidity. The use of the proposed mathematical model thus widens the scope of electrochemical gas sensors to include saturated gas streams, for example, from nebulized water samples, and gas streams with variable humidity.
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Affiliation(s)
- Malcolm Cämmerer
- UFZ—Helmholtz Centre for Environmental Research GmbH, Department Monitoring and Exploration Technologies, Permoserstraße 15, D-04318 Leipzig, Germany; (T.M.); (H.B.)
| | - Thomas Mayer
- UFZ—Helmholtz Centre for Environmental Research GmbH, Department Monitoring and Exploration Technologies, Permoserstraße 15, D-04318 Leipzig, Germany; (T.M.); (H.B.)
| | - Stefanie Penzel
- Faculty of Engineering, Leipzig University of Applied Science, Karl-Liebknecht-Str. 134, D-04277 Leipzig, Germany; (S.P.); (M.R.)
| | - Mathias Rudolph
- Faculty of Engineering, Leipzig University of Applied Science, Karl-Liebknecht-Str. 134, D-04277 Leipzig, Germany; (S.P.); (M.R.)
| | - Helko Borsdorf
- UFZ—Helmholtz Centre for Environmental Research GmbH, Department Monitoring and Exploration Technologies, Permoserstraße 15, D-04318 Leipzig, Germany; (T.M.); (H.B.)
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12
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Liang Z, Siegert M, Fang W, Sun Y, Jiang F, Lu H, Chen GH, Wang S. Blackening and odorization of urban rivers: a bio-geochemical process. FEMS Microbiol Ecol 2019; 94:4780270. [PMID: 29293959 DOI: 10.1093/femsec/fix180] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 12/23/2017] [Indexed: 11/14/2022] Open
Abstract
Urban rivers constitute a major part of urban drainage systems, and play critical roles in connecting other surface waters in urban areas. Black-odorous urban rivers are widely found in developing countries experiencing rapid urbanization, and the mismatch between urbanization and sewage treatment is thought to be the reason. The phenomena of blackening and odorization are likely complex bio-geochemical processes of which the microbial interactions with the environment are not fully understood. Here, we provide an overview of the major chemical compounds, such as iron and sulfur, and their bio-geochemical conversions during blackening and odorization of urban rivers. Scenarios explaining the formation of black-odorous urban rivers are proposed. Finally, we point out knowledge gaps in mechanisms and microbial ecology that need to be addressed to better understand the development of black-odorous urban rivers.
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Affiliation(s)
- Zhiwei Liang
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China
| | - Michael Siegert
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China.,Department of Geoscience, University of Calgary, Calgary, Canada
| | - Wenwen Fang
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China
| | - Yu Sun
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China
| | - Feng Jiang
- School of Chemistry and Environment, South China Normal University, Guangzhou, China
| | - Hui Lu
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China
| | - Guang-Hao Chen
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Shanquan Wang
- Environmental Microbiome Research Center and the School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, China
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13
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Blanco-Rodríguez A, Camara VF, Campo F, Becherán L, Durán A, Vieira VD, de Melo H, Garcia-Ramirez AR. Development of an electronic nose to characterize odours emitted from different stages in a wastewater treatment plant. WATER RESEARCH 2018; 134:92-100. [PMID: 29407655 DOI: 10.1016/j.watres.2018.01.067] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/22/2018] [Accepted: 01/27/2018] [Indexed: 05/26/2023]
Abstract
Wastewater treatment plants have widely been described as a significant source of odour nuisance, which has led to an increase of neighbourhood complaints. Therefore, to mitigate the negative impact of odours, the detection and analysis of these emissions are required. This paper presents a measurement system based on an electronic nose for quantitative and qualitative odour analysis of samples collected from six different stages on a wastewater plant. Hence, two features vectors were performed in order to represent quantitative trends of the gaseous mixture sampled on the facility. In addition, odour fingerprints and a PCA were computed to discriminate odours from its sources and to detect relationships among the samples. This approach also comprises a dynamic dilution olfactometer. A PLS regression model was performed to predict the odour concentration by the electronic nose in term of odour units per cubic meter. The results show that the developed electronic nose is a promising and feasible instrument to characterize odours from wastewater plants.
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Affiliation(s)
- Andy Blanco-Rodríguez
- Laboratory of Air Quality Control (LCQAr), Department of Sanitary and Environmental Engineering (ENS), Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil.
| | | | - Fernando Campo
- Centro Em Ciências Tecnológicas da Terra e Do Mar (CTTMar), Universidade Do Vale Do Itajaí (UNIVALI), 88302-202, Itajaí, SC, Brazil.
| | - Liliam Becherán
- Institute of Materials Science and Technology (IMRE), University of Havana, 10400, Havana, Cuba.
| | - Alejandro Durán
- Institute of Materials Science and Technology (IMRE), University of Havana, 10400, Havana, Cuba.
| | - Vitor Debatin Vieira
- Laboratório de Eletroforese Capilar (LabEC), Departamento de Química, Universidade Federal de Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil.
| | - Henrique de Melo
- Laboratory of Air Quality Control (LCQAr), Department of Sanitary and Environmental Engineering (ENS), Federal University of Santa Catarina (UFSC), 88040-900, Florianópolis, SC, Brazil.
| | - Alejandro Rafael Garcia-Ramirez
- Centro Em Ciências Tecnológicas da Terra e Do Mar (CTTMar), Universidade Do Vale Do Itajaí (UNIVALI), 88302-202, Itajaí, SC, Brazil.
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14
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Zavahir JS, Nolvachai Y, Marriott PJ. Molecular spectroscopy – Information rich detection for gas chromatography. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2017.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Chen DZ, Zhao XY, Miao XP, Chen J, Ye JX, Cheng ZW, Zhang SH, Chen JM. A solid composite microbial inoculant for the simultaneous removal of volatile organic sulfide compounds: Preparation, characterization, and its bioaugmentation of a biotrickling filter. JOURNAL OF HAZARDOUS MATERIALS 2018; 342:589-596. [PMID: 28892796 DOI: 10.1016/j.jhazmat.2017.08.079] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/30/2017] [Accepted: 08/31/2017] [Indexed: 06/07/2023]
Abstract
Volatile organic sulfide compounds (VOSCs) are usually resistant to biodegradation, thereby limiting the performance of traditional biotechnology dealing with waste gas containing such pollutants especially in mixture. In this study, a solid composite microbial inoculant (SCMI) was prepared to remove dimethyl sulfide (DMS) and propanethiol (PT). Given that the DMS degradation activity of Alcaligenes sp. SY1 is inducible and the PT-degradation activity of Pseudomonas putida S-1 is constitutive, different strategies are designed for cell cultivation to obtain high VOSC removal rates of SCMI. Compared with the microbial suspension, the prepared SCMI exhibited better storage stability at 4 and 25°C. Inoculation of the SCMI in biotrickling filters (BTFs) could effectively shorten the start-up period and enhance the removal performance. Microbial analysis by Illumina MiSeq indicated that Alcaligenes sp. SY1 and P. putida S-1 might be dominant and persistent among the microbial communities of the BTF during the operation.
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Affiliation(s)
- Dong-Zhi Chen
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China.
| | - Xiang-Yu Zhao
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiao-Ping Miao
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Jing Chen
- College of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316004, China
| | - Jie-Xu Ye
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhuo-Wei Cheng
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Shi-Han Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Jian-Meng Chen
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
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16
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Boczkaj G, Makoś P, Fernandes A, Przyjazny A. New procedure for the control of the treatment of industrial effluents to remove volatile organosulfur compounds. J Sep Sci 2016; 39:3946-3956. [DOI: 10.1002/jssc.201600608] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Grzegorz Boczkaj
- Department of Chemical and Process Engineering, Chemical Faculty; Gdansk University of Technology; Poland
| | - Patrycja Makoś
- Department of Chemical and Process Engineering, Chemical Faculty; Gdansk University of Technology; Poland
| | - André Fernandes
- Department of Chemical and Process Engineering, Chemical Faculty; Gdansk University of Technology; Poland
| | - Andrzej Przyjazny
- Department of Chemistry & Biochemistry; Kettering University; Flint MI USA
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17
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Li T, Guo Y, Hu H, Zhang X, Jin Y, Zhang X, Zhang Y. Determination of volatile chlorinated hydrocarbons in water samples by static headspace gas chromatography with electron capture detection. J Sep Sci 2016; 39:358-66. [PMID: 26805957 DOI: 10.1002/jssc.201500771] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 11/11/2022]
Abstract
A simple, efficient, solvent-free, and commercial readily available approach for determination of five volatile chlorinated hydrocarbons in water samples using the static headspace sampling and gas chromatography with electron capture detection has been described. The proposed static headspace sampling method was initially optimized and the optimum experimental conditions found were 10 mL water sample containing 20% w/v sodium chloride placed in a 20 mL vial and stirred at 50ºC for 20 min. The linearity of the method was in the range of 1.2-240 μg/L for dichloromethane, 0.2-40 μg/L for trichloromethane, 0.005-1 μg/L for perchloromethane, 0.025-5 μg/L for trichloroethylene, and 0.01-2 μg/L for perchloroethylene, with coefficients of determination ranging between 0.9979 and 0.9990. The limits of detection were in the low μg/L level, ranging between 0.001 and 0.3 μg/L. The relative recoveries of spiked five volatile chlorinated hydrocarbons with external calibration method at different concentration levels in pure, tap, sea water of Jiaojiang Estuary, and sea water of waters of Xiaomendao were in the range of 91-116, 96-105, 86-112, and 80-111%, respectively, and with relative standard deviations of 1.9-3.6, 2.3-3.5, 1.5-2.7, and 2.3-3.7% (n = 5), respectively. The performance of the proposed method was compared with traditional liquid-liquid extraction on the real water samples (i.e., pure, tap, and sea water, etc.) and comparable efficiencies were obtained. It is concluded that this method can be successfully applied for the determination of volatile chlorinated hydrocarbons in different water samples.
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Affiliation(s)
- Tiejun Li
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
| | - Yuanming Guo
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
| | - Hongmei Hu
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
| | - Xiaoning Zhang
- Department of Mathematics, Sciences & Technology, Paine College, Augusta, Georgia, United States
| | - Yanjian Jin
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
| | - Xiaojun Zhang
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
| | - Yurong Zhang
- Key Laboratory of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan, China
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18
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Jiang G, Sun J, Sharma KR, Yuan Z. Corrosion and odor management in sewer systems. Curr Opin Biotechnol 2015; 33:192-7. [DOI: 10.1016/j.copbio.2015.03.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 10/23/2022]
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19
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Sun J, Hu S, Sharma KR, Ni BJ, Yuan Z. Degradation of methanethiol in anaerobic sewers and its correlation with methanogenic activities. WATER RESEARCH 2015; 69:80-89. [PMID: 25437340 DOI: 10.1016/j.watres.2014.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 05/07/2023]
Abstract
Methanethiol (MT) is considered one of the predominant odorants in sewer systems. Therefore, understanding MT transformation in sewers is essential to sewer odor assessment and abatement. In this study, we investigated the degradation of MT in laboratory anaerobic sewers. Experiments were carried out in seven anaerobic sewer reactors with biofilms at different stages of development. MT degradation was found to be strongly dependent on the methanogenic activity of sewer biofilms. The MT degradation rate accelerated with the increase of methanogenic activity of sewer biofilms, resulting in MT accumulation (i.e. net production) in sewer reactors with relatively low methanogenic activities, and MT removal in reactors with higher methanogenic activities. A Monod-type kinetic expression was developed to describe MT degradation kinetics in anaerobic sewers, in which the maximum degradation rate was modeled as a function of the maximum methane production rate through a power function. It was also found that MT concentration had a linear relationship with acetate concentration, which may be used for preliminary assessment of MT presence in anaerobic sewers.
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Affiliation(s)
- Jing Sun
- Advanced Water Management Centre, The University of Queensland, St. Lucia 4072, Queensland, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, St. Lucia 4072, Queensland, Australia
| | - Keshab Raj Sharma
- Advanced Water Management Centre, The University of Queensland, St. Lucia 4072, Queensland, Australia
| | - Bing-Jie Ni
- Advanced Water Management Centre, The University of Queensland, St. Lucia 4072, Queensland, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia 4072, Queensland, Australia.
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20
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Determination of VOSCs in sewer headspace air using TD-GC-SCD. Talanta 2015; 137:71-9. [PMID: 25770608 DOI: 10.1016/j.talanta.2014.11.072] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/06/2014] [Accepted: 11/07/2014] [Indexed: 11/22/2022]
Abstract
The management of odorous emissions from sewer networks has become an important issue for sewer operators resulting in the need to better understand the composition of volatile organic sulfur compounds (VOSCs). In order to characterise the composition of such malodorous emissions, a method based on thermal desorption (TD) and gas chromatography coupled to sulfur chemiluminescence detector (GC-SCD) has been developed to determine a broader range of VOSCs, hydrogen sulfide (H2S), methanethiol (MeSH), ethanethiol (EtSH), dimethyl sulfide (DMS), carbon disulfide (CS2), ethylmethyl sulfide (EMS), 1-butanethiol (1-BuSH), dimethyl disulfide (DMDS), diethyl disulfide (DEDS), and dimethyl trisulfide (DMTS). Parameters affecting the chromatographic behaviour of the target compounds were studied (e.g., temperature program, carrier gas velocity) as well as the experimental conditions affecting the adsorption/desorption process (temperature, flow and time). Optimised extraction of VOSCs samples was achieved under adsorption temperatures of less than -20°C, and a desorption flow rate of ~6 ml/min. Active collection on the cold trap enabled a small gas volume of 50-100ml to be sampled for all analytes without breakthrough. Calibration curves were derived at different TD loading volumes with determined linearity ranging between 0.09 ng and 60.1 ng. The method detection limits (MDLs) were in the range of 0.10-5.26 μg/m(3) with TD recoveries higher than 66% and reproducibility (relative standard deviation values) between 1.8% and 6.1% being obtained for all compounds. The VOSCs characterisation at different sewerage collection sites in Sydney, Australia (for seasonal, weekly and diurnal) showed that six of the ten targeted compounds were consistently detected at all sample events. Diurnal patterns of VOSCs investigated were clearly observed with the highest concentration occurring after 12 pm (noon) for H2S and MeSH. The consecutive 5 day analysis showed no significant difference in the targeted VOSCs concentrations and demonstrated the suitability of the method for routine sewer VOSCs emission measurements.
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21
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Stratified microbial structure and activity in sulfide- and methane-producing anaerobic sewer biofilms. Appl Environ Microbiol 2014; 80:7042-52. [PMID: 25192994 DOI: 10.1128/aem.02146-14] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Simultaneous production of sulfide and methane by anaerobic sewer biofilms has recently been observed, suggesting that sulfate-reducing bacteria (SRB) and methanogenic archaea (MA), microorganisms known to compete for the same substrates, can coexist in this environment. This study investigated the community structures and activities of SRB and MA in anaerobic sewer biofilms (average thickness of 800 μm) using a combination of microelectrode measurements, molecular techniques, and mathematical modeling. It was seen that sulfide was mainly produced in the outer layer of the biofilm, between the depths of 0 and 300 μm, which is in good agreement with the distribution of SRB population as revealed by cryosection-fluorescence in situ hybridization (FISH). SRB had a higher relative abundance of 20% on the surface layer, which decreased gradually to below 3% at a depth of 400 μm. In contrast, MA mainly inhabited the inner layer of the biofilm. Their relative abundances increased from 10% to 75% at depths of 200 μm and 700 μm, respectively, from the biofilm surface layer. High-throughput pyrosequencing of 16S rRNA amplicons showed that SRB in the biofilm were mainly affiliated with five genera, Desulfobulbus, Desulfomicrobium, Desulfovibrio, Desulfatiferula, and Desulforegula, while about 90% of the MA population belonged to the genus Methanosaeta. The spatial organizations of SRB and MA revealed by pyrosequencing were consistent with the FISH results. A biofilm model was constructed to simulate the SRB and MA distributions in the anaerobic sewer biofilm. The good fit between model predictions and the experimental data indicate that the coexistence and spatial structure of SRB and MA in the biofilm resulted from the microbial types and their metabolic transformations and interactions with substrates.
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