The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Kai Bester - One of the best experts on this subject based on the ideXlab platform.
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Fate of Triclosan and Triclosan-Methyl in Sewage TreatmentPlants and Surface Waters
Archives of Environmental Contamination and Toxicology, 2005Co-Authors: Kai BesterAbstract:The fate of triclosan in diverse stages of two sewage treatment processes has been determined. The elimination process differed considerably depending on the technology applied in the respective sewage treatment plant (STP). The plant operating with a two-stage biologic (activated sludge) process removed triclosan more efficiently than the STP with a combination of physical and activated sludge process. The treatment in the Aeration Basin was the dominant elimination mechanism, whereas the final biologic filter was not very effective. The elimination rates for triclosan were 87% and 95%, respectively. These data were compared with emissions of a multitude of STPs in the river Ruhr catchment area as well as triclosan and its known transformation product, triclosan-methyl, in the river. The concentrations of both compounds were between
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fate of triclosan and triclosan methyl in sewage treatment plants and surface waters
Archives of Environmental Contamination and Toxicology, 2005Co-Authors: Kai BesterAbstract:The fate of triclosan in diverse stages of two sewage treatment processes has been determined. The elimination process differed considerably depending on the technology applied in the respective sewage treatment plant (STP). The plant operating with a two-stage biologic (activated sludge) process removed triclosan more efficiently than the STP with a combination of physical and activated sludge process. The treatment in the Aeration Basin was the dominant elimination mechanism, whereas the final biologic filter was not very effective. The elimination rates for triclosan were 87% and 95%, respectively. These data were compared with emissions of a multitude of STPs in the river Ruhr catchment area as well as triclosan and its known transformation product, triclosan-methyl, in the river. The concentrations of both compounds were between <3 and 10 ng/L in true surface-water samples for triclosan and between 0.3 and 10 ng/L for triclosan-methyl. The STP effluents held higher concentrations (10 to 600 ng/L triclosan). The ratio of triclosan to triclosan-methyl did not change significantly within the longitudinal profile of the river, but diverse STPs discharging to the river exhibited individual triclosan-to-triclosan-methyl ratios. From the riverine concentration data, in-river elimination rates and half-life were estimated.
Timothy Vogel - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of bacterial communities during low temperature thermal treatment of activated sludge combining DNA phylochip and respirometry techniques
Water Research, 2010Co-Authors: Marina Hery, Hervé Sanguin, Sergio Fabiel, Xavier Lefebvre, Timothy VogelAbstract:Sludge reduction is one of the major challenges in biological wastewater treatment. One approach is to increase the sludge degradation yield together with the biodegradation kinetics. Among the various sludge pretreatment strategies proposed, thermal pretreatment at around 65 degrees C was described as promising. The enhancement in the biodegradation activity due to the selection of thermophilic hydrolytic bacteria was proposed, but further experiments are needed to demonstrate the specific role of these bacteria. In this study, concentrated activated sludge grown at 20 C was subjected to thermal treatment at 65 C for different periods. The originality of the work relied on a polyphasic approach based on the correlation between kinetics (chemical oxygen demand, COD; mixed liquor suspended solids, MLSS), bacterial activity (respirometry) and bacterial community structure (phylochip monitoring) in order to characterize the mechanisms involved in the thermal reduction of sludge. The bacterial activity in the Aeration Basin decreased to a very low level when recycling sludge was treated at 65 degrees C from 13 to 60 h, but then, started to increase after 60 h. In parallel to these fluctuations in activity, a drastic shift occurred in the bacterial community structure with the selection of thermophilic bacteria (mainly related to genera Paenibacillus and Bacillus), which are known for their specific hydrolases.
Marina Hery - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of bacterial communities during low temperature thermal treatment of activated sludge combining DNA phylochip and respirometry techniques
Water Research, 2010Co-Authors: Marina Hery, Hervé Sanguin, Sergio Fabiel, Xavier Lefebvre, Timothy VogelAbstract:Sludge reduction is one of the major challenges in biological wastewater treatment. One approach is to increase the sludge degradation yield together with the biodegradation kinetics. Among the various sludge pretreatment strategies proposed, thermal pretreatment at around 65 degrees C was described as promising. The enhancement in the biodegradation activity due to the selection of thermophilic hydrolytic bacteria was proposed, but further experiments are needed to demonstrate the specific role of these bacteria. In this study, concentrated activated sludge grown at 20 C was subjected to thermal treatment at 65 C for different periods. The originality of the work relied on a polyphasic approach based on the correlation between kinetics (chemical oxygen demand, COD; mixed liquor suspended solids, MLSS), bacterial activity (respirometry) and bacterial community structure (phylochip monitoring) in order to characterize the mechanisms involved in the thermal reduction of sludge. The bacterial activity in the Aeration Basin decreased to a very low level when recycling sludge was treated at 65 degrees C from 13 to 60 h, but then, started to increase after 60 h. In parallel to these fluctuations in activity, a drastic shift occurred in the bacterial community structure with the selection of thermophilic bacteria (mainly related to genera Paenibacillus and Bacillus), which are known for their specific hydrolases.
Gülerman Sürücü - One of the best experts on this subject based on the ideXlab platform.
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Effects of Temperature and pH on the Settleability of Activated Sludge Flocs
Water Science and Technology, 1990Co-Authors: F. Dilek Cetin, Gülerman SürücüAbstract:In efficient and economical treatment of wastewaters,the settleability of activated sludge is of prime importance. Efficient settlement in the secondary sedimentation tank is required, both to keep the desired effluent quality and to sustain the necessary amount of microorganisms in the Aeration tank. On the other hand, the settleability of microorganisms in the secondary clarifier is very dependent on the physiological and biochemical nature of activated sludge flocs, which are determined by the conditions of the Aeration tank. In this research, effects of temperature and pH of Aeration Basin on settleability of activated sludge were studied. Settleability was measured by zone settling velocity and sludge volume index (SVI). Five different temperatures and four different pH values were operated in the Aeration Basin. It was found that the settleability of activated sludge is greatly affected by these two parameters.
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Effects of temperature, pH and D. O. concentration on settleability of activated sludge
Environmental Technology, 1990Co-Authors: Gülerman Sürücü, F. Dilck ÇetinAbstract:Abstract In this study, effects of temperature, pH and dissolved oxygen (DO) concentration of Aeration Basin on the settleability of activated sludge were investigated. Settleability was measured in terms of zone settling velocity and sludge volume index (SVI). Semicontinuous reactors were fed with synthetic wastewater. Five different temperatures, four different pH values and five different DO concentrations were operated in the Aeration Basin. It is believed that the information about the effects of these parameters on settleability of activated sludge are very important and must be seriously considered for the system efficiency and economy.
Linsey C. Marr - One of the best experts on this subject based on the ideXlab platform.
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Aerosolization of Ebola Virus Surrogates in Wastewater Systems
Environmental Science & Technology, 2017Co-Authors: Linsey C. MarrAbstract:Recent studies have shown that Ebola virus can persist in wastewater. We evaluated the potential for Ebola virus surrogates to be aerosolized from three types of wastewater systems: toilets, a lab-scale model of an Aeration Basin, and a lab-scale model of converging sewer pipes. We measured the aerosol size distribution generated by each system, spiked Ebola virus surrogates (MS2 and Phi6) into each system, and determined the emission rate of viruses into the air. The number of aerosols released ranged from 105 to 107 per flush from the toilets or per minute from the lab-scale models, and the total volume of aerosols generated by these systems was ∼10–9 to 10–7 mL per flush or per minute in all cases. MS2 and Phi6, spiked into toilets at an initial concentration of 107 plaque-forming units per milliliter (PFU mL–1), were not detected in air after flushing. Airborne concentrations of MS2 and Phi6 were ∼20 PFU L–1 and ∼0.1 PFU L–1, respectively, in the chambers enclosing the Aeration Basin and sewer models....
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Aerosolization of Ebola Virus Surrogates in Wastewater Systems
2017Co-Authors: Kaisen Lin, Linsey C. MarrAbstract:Recent studies have shown that Ebola virus can persist in wastewater. We evaluated the potential for Ebola virus surrogates to be aerosolized from three types of wastewater systems: toilets, a lab-scale model of an Aeration Basin, and a lab-scale model of converging sewer pipes. We measured the aerosol size distribution generated by each system, spiked Ebola virus surrogates (MS2 and Phi6) into each system, and determined the emission rate of viruses into the air. The number of aerosols released ranged from 105 to 107 per flush from the toilets or per minute from the lab-scale models, and the total volume of aerosols generated by these systems was ∼10–9 to 10–7 mL per flush or per minute in all cases. MS2 and Phi6, spiked into toilets at an initial concentration of 107 plaque-forming units per milliliter (PFU mL–1), were not detected in air after flushing. Airborne concentrations of MS2 and Phi6 were ∼20 PFU L–1 and ∼0.1 PFU L–1, respectively, in the chambers enclosing the Aeration Basin and sewer models. The corresponding emission rates of MS2 and Phi6 were 547 PFU min–1 and 3.8 PFU min–1, respectively, for the Aeration Basin and 79 PFU min–1 and 0.3 PFU min–1 for the sewer pipes
