The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David A Dzombak - One of the best experts on this subject based on the ideXlab platform.
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corrosion management in power plant cooling systems using Tertiary treated municipal wastewater as makeup water
Corrosion Science, 2012Co-Authors: Mahbuboor Rahman Choudhury, Radisav D. Vidic, Mingkai Hsieh, David A DzombakAbstract:Abstract Additional Tertiary treatment of secondary-treated municipal wastewater (MWW) is necessary to reduce its scaling potential for use in power plant cooling systems. In this study corrosiveness of three Tertiary-treated municipal wastewaters (acidified MWW, MWW treated by nitrification–filtration, and MWW treated by nitrification–filtration and granular activated carbon adsorption) towards mild steel, copper, and cupronickel alloys was assessed. pH, ammonia, and organic matter were identified as important corrosion influencing parameter in Tertiary-treated municipal wastewater. Corrosiveness of wastewater towards metal alloys increased after Tertiary treatments. However, corrosion of mild steel and copper alloys was controlled within acceptable limits using the corrosion inhibitor tolyltriazole.
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Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management
2012Co-Authors: David A Dzombak, Radisav D. Vidic, Amy E. LandisAbstract:Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing Tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different Tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various Tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three Tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to bemore » significantly enhanced with Tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the Tertiary treated waters. For MWW_NF treated water, the removal of ammonia by nitrification helped to reduce the corrosivity and biocide demand. Also, the lower pH and alkalinity resulting from nitrification reduced the scaling to an acceptable level, without the addition of anti-scalant chemicals. Additional GAC adsorption treatment, MWW_NFG, yielded no net benefit. Removal of organic matter resulted in pitting corrosion in copper and cupronickel alloys. Negligible improvement was observed in scaling control and biofouling control. For all of the Tertiary treatments, biofouling control was achievable, and most effectively with pre-formed monochloramine (2-3 ppm) in comparison with NaOCl and ClO2. Life cycle cost (LCC) analyses were performed for the Tertiary treatment systems studied experimentally and for several other treatment options. A public domain conceptual costing tool (LC3 model) was developed for this purpose. MWW_SF (lime softening and sand filtration) and MWW_NF were the most cost-effective treatment options among the Tertiary treatment alternatives considered because of the higher effluent quality with moderate infrastructure costs and the relatively low doses of conditioning chemicals required. Life cycle inventory (LCI) analysis along with integration of external costs of emissions with direct costs was performed to evaluate relative emissions to the environment and external costs associated with construction and operation of Tertiary treatment alternatives. Integrated LCI and LCC analysis indicated that three-tiered treatment alternatives such as MWW_NSF and MWW_NFG, with regular chemical addition for treatment and conditioning and/or regeneration, tend to increase the impact costs and in turn the overall costs of Tertiary treatment. River water supply and MWW_F alternatives with a single step of Tertiary treatment were associated with lower impact costs, but the contribution of impact costs to overall annual costs was higher than all other treatment alternatives. MWW_NF and MWW_SF alternatives exhibited moderate external impact costs with moderate infrastructure and chemical conditioner dosing, which makes them (especially MWW_NF) better treatment alternatives from the environmental sustainability perspective since they exhibited minimal contribution to environmental damage from emissions.« less
Darren J Dixon - One of the best experts on this subject based on the ideXlab platform.
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reverse polarity reductive functionalization of Tertiary amides via a dual iridium catalyzed hydrosilylation and single electron transfer strategy
ACS Catalysis, 2020Co-Authors: Tatiana Rogova, Pablo Gabriel, Stamatia Zavitsanou, Jamie A Leitch, Fernanda Duarte, Darren J DixonAbstract:A strategy for the mild generation of synthetically valuable α-amino radicals from robust Tertiary amide building blocks has been developed. By combining Vaska’s complex-catalyzed Tertiary amide re...
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Tertiary amine synthesis via reductive coupling of amides with grignard reagents
Chemical Science, 2017Co-Authors: Langui Xie, Darren J DixonAbstract:A new iridium catalyzed reductive coupling reaction of Grignard reagents and Tertiary amides affording functionalised Tertiary amine products via an efficient and technically-simple one-pot, two-stage experimental protocol, is reported. The reaction – which can be carried out on gram-scale using as little as 1 mol% Vaska's complex [IrCl(CO)(PPh3)2] and TMDS as the terminal reductant for the initial reductive activation step – tolerates a broad range of Tertiary amides from (hetero)aromatic to aliphatic (branched, unbranched and formyl) and a wide variety of alkyl (linear, branched), vinyl, alkynyl and (hetero)aryl Grignard reagents. The new methodology has been applied directly to bioactive molecule synthesis and the high chemoselectivity of the reductive coupling of amide has been exploited in late stage functionalization of drug molecules. This reductive functionalisation of Tertiary amides provides a new and practical solution to Tertiary amine synthesis.
Choonhong Tan - One of the best experts on this subject based on the ideXlab platform.
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graphene oxide and rose bengal oxidative c h functionalisation of Tertiary amines using visible light
Green Chemistry, 2011Co-Authors: Yuanhang Pan, Shuai Wang, Choon Wee Kee, Emilie Dubuisson, Yuanyong Yang, Kian Ping Loh, Choonhong TanAbstract:Visible light induced oxidative C–H functionalisation of Tertiary amines catalysed by the combination of graphene oxide and Rose Bengal was developed. This reaction avoids the use of stoichiometric amounts of peroxy compounds as terminal oxidants. This reaction is useful for tri-alkyl amines including chiral Tertiary amines. Both cyanide and trifluoromethyl nucleophiles were shown to participate in this reaction, providing α-cyano- and α-trifluoromethylated Tertiary amines.
Radisav D. Vidic - One of the best experts on this subject based on the ideXlab platform.
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corrosion management in power plant cooling systems using Tertiary treated municipal wastewater as makeup water
Corrosion Science, 2012Co-Authors: Mahbuboor Rahman Choudhury, Radisav D. Vidic, Mingkai Hsieh, David A DzombakAbstract:Abstract Additional Tertiary treatment of secondary-treated municipal wastewater (MWW) is necessary to reduce its scaling potential for use in power plant cooling systems. In this study corrosiveness of three Tertiary-treated municipal wastewaters (acidified MWW, MWW treated by nitrification–filtration, and MWW treated by nitrification–filtration and granular activated carbon adsorption) towards mild steel, copper, and cupronickel alloys was assessed. pH, ammonia, and organic matter were identified as important corrosion influencing parameter in Tertiary-treated municipal wastewater. Corrosiveness of wastewater towards metal alloys increased after Tertiary treatments. However, corrosion of mild steel and copper alloys was controlled within acceptable limits using the corrosion inhibitor tolyltriazole.
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Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management
2012Co-Authors: David A Dzombak, Radisav D. Vidic, Amy E. LandisAbstract:Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing Tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different Tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various Tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three Tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to bemore » significantly enhanced with Tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the Tertiary treated waters. For MWW_NF treated water, the removal of ammonia by nitrification helped to reduce the corrosivity and biocide demand. Also, the lower pH and alkalinity resulting from nitrification reduced the scaling to an acceptable level, without the addition of anti-scalant chemicals. Additional GAC adsorption treatment, MWW_NFG, yielded no net benefit. Removal of organic matter resulted in pitting corrosion in copper and cupronickel alloys. Negligible improvement was observed in scaling control and biofouling control. For all of the Tertiary treatments, biofouling control was achievable, and most effectively with pre-formed monochloramine (2-3 ppm) in comparison with NaOCl and ClO2. Life cycle cost (LCC) analyses were performed for the Tertiary treatment systems studied experimentally and for several other treatment options. A public domain conceptual costing tool (LC3 model) was developed for this purpose. MWW_SF (lime softening and sand filtration) and MWW_NF were the most cost-effective treatment options among the Tertiary treatment alternatives considered because of the higher effluent quality with moderate infrastructure costs and the relatively low doses of conditioning chemicals required. Life cycle inventory (LCI) analysis along with integration of external costs of emissions with direct costs was performed to evaluate relative emissions to the environment and external costs associated with construction and operation of Tertiary treatment alternatives. Integrated LCI and LCC analysis indicated that three-tiered treatment alternatives such as MWW_NSF and MWW_NFG, with regular chemical addition for treatment and conditioning and/or regeneration, tend to increase the impact costs and in turn the overall costs of Tertiary treatment. River water supply and MWW_F alternatives with a single step of Tertiary treatment were associated with lower impact costs, but the contribution of impact costs to overall annual costs was higher than all other treatment alternatives. MWW_NF and MWW_SF alternatives exhibited moderate external impact costs with moderate infrastructure and chemical conditioner dosing, which makes them (especially MWW_NF) better treatment alternatives from the environmental sustainability perspective since they exhibited minimal contribution to environmental damage from emissions.« less
Michael Tylla - One of the best experts on this subject based on the ideXlab platform.
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ultrafiltration as an advanced Tertiary treatment process for municipal wastewater
Desalination, 1998Co-Authors: George Tchobanoglous, Jeannie L Darby, Keith N Bourgeous, John Mcardle, Paul Genest, Michael TyllaAbstract:Abstract Treatment of secondary and Tertiary municipal wastewater by membrane filtration has been investigated at the University of California, Davis, California, USA, as described in the following paper. Secondary and Tertiary wastewater used during this investigation were produced from activated sludge and media filtration processes, respectively. Ultrafiltration, hollow-fiber, polysulfone membranes were used in this investigation for the treatment of secondary and Tertiary municipal wastewater. Membrane operating parameters investigated were cross-flow velocity, with circulation and single pass flow, trans-membrane pressure and backflushing methods. Total solids and particle size distribution of secondary and Tertiary wastewater were analyzed and correlated with observed membrane performance. Reduction of total solids, biological oxygen demand (BOD), and chemical oxygen demand (COD) of secondary wastewater was also determined after treatment with membrane and media filtration processes.
