Mark Rupke - Academia.edu (original) (raw)
Papers by Mark Rupke
Water Science and Technology, Jul 1, 1994
ABSTRACT In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical M... more ABSTRACT In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.
Water Science and Technology, 2001
In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling f... more In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; H...
Proceedings of the Water Environment Federation, 2002
Authors: Deborah Ross, MASc., P.Eng., KMK Consultants Limited* Troy Briggs, M.Eng., P.Eng., KMK C... more Authors: Deborah Ross, MASc., P.Eng., KMK Consultants Limited* Troy Briggs, M.Eng., P.Eng., KMK Consultants Limited David Bagley, Ph.D., P.Eng., University of Toronto Mark Rupke, P.Eng., City of Toronto ... *220 Advance Blvd., Brampton, Ontario, Canada L6T 4J5
Proceedings of the Water Environment Federation, 2004
ABSTRACT Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility with an opera... more ABSTRACT Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility with an operating capacity of 818,000 cubic metres per day. ABTP serves an estimated connected population of 1.25 million and is managed and operated by the Water Pollution Control Division of the Works and Emergency Services Department of the City of Toronto. ABTP is located on the shores of Lake Ontario. Over the year residents who live in the neighbouring community have complained of foul odours associated with the plant. Several odour abatement measures have been taken in the last three to four decades to combat the odour nuisance impact in the community. However these measures did not totally control the odou problem.In April 2001, the City of Toronto in consultation with the Neighborhood Liaison Committee (NLC) selected a firm that specializes in resolving odour impact issues. The objective was to conduct a plant-wide odour assessment in order to quantify the impact and to formulate recommendations to mitigate the odour nuisance problem.This paper describes the high level of involvement and active participation of the affected community during the conduct of the project from defining the scope of work to selection of consultants to convening regular monthly progress meetings and presentations to the community members and finally the detailed review and approval of the consultants' recommendations. The close and steady involvement of the representatives of the affected community throughout the project helped build a trusting relationship between the NLC, the City and the consultants. Over time a positive feeling was developed resulting in a truly cooperative approach to resolving what after all was a community problem. The positive rapport generated continued right through the detailed review and approval of the consultants' recommendations for impact reduction strategies. The paper also describes the procedure developed for responding to community odour complaints during the implementation phase of the recommended impact reduction measures over the next few years.This paper will be useful to utility managers, consultants and community groups who need to work together to solve an often difficult problem that can affect many peoples quality of life.
Proceedings of the Water Environment Federation, 2002
Six odorous volatile aromatic compounds (OVACs) were identified through GC-MS analysis of headspa... more Six odorous volatile aromatic compounds (OVACs) were identified through GC-MS analysis of headspace samples from stored biosolids, including toluene, ethylbenzene, styrene, pcresol, indole, and skatole. Based on the chemical structures of these OVACs and past research, they are likely to be the degradation products of protein, more specifically the aromatic amino acids tryptophan, tyrosine, and phenylalanine. The objectives of this research were to determine if the pathways for production of OVACs from protein or amino acid degradation existed in biosolids. If so, the results could be used to develop odor control strategies. Tryptophan addition was tested and an elevated concentration of indole was observed immediately after 1 day of storage. Unlike the immediate formation of indole, skatole appeared to have a lag-period before accumulation. This suggests the importance of available tryptophan in biosolids to indole and skatole production. In addition, p-cresol accumulated immediately after the addition of tyrosine. Phenylalanine, which was expected to be the precursor for toluene, ethylbenzene, and styrene formation, did not show any influence on their production except at day 1. Previous research indicated that methanogens are responsible for the degradation of VOSCs, and VOSCs accumulate when methanogens are inhibited. However, no apparent concentration change of OVACs was observed when 2-bromoethanesulfonic acid (BES) was incorporated into biosolids formethanogen inhibition. The observed OVAC profiles indicated a slow and low level production of OVACs, which lasted for at least six months during biosolids storage.With the low odor detection threshold of these six odorous compounds, they may be the major causes for the malodor in biosolids during long-term storage.
An experimental study that examined the elemental composition of waste activated sludge as it pro... more An experimental study that examined the elemental composition of waste activated sludge as it progressed through mesophilic and thermophilic anaerobic digestion was completed. It was found that the oxygen mass fraction of the VSS increased while the carbon content decreased as digestion progressed. Small differences were observed in the responses observed for mesophilic and thermophilic digestion with the former having a greater increase in oxygen content. With the exception of nitrogen, the average molecular composition of the VSS was found to be consistent with that previously reported for microbial cells. The COD/VSS ratio of the solids decreased as digestion progressed and varied from 1.6-1.2 g COD/g VSS. When employing fixed default values for the COD/VSS ratio, the BioWin model was able to adequately predict biogas production but the prediction of COD/VSS deviated from the observed values as digestion progressed.
A combination of experimental testing and modeling was employed to assess the biodegradable fract... more A combination of experimental testing and modeling was employed to assess the biodegradable fraction of primary and waste activated sludges generated by municipal wastewater treatment. Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges under anaerobic conditions. The results indicate that for primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described mathematically using a first order decay function with a decay coefficient of 0.0075 d-1. The results suggest that the extent of digestibility can be improved by enhancing the degradability of endogenous decay products.
The objective of this study was to identify methods for estimating the anaerobic digestibility of... more The objective of this study was to identify methods for estimating the anaerobic digestibility of waste activated sludges. Waste activated sludge streams were generated in three sequencing batch reactors treating screened municipal wastewater. The wastewater and waste activated sludge properties were initially determined through fitting of the Biowin process simulator to data that was collected during a 15 day intensive sampling event. Samples of the waste activated sludge streams from the SBR's were subsequently characterized through aerobic respirometry and batch anaerobic digestion. Respirometry proved to be an effective tool for characterizing the active heterotrophic fraction of waste activated sludges and could serve as a suitable technique for determining sludge composition for input to anaerobic models where reliable simulation of the wastewater treatment plant is not possible. Anaerobic digestion of the waste activated sludges revealed decreasing CH 4 production and correspondingly lower COD removals as the SRT of the sludge increased. The Biowin simulator was capable of accurately describing the digestion of the waste activated sludge samples for SRTs that are typically employed in practice. For extended digestion times (i.e. greater than 30 days) model simulations consistently underpredicted the extent of digestion. Incorporation of a first order decay mechanism for the endogenous decay products with a rate constant of 0.0075 d-1 into the model resulted in accurate simulations for all sludge SRTs.
Proceedings of the Water Environment Federation, 2007
The following paper is a comparison of an organic media biofilter and a synthetic media biofilter... more The following paper is a comparison of an organic media biofilter and a synthetic media biofilter 15 for the treatment of residual odors emanating from the operation of a biosolids dewatering and 16 truck loading system at the City of Toronto's Ashbridges Bay Treatment Plant. 17 18 The system compared was an in-ground, header/lateral system operated in a forced draft, up 19 flow, open top configuration. The biofilter system consists of a 72,000 m 3 /hr four cell arrangement, consisting of a pre-humidification system, supplementary moisture addition through a surface irrigation system and variable frequency controlled ventilation fans. The odor control system was constructed with a chemical scrubber system using sodium hypochlorite and sodium hydroxide, followed by the biofilter. Odor testing revealed that the biofilter was sufficient to treat the odors without pre-treatment from the scrubber system. The scrubber system was removed from operation, and the biofilter maintained its exceptional performance. The scrubbers have yet to be re-commissioned. Biosolids dewatering facilities are typically characterized by persistent residual nuisance odors that are composed of organics and reduced sulphur compounds such as dimethyl sulphide (DMS), dimethyl disulphide (DMDS), and methyl mercaptan (MM). These compounds, with low water solubility and high molecular weights are difficult to degrade biologically to meet stringent Ministry of the Environment (MOE) odor emission guidelines. This paper describes the dewatering process, the generation and characterization of odors, and compares the odor removal characteristics of softwood bark organic media against a mineral based, permanent inorganic media. Practical operating experiences are discussed in detail and performance under a variety of conditions is examined using theoretical models. These kinetic models are used to describe the degradation characteristics of the process and can be used to predict the performance of the systems under a variety of operating conditions.
Proceedings of the Water Environment Federation, 2002
The recent testing and commissioning of the odor control system for a new biosolids facility at T... more The recent testing and commissioning of the odor control system for a new biosolids facility at Toronto's Ashbridges Bay Treatment Plant demonstrated excellent control of organic sulfides through two-stage chemical scrubbing. Testing used bottled gas to spike the inlet air. Sampling of existing biosolids air exhaust streams showed that several organic sulfides were present in concentrations that would likely be the predominant control parameters. For example, using gas chromatograph/flame photometric detection (GC/FPD) analysis, dimethyl sulfide was detected in the existing sludge hopper's exhaust air at a peak concentration of 74 parts per million (ppm), dimethyl disulfide at 43 ppm, and methyl mercaptan at 6 ppm. There is limited historical data on organic sulfide control in packed-bed chemical scrubbers. Manufacturers are reluctant to guarantee performance or will quote nominal removal. Review of the literature determined that control of the most frequently detected organic sulfides (methyl mercaptan, dimethyl sulfide, dimethyl disulfide) between 50 and 80 percent was achievable with single-stage scrubbing. The Ashbridges Bay odor control system was designed and constructed with two-stage packed bed chemical scrubbing followed by biofiltration. Biofiltration was included for additional treatment of organic odors and to enable operation with reduced chemical consumption during the low-odor periods. The paper describes the design and performance testing of the chemical scrubber system. The paper also discusses the synergy of using chemical scrubbers and biofilters in series.
Water Science & Technology, 2008
Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a... more Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges. For primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described with a first order decay function with a coefficient of 0.0075 d−1. For continuous flow digesters operating at SRTs of 30–60 days, the predicted VSS destruction with the modified model was approximately 10% higher than that predicted on the basis of inert endogenous deca...
Proceedings of the Water Environment Federation, 2000
The City of Toronto Main Treatment Plant currently treats an average of 670 ML/d, and produces ar... more The City of Toronto Main Treatment Plant currently treats an average of 670 ML/d, and produces around 50,000 dry tonnes per year of digested sludge cake at 25 to 30 percent dryness. Until 1996, all sludge was incinerated in multiple-hearth incinerators. Since 1996, up to 17,000 dry tonnes per year of the biosolids cake has been directly applied to agricultural land by Terratec on a 5 year pilot project, as part of a process eventually leading to 100 percent biosolids beneficial use. The City's plans for biosolids use were accelerated when in January 1998, the City Council directed staff to shutdown the incinerators by January 1, 1999 and introduce a beneficial use program. After a series of staff reports, Council accepted a delayed implementation plan, which would see the 100 percent beneficial use program introduced by January 1, 2001. PROGRAM MANAGEMENT To manage the transition to beneficial use, Council established a multi-level process: Biosolids Multi-Stakeholder Committee (BMSC) The BMSC has approximately 30 members, and reports to the City Works & Utilities Committee. Members include City Councilors, local business (Toronto Harbour) representatives, representatives from the four City treatment plant neighbourhood liaison committees, a watershed group, and MTP union members. This committee oversees the project and guides the process.
Proceedings of the Water Environment Federation, 2004
Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility managed and operated b... more Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility managed and operated by the City of Toronto. Several odor abatement measures have been taken over the last four decades to combat odor nuisance impacts in the community but these measures did not completely achieve the desired result. Odor complaints from neighboring residents continue to be a concern for the City of Toronto.
Proceedings of the Water Environment Federation, 2004
Water Science and Technology, Jul 1, 1994
ABSTRACT In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical M... more ABSTRACT In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.
Water Science and Technology, 2001
In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling f... more In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; H...
Proceedings of the Water Environment Federation, 2002
Authors: Deborah Ross, MASc., P.Eng., KMK Consultants Limited* Troy Briggs, M.Eng., P.Eng., KMK C... more Authors: Deborah Ross, MASc., P.Eng., KMK Consultants Limited* Troy Briggs, M.Eng., P.Eng., KMK Consultants Limited David Bagley, Ph.D., P.Eng., University of Toronto Mark Rupke, P.Eng., City of Toronto ... *220 Advance Blvd., Brampton, Ontario, Canada L6T 4J5
Proceedings of the Water Environment Federation, 2004
ABSTRACT Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility with an opera... more ABSTRACT Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility with an operating capacity of 818,000 cubic metres per day. ABTP serves an estimated connected population of 1.25 million and is managed and operated by the Water Pollution Control Division of the Works and Emergency Services Department of the City of Toronto. ABTP is located on the shores of Lake Ontario. Over the year residents who live in the neighbouring community have complained of foul odours associated with the plant. Several odour abatement measures have been taken in the last three to four decades to combat the odour nuisance impact in the community. However these measures did not totally control the odou problem.In April 2001, the City of Toronto in consultation with the Neighborhood Liaison Committee (NLC) selected a firm that specializes in resolving odour impact issues. The objective was to conduct a plant-wide odour assessment in order to quantify the impact and to formulate recommendations to mitigate the odour nuisance problem.This paper describes the high level of involvement and active participation of the affected community during the conduct of the project from defining the scope of work to selection of consultants to convening regular monthly progress meetings and presentations to the community members and finally the detailed review and approval of the consultants' recommendations. The close and steady involvement of the representatives of the affected community throughout the project helped build a trusting relationship between the NLC, the City and the consultants. Over time a positive feeling was developed resulting in a truly cooperative approach to resolving what after all was a community problem. The positive rapport generated continued right through the detailed review and approval of the consultants' recommendations for impact reduction strategies. The paper also describes the procedure developed for responding to community odour complaints during the implementation phase of the recommended impact reduction measures over the next few years.This paper will be useful to utility managers, consultants and community groups who need to work together to solve an often difficult problem that can affect many peoples quality of life.
Proceedings of the Water Environment Federation, 2002
Six odorous volatile aromatic compounds (OVACs) were identified through GC-MS analysis of headspa... more Six odorous volatile aromatic compounds (OVACs) were identified through GC-MS analysis of headspace samples from stored biosolids, including toluene, ethylbenzene, styrene, pcresol, indole, and skatole. Based on the chemical structures of these OVACs and past research, they are likely to be the degradation products of protein, more specifically the aromatic amino acids tryptophan, tyrosine, and phenylalanine. The objectives of this research were to determine if the pathways for production of OVACs from protein or amino acid degradation existed in biosolids. If so, the results could be used to develop odor control strategies. Tryptophan addition was tested and an elevated concentration of indole was observed immediately after 1 day of storage. Unlike the immediate formation of indole, skatole appeared to have a lag-period before accumulation. This suggests the importance of available tryptophan in biosolids to indole and skatole production. In addition, p-cresol accumulated immediately after the addition of tyrosine. Phenylalanine, which was expected to be the precursor for toluene, ethylbenzene, and styrene formation, did not show any influence on their production except at day 1. Previous research indicated that methanogens are responsible for the degradation of VOSCs, and VOSCs accumulate when methanogens are inhibited. However, no apparent concentration change of OVACs was observed when 2-bromoethanesulfonic acid (BES) was incorporated into biosolids formethanogen inhibition. The observed OVAC profiles indicated a slow and low level production of OVACs, which lasted for at least six months during biosolids storage.With the low odor detection threshold of these six odorous compounds, they may be the major causes for the malodor in biosolids during long-term storage.
An experimental study that examined the elemental composition of waste activated sludge as it pro... more An experimental study that examined the elemental composition of waste activated sludge as it progressed through mesophilic and thermophilic anaerobic digestion was completed. It was found that the oxygen mass fraction of the VSS increased while the carbon content decreased as digestion progressed. Small differences were observed in the responses observed for mesophilic and thermophilic digestion with the former having a greater increase in oxygen content. With the exception of nitrogen, the average molecular composition of the VSS was found to be consistent with that previously reported for microbial cells. The COD/VSS ratio of the solids decreased as digestion progressed and varied from 1.6-1.2 g COD/g VSS. When employing fixed default values for the COD/VSS ratio, the BioWin model was able to adequately predict biogas production but the prediction of COD/VSS deviated from the observed values as digestion progressed.
A combination of experimental testing and modeling was employed to assess the biodegradable fract... more A combination of experimental testing and modeling was employed to assess the biodegradable fraction of primary and waste activated sludges generated by municipal wastewater treatment. Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges under anaerobic conditions. The results indicate that for primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described mathematically using a first order decay function with a decay coefficient of 0.0075 d-1. The results suggest that the extent of digestibility can be improved by enhancing the degradability of endogenous decay products.
The objective of this study was to identify methods for estimating the anaerobic digestibility of... more The objective of this study was to identify methods for estimating the anaerobic digestibility of waste activated sludges. Waste activated sludge streams were generated in three sequencing batch reactors treating screened municipal wastewater. The wastewater and waste activated sludge properties were initially determined through fitting of the Biowin process simulator to data that was collected during a 15 day intensive sampling event. Samples of the waste activated sludge streams from the SBR's were subsequently characterized through aerobic respirometry and batch anaerobic digestion. Respirometry proved to be an effective tool for characterizing the active heterotrophic fraction of waste activated sludges and could serve as a suitable technique for determining sludge composition for input to anaerobic models where reliable simulation of the wastewater treatment plant is not possible. Anaerobic digestion of the waste activated sludges revealed decreasing CH 4 production and correspondingly lower COD removals as the SRT of the sludge increased. The Biowin simulator was capable of accurately describing the digestion of the waste activated sludge samples for SRTs that are typically employed in practice. For extended digestion times (i.e. greater than 30 days) model simulations consistently underpredicted the extent of digestion. Incorporation of a first order decay mechanism for the endogenous decay products with a rate constant of 0.0075 d-1 into the model resulted in accurate simulations for all sludge SRTs.
Proceedings of the Water Environment Federation, 2007
The following paper is a comparison of an organic media biofilter and a synthetic media biofilter... more The following paper is a comparison of an organic media biofilter and a synthetic media biofilter 15 for the treatment of residual odors emanating from the operation of a biosolids dewatering and 16 truck loading system at the City of Toronto's Ashbridges Bay Treatment Plant. 17 18 The system compared was an in-ground, header/lateral system operated in a forced draft, up 19 flow, open top configuration. The biofilter system consists of a 72,000 m 3 /hr four cell arrangement, consisting of a pre-humidification system, supplementary moisture addition through a surface irrigation system and variable frequency controlled ventilation fans. The odor control system was constructed with a chemical scrubber system using sodium hypochlorite and sodium hydroxide, followed by the biofilter. Odor testing revealed that the biofilter was sufficient to treat the odors without pre-treatment from the scrubber system. The scrubber system was removed from operation, and the biofilter maintained its exceptional performance. The scrubbers have yet to be re-commissioned. Biosolids dewatering facilities are typically characterized by persistent residual nuisance odors that are composed of organics and reduced sulphur compounds such as dimethyl sulphide (DMS), dimethyl disulphide (DMDS), and methyl mercaptan (MM). These compounds, with low water solubility and high molecular weights are difficult to degrade biologically to meet stringent Ministry of the Environment (MOE) odor emission guidelines. This paper describes the dewatering process, the generation and characterization of odors, and compares the odor removal characteristics of softwood bark organic media against a mineral based, permanent inorganic media. Practical operating experiences are discussed in detail and performance under a variety of conditions is examined using theoretical models. These kinetic models are used to describe the degradation characteristics of the process and can be used to predict the performance of the systems under a variety of operating conditions.
Proceedings of the Water Environment Federation, 2002
The recent testing and commissioning of the odor control system for a new biosolids facility at T... more The recent testing and commissioning of the odor control system for a new biosolids facility at Toronto's Ashbridges Bay Treatment Plant demonstrated excellent control of organic sulfides through two-stage chemical scrubbing. Testing used bottled gas to spike the inlet air. Sampling of existing biosolids air exhaust streams showed that several organic sulfides were present in concentrations that would likely be the predominant control parameters. For example, using gas chromatograph/flame photometric detection (GC/FPD) analysis, dimethyl sulfide was detected in the existing sludge hopper's exhaust air at a peak concentration of 74 parts per million (ppm), dimethyl disulfide at 43 ppm, and methyl mercaptan at 6 ppm. There is limited historical data on organic sulfide control in packed-bed chemical scrubbers. Manufacturers are reluctant to guarantee performance or will quote nominal removal. Review of the literature determined that control of the most frequently detected organic sulfides (methyl mercaptan, dimethyl sulfide, dimethyl disulfide) between 50 and 80 percent was achievable with single-stage scrubbing. The Ashbridges Bay odor control system was designed and constructed with two-stage packed bed chemical scrubbing followed by biofiltration. Biofiltration was included for additional treatment of organic odors and to enable operation with reduced chemical consumption during the low-odor periods. The paper describes the design and performance testing of the chemical scrubber system. The paper also discusses the synergy of using chemical scrubbers and biofilters in series.
Water Science & Technology, 2008
Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a... more Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges. For primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described with a first order decay function with a coefficient of 0.0075 d−1. For continuous flow digesters operating at SRTs of 30–60 days, the predicted VSS destruction with the modified model was approximately 10% higher than that predicted on the basis of inert endogenous deca...
Proceedings of the Water Environment Federation, 2000
The City of Toronto Main Treatment Plant currently treats an average of 670 ML/d, and produces ar... more The City of Toronto Main Treatment Plant currently treats an average of 670 ML/d, and produces around 50,000 dry tonnes per year of digested sludge cake at 25 to 30 percent dryness. Until 1996, all sludge was incinerated in multiple-hearth incinerators. Since 1996, up to 17,000 dry tonnes per year of the biosolids cake has been directly applied to agricultural land by Terratec on a 5 year pilot project, as part of a process eventually leading to 100 percent biosolids beneficial use. The City's plans for biosolids use were accelerated when in January 1998, the City Council directed staff to shutdown the incinerators by January 1, 1999 and introduce a beneficial use program. After a series of staff reports, Council accepted a delayed implementation plan, which would see the 100 percent beneficial use program introduced by January 1, 2001. PROGRAM MANAGEMENT To manage the transition to beneficial use, Council established a multi-level process: Biosolids Multi-Stakeholder Committee (BMSC) The BMSC has approximately 30 members, and reports to the City Works & Utilities Committee. Members include City Councilors, local business (Toronto Harbour) representatives, representatives from the four City treatment plant neighbourhood liaison committees, a watershed group, and MTP union members. This committee oversees the project and guides the process.
Proceedings of the Water Environment Federation, 2004
Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility managed and operated b... more Ashbridges Bay Treatment Plant (ABTP) is a large sewage treatment facility managed and operated by the City of Toronto. Several odor abatement measures have been taken over the last four decades to combat odor nuisance impacts in the community but these measures did not completely achieve the desired result. Odor complaints from neighboring residents continue to be a concern for the City of Toronto.
Proceedings of the Water Environment Federation, 2004