... 1136 J. Dudley The comparison between measured and predicted masstransfer coefficients is ...... more ... 1136 J. Dudley The comparison between measured and predicted masstransfer coefficients is ... JH (1984) Correction factors for the dynamic measurement of the volumetric mass transfercoefficient. ... APPENDIX A The calculation procedure adopted was, given the air flowrate: I ...
The development of ASM2 has created a complex model for biological phosphorus removal. Most of th... more The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.
Journal of Water Supply: Research and Technology—AQUA, 2008
The EU-funded project, TECHNEAU, is intended (among other tasks) to develop a new water treatment... more The EU-funded project, TECHNEAU, is intended (among other tasks) to develop a new water treatment simulator, in part to implement new process models to be developed within TECHNEAU. Before beginning any software development there has been a review of existing water treatment simulators, to identify what would be needed for a new system. This review has identified that there has been little usage of water treatment modelling, with the two main objections being the quantity of data required to calibrate the models, and the fragility of the models when applied outside the calibration region.
The conventional way to estimate the performance of an operational aerator is onerous. The proces... more The conventional way to estimate the performance of an operational aerator is onerous. The process involves isolating the aerator from incoming flow; switching the aerator off briefly to allow the dissolved oxygen levels to fall; restarting the aerator; and, monitoring the rate of dissolved oxygen increase to then estimate the mass transfer rate of the aerator, and from that the aeration efficiency. A Kalman filter is a technique for estimating the aerator performance in-situ, without the need for isolating the tank or changing operational settings. The filter provides estimates of the respiration rate and oxygen transfer rate. If there are additional power measurements then the aeration efficiency can also be estimated. The technique was evaluated at four wastewater treatment plants, with the results compared against conventional reaeration tests. The direct measurement of bubble sizes provides additional information on performance that the filter approach can miss. A new measuring...
The common view of chemical phosphorus removal is an equilibrium reaction between phosphate and i... more The common view of chemical phosphorus removal is an equilibrium reaction between phosphate and iron or aluminium, resulting in the precipitation of a metal phosphate complex. A comprehensive model based on this was developed by Jenkins and Hermanowicz (1993). This view has been replaced by an alternative interpretation (surface complexation modelling), where the dominant mechanism at typical wastewater pH values is the precipitation of iron or aluminium hydroxide, with subsequent phosphate adsorption onto the hydroxide surface (Takács et al., 2006, 2011; Smith et al., 2008a, 2008b, 2011; Szabó et al. 2008) and has been accorded the status of the current best understanding of chemical phosphorus removal (WERF, 2008; WEF, 2008). The Smith model has been extended to include the effects of alkalinity and sulphide on precipitation, competition for hydroxide surface by COD, the inclusion of temperature sensitivity, and the inclusion of pH as a calculated output. WRc, supported by UK wate...
EXTENDED ABSTRACT Catchment-level modelling has been regarded, since at least the middle 1980s, a... more EXTENDED ABSTRACT Catchment-level modelling has been regarded, since at least the middle 1980s, as a necessary part of providing integrated solutions for improving water quality in receiving waters. However, the tools that have been available to support this level of modelling have not made such modelling convenient. Typically there has been no support for data exchange between different vendors, and different classes of model (e.g., rivers, sewers and sewage works) have used different water quality parameters in their assessment. The purpose of the OpenMI has been to provide a first level of greater ease of data exchange between different programs, by removing the barrier of exchanging data between different programs. The OpenMI has also provided mechanisms to simplify exchanging quantities between different programs – for example, should one program expect flow in US units, and another in cumecs, simple transformations can be defined to ensure that each program can convert the dat...
This paper describes a numerical procedure for estimating differential mass and energy profiles a... more This paper describes a numerical procedure for estimating differential mass and energy profiles along a combustion tube. The technique solves the governing differential equations using a simple finite-difference procedure. The predicted combustion front location shows good agreement with that estimated from experimental temperature profiles.
Water science and technology : a journal of the International Association on Water Pollution Research, 2002
The development of ASM2 has created a complex model for biological phosphorus removal. Most of th... more The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.
... 1136 J. Dudley The comparison between measured and predicted masstransfer coefficients is ...... more ... 1136 J. Dudley The comparison between measured and predicted masstransfer coefficients is ... JH (1984) Correction factors for the dynamic measurement of the volumetric mass transfercoefficient. ... APPENDIX A The calculation procedure adopted was, given the air flowrate: I ...
The development of ASM2 has created a complex model for biological phosphorus removal. Most of th... more The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.
Journal of Water Supply: Research and Technology—AQUA, 2008
The EU-funded project, TECHNEAU, is intended (among other tasks) to develop a new water treatment... more The EU-funded project, TECHNEAU, is intended (among other tasks) to develop a new water treatment simulator, in part to implement new process models to be developed within TECHNEAU. Before beginning any software development there has been a review of existing water treatment simulators, to identify what would be needed for a new system. This review has identified that there has been little usage of water treatment modelling, with the two main objections being the quantity of data required to calibrate the models, and the fragility of the models when applied outside the calibration region.
The conventional way to estimate the performance of an operational aerator is onerous. The proces... more The conventional way to estimate the performance of an operational aerator is onerous. The process involves isolating the aerator from incoming flow; switching the aerator off briefly to allow the dissolved oxygen levels to fall; restarting the aerator; and, monitoring the rate of dissolved oxygen increase to then estimate the mass transfer rate of the aerator, and from that the aeration efficiency. A Kalman filter is a technique for estimating the aerator performance in-situ, without the need for isolating the tank or changing operational settings. The filter provides estimates of the respiration rate and oxygen transfer rate. If there are additional power measurements then the aeration efficiency can also be estimated. The technique was evaluated at four wastewater treatment plants, with the results compared against conventional reaeration tests. The direct measurement of bubble sizes provides additional information on performance that the filter approach can miss. A new measuring...
The common view of chemical phosphorus removal is an equilibrium reaction between phosphate and i... more The common view of chemical phosphorus removal is an equilibrium reaction between phosphate and iron or aluminium, resulting in the precipitation of a metal phosphate complex. A comprehensive model based on this was developed by Jenkins and Hermanowicz (1993). This view has been replaced by an alternative interpretation (surface complexation modelling), where the dominant mechanism at typical wastewater pH values is the precipitation of iron or aluminium hydroxide, with subsequent phosphate adsorption onto the hydroxide surface (Takács et al., 2006, 2011; Smith et al., 2008a, 2008b, 2011; Szabó et al. 2008) and has been accorded the status of the current best understanding of chemical phosphorus removal (WERF, 2008; WEF, 2008). The Smith model has been extended to include the effects of alkalinity and sulphide on precipitation, competition for hydroxide surface by COD, the inclusion of temperature sensitivity, and the inclusion of pH as a calculated output. WRc, supported by UK wate...
EXTENDED ABSTRACT Catchment-level modelling has been regarded, since at least the middle 1980s, a... more EXTENDED ABSTRACT Catchment-level modelling has been regarded, since at least the middle 1980s, as a necessary part of providing integrated solutions for improving water quality in receiving waters. However, the tools that have been available to support this level of modelling have not made such modelling convenient. Typically there has been no support for data exchange between different vendors, and different classes of model (e.g., rivers, sewers and sewage works) have used different water quality parameters in their assessment. The purpose of the OpenMI has been to provide a first level of greater ease of data exchange between different programs, by removing the barrier of exchanging data between different programs. The OpenMI has also provided mechanisms to simplify exchanging quantities between different programs – for example, should one program expect flow in US units, and another in cumecs, simple transformations can be defined to ensure that each program can convert the dat...
This paper describes a numerical procedure for estimating differential mass and energy profiles a... more This paper describes a numerical procedure for estimating differential mass and energy profiles along a combustion tube. The technique solves the governing differential equations using a simple finite-difference procedure. The predicted combustion front location shows good agreement with that estimated from experimental temperature profiles.
Water science and technology : a journal of the International Association on Water Pollution Research, 2002
The development of ASM2 has created a complex model for biological phosphorus removal. Most of th... more The development of ASM2 has created a complex model for biological phosphorus removal. Most of the published work on calibrating this model has focused on the design of experiments to maximise information with which to calibrate the model, or the use of hourly data collected around and within an aeration tank. But many sewage works do not collect such data, nor have such instrumentation. The application of ASM2 with sparse data collected at a low frequency, and mostly only input-output, is considered in this paper, based on data collected at a Swedish sewage works. This paper shows that ASM2 can be calibrated with such measurements. This paper also looks at a modification to ASM2d to better handle heterotrophic usage of volatile fatty acids, and the use of this model to study the effects of large increases in in-sewer storage on sewage treatment works. Concern about the generation of large quantities of VFAs, and their effect on the sewage treatment processes, was unfounded.
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Papers by Jeremy Dudley