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作者： Ramesh Saagi Lund University

学位级别：博士

The integrated urban wastewater system (UWS) consists of different sections that are interconnected. These include: i) catchment; ii) sewer network; iii) wastewater treatment plant (WWTP); and finally, iv) receiving water system. Traditionally, these sections are operated and evaluated individually. However, it is now well-established that all the sections of an UWS should be operated in a holistic manner in order to improve the receiving water quality. The thesis aims at developing an integrated model library that can be used to simulate the dynamics of flow rate and pollutant loads in all the sections of an UWS on a single simulation platform. It is further aimed at defining a hypothetical UWS using the model library, so that future users can use the pre-defined layout to study multiple control strategies and structural modifications. In order to facilitate an objective evaluation of the results, criteria for evaluating river water quality as well as the sewer network and WWTP performance are described. Firstly, the suitability of existing model libraries is assessed. The building blocks from the Dynamic Influent Pollutant Disturbance Scenario Generator (DIPDSG) are used as the starting point for the catchment and sewer network model library. Additional model blocks that are missing in the DIPDSG are developed. A modified version of the benchmark simulation model No. 2 (BSM2) is used to simulate the WWTP. model blocks for river water quality assessment are developed. Using the model library, a hypothetical UWS for an urban catchment with 80 000 population equivalents and an area of 540 hectares is described. The UWS layout is used to develop and evaluate different control strategies (local/integrated) and structural modifications. The case studies indicate that: i) the presented model library and the layout can be used to develop various control strategies and evaluate their impact on river water quality; and ii) improving the performance of an individual section

关键词： benchmark simulation model Integrated control strategies Integrated modelling River water quality

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Optimization of Aeration Diffuser System Design: A simulation Study

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JOURNAL OF ENVIRONMENTAL ENGINEERING 2023年第4期149卷 04023003-04023003页

作者： Bengtsson, Simon Arnell, Magnus Promiko AB Briggatan 16 S-23442 Lomma Sweden Lund Univ Dept Biomed Engn BME Div Ind Elect Engn & Automation IEA POB118 S-22100 Lund Sweden

The influence of aeration diffuser system design on electricity usage, effluent water quality, and life-cycle cost in biological wastewater treatment was investigated. A plant-wide model was implemented, and simulations were carried out with different process configurations and aeration systems. model-aided design of new aeration diffuser systems could significantly decrease electricity usage and life-cycle cost while at the same time avoiding negative effects on the treatment performance. The optimum distribution of diffuser systems in tanks in series was found to be influenced by process configuration, volumetric loading rate, temperature, and the internal recirculation flow rate. Compared with a conventional design approach, increasing the number of diffusers, up to a critical point, led to higher energy efficiency and lower life-cycle cost. This was despite an increasing limitation of the minimum airflow rate, leading to dissolved oxygen levels significantly exceeding control targets. Aeration systems optimized by simulations were found to, independently of process configuration, exhibit 20% lower electricity usage and 16%-18% lower life-cycle costs compared with systems designed based on a more conventional approach typically applied in practice.

关键词： Activated sludge Aeration efficiency Energy Diffuser system design benchmark simulation model

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Dynamic alpha factors: Prediction in time and evolution along reactors

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WATER RESEARCH 2022年 216卷 118339-118339页

作者： Bencsik, Daniel Takacs, Imre Rosso, Diego SARL Dynamita 2015 Route Aiglun F-06910 Sigale France Natl Univ Publ Serv 2 Ludovika Ter H-1083 Budapest Hungary Univ Calif Irvine Water Energy Nexus Ctr Irvine CA 92697 USA Univ Calif Irvine Civil & Environm Engn Dept Irvine CA 92697 USA

The performance of aeration - one of the most costly processes at water resource recovery facilities - is heavily impacted by actual wastewater characteristics which are commonly taken into account using the alpha factor (alpha). This factor varies depending on hydraulic and organic loading;such variance includes both time and spatial fluctuations. In standard design practice, it is often considered as a fixed number, or at best, a predefined time series. The objective of this paper is to propose a new method of predicting plantwide trends in the alpha factor through the use of process modelling which can accommodate diurnal and seasonal variations. The authors' concept takes into account the dependence of alpha on sludge retention time in the form of degradation kinetics, the effects of organic loading (influent filtered COD), the presence or absence of anoxic zones, diffuser depth, and the impact of high MLSS found in certain, e.g., MBR, technologies. The developed model was calibrated using data from numerous facilities, relying on off-gas measurements and tests in clean and process water. model validation was carried out against averaged alpha factor gradient data from one plant, and against diurnal air flow measurements from another. The benchmark simulation model 1 configuration was used to demonstrate the applicability of the proposed model - in estimation of blower energy consumption and peak air flow requirements - comparing it with constant and scheduled alpha factor-based approaches.

关键词： Alpha factor Dynamic modelling benchmark simulation model Aeration Wastewater

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A model-Based Approach to Study the Effect of Temperature in Plant-Wide Biological Wastewater Treatment Plants

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JOURNAL OF WATER CHEMISTRY AND TECHNOLOGY 2022年第3期44卷 182-190页

作者： Sheik, Abdul Gaffar Seepana, Murali Mohan Ambati, Seshagiri Rao Natl Inst Technol Dept Chem Engn Warangal 506004 Telangana India

The effect of temperature on phosphorous, nitrogen, organic matter removal, overall effluent quality, methane, and hydrogen production in an activated sludge system (ASS) is assessed in this research. For the plant-wide model of the ASS, benchmark simulation model (BSM2-P) with an ASS (ASM2d) is used and the temperature is selected between 10 to 35 degrees C covering different seasons. A steady-state simulation is carried out to evaluate the effluent compositions by changing kinetic parameters. A total of fourteen kinetic expressions for the maximum growth rate of heterotrophic biomass, autotrophic, phosphate accumulating organisms and their decay rates, oxygen saturation, hydrolysis, fermentation and oxygen mass transfer coefficients are also considered. Improved removal efficiency of NH, TN, TP, COD, and BOD5 is obtained at 17, 20, 10, 20, and 28 degrees C temperatures respectively. The average percentage of removal is obtained as 22.2, 9.7, 28, 1.7, and 86.4% respectively for NH, TN, TP, COD, and BOD5 which is higher when compared to the removal rate at 15 degrees C. Further, the anaerobic digestion model (ADM1) is also used with changing physico-chemical parameters which are functions of temperature. The corresponding physico-chemical parameters are analysed in the range of 25 to 55 degrees C. A total of seven physico-chemical kinetic expressions for the acid-base equilibrium gases are considered which includes Henry's law coefficient for carbon dioxide, methane, hydrogen, and partial pressure of water. At higher temperature (55 degrees C) the ADM1 showed improved production efficiency rates for carbon dioxide and hydrogen but at lower level (25 degrees C) it showed lower production efficiency rates. The average production rates of methane, hydrogen, and CO2 at 55 degrees C different by -0.01, 54.1, and 7.8% respectively when compared at temperature of 28 degrees C. This knowledge of varying temperature leads to the operator to handle biological treatment for wa

关键词： activated sludge system anaerobic digestion model benchmark simulation model physico-chemical parameter and Henry's law coefficient

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Forecasting wastewater flows and pollutant loads: A comparison of data-driven models within the urban water system framework

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JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2024年第5期12卷

作者： Giberti, Matteo Dereli, Recep Kaan Bahramian, Majid Flynn, Damian Casey, Eoin Univ Coll Dublin Sch Chem & Bioproc Engn Dublin Ireland Technol Univ Dublin Environm Sustainabil & Hlth Inst Dublin Ireland Univ Coll Dublin Sch Elect & Elect Engn Dublin Ireland

The ability to forecast key features of wastewater treatment plant (WWTP) influent, is emerging as an important tool to enable advanced WWTP operational strategies. Various data driven models have been reported in the scientific literature for WWTP influent forecast however, there has been no quantitative comparison of them against each other. The present study is the first to undertake this comparison utilising a high-frequency reference dataset generated from the Urban Water System model. Specifically, the performance of autoregressive models was compared against time-delay networks, nonlinear autoregressive networks and long shortterm memory networks. Time-delay networks were generally found to outperform the other tested methods, although the reliability of the generated forecasts decreases as the prediction horizon exceeds one hour. While longer prediction horizons would be desirable, there is a trade-off between model accuracy and overall optimisation of plant operation. This study also highlights the challenge of dealing with both concentration and flow variations suggesting the need for future research to analyse the separate impacts of flow and concentration variations on model performance.

关键词： Autoregressive models benchmark simulation model Forecasting Wastewater Neural network

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Investigating energy and operation flexibility of membrane bioreactors by using benchmark simulations

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DESALINATION AND WATER TREATMENT 2021年 211卷 456-462页

作者： Wu, Haolun Derel, Recep Kaan Casey, Eoin Univ Coll Dublin Sch Chem & Bioproc Engn Dublin 4 Ireland

Wastewater volumes are increasing globally as a result of increased population and industrial growth. This, together with increasingly stringent discharge limits, has resulted in a consequent rise in energy demand for wastewater treatment. Activated sludge process has been successfully used for more than a century with various configurations for the removal of organic carbon and nutrients. Compared to conventional activated sludge plants, membrane bioreactors (MBRs) offer a higher treatment efficiency, however, they are energy-intensive. The aim of this study is to investigate the operational and energy flexibility of MBRs by mathematical modeling. Based on a variable electricity price tariff, an appropriate optimization strategy can save 9%-41% of the energy cost without violating exiting discharge standards. The results of dynamic simulation revealed that, under variable energy price structures, hybrid MBRs can provide significant flexibility for reducing energy costs while maintaining satisfactory effluent quality.

关键词： Aeration control benchmark simulation model Conventional activated sludge Energy Membrane bioreactor Wastewater treatment

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Static calibration of wastewater treatment plant models: Investigating calibration processes and objective functions

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JOURNAL OF WATER PROCESS ENGINEERING 2023年 54卷

作者： Khajavian, Ali Pourmohamadi, Anahita Khatibi, Yaser Nazif, Sara Univ Tehran Coll Engn Sch Civil Engn Tehran Iran

Mathematical modeling provides a reliable tool for optimal management and operation of wastewater treatment plants (WWTPs). Accurate calibration is crucial for producing reliable results, and static calibration is a critical initial step for this purpose, ensuring enough accuracy and minimizing later difficulties. The two main areas to investigate in static calibration are the appropriate calibration process and objective function. This study proposes a three-stage methodology for static calibration of model parameters. Nine different calibration objective functions considering various target variables are investigated to evaluate how different objective functions can affect the calibration process accuracy. The proposed approach is applied in a real WWTP with a carousel oxidation ditch for secondary treatment. benchmark simulation model No.2 (BSM2) is modified to be used for oxidation ditch modeling. The calibration results show less than 3 % prediction error for COD, TN, and TSS, and 6.7 % mean overall error. The validation resulted in 22.5 %, 10.6 %, and 31.5 % MARE (Mean Absolute Relative Error) for effluent COD, TN, and, TSS, respectively, indicating successful calibration. Comparing different objective functions indicates that in static calibration, the objective functions that consider more targets usually yield more accurate results in a relatively acceptable time.

关键词： Static calibration benchmark simulation model Optimization Wastewater treatment plant Oxidation ditch Objective function

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Predicting wastewater treatment plant performance during aeration demand shifting with a dual-layer reaction settling model

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WATER SCIENCE AND TECHNOLOGY 2020年第7期81卷 1365-1374页

作者： Giberti, Matteo Dereli, Recep Kaan Flynn, Damian Casey, Eoin Univ Coll Dublin Sch Chem & Bioproc Engn Dublin Ireland Univ Coll Dublin Sch Elect & Elect Engn Dublin Ireland

Demand response (DR) programmes encourage energy end users to adjust their consumption according to energy availability and price. Municipal wastewater treatment plants are suitable candidates for the application of such programmes. Demand shedding through aeration control, subject to maintaining the plant operational limits, could have a large impact on the plant DR potential. Decreasing the aeration intensity may promote the settling of the particulate components present in the reactor mixed liquor. The scope of this study is thus to develop a mathematical model to describe this phenomenon. For this purpose, benchmark simulation model No.1 was extended by implementing a dual-layer settling model in one of the aerated tanks and combining it with biochemical reaction kinetic equations. The performance of this extended model was assessed in both steady-state and dynamic conditions, switching the aeration system off for 1 hour during each day of simulation. This model will have applications in the identification of potential benefits and issues related to DR events, as well as in the simulation of the plant operation where aerated tank settling is implemented.

关键词： activated sludge benchmark simulation model demand and response energy settling wastewater treatment plant

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Extending Wastewater Treatment Process models for Phosphorus Removal and Recovery: A Framework for Plant-Wide modelling of Phosphorus, Sulfur and Iron

Extending Wastewater Treatment Process Models for Phosphorus...

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作者： Kimberly Solon Lund University

学位级别：博士

As problems associated with shortage in resource supply arise, wastewater treatment plants turn to innovation to transform themselves into resource recovery facilities. Water groups worldwide recognize that wastewater treatment plants are no longer disposal facilities but rather sources of clean water, energy and nutrients. One of the most important resources that can be recovered from wastewater treatment plants is phosphorus. Mathematical modelling can be utilised to analyse various operational strategies to recover phosphorus from the wastewater. However, incorporating phosphorus transformation processes in plant-wide models is complex. Firstly, the tri-valence of phosphates suggests non-ideality, which requires the use of a physico- chemical model to account for this non-ideality. Secondly, phosphorus has strong interlinks with sulfur and iron, which necessitates inclusion of their transformations in biological and physico-chemical models. Lastly, consolidating these into a plant-wide model aimed at describing phosphorus removal and/or recovery requires interfacing, modifications to the plant layout, addition of recovery unit processes and development of new control and operational strategies. The research work presented in this thesis addresses the aforementioned challenges. A physico-chemical model is developed to take into account ion activity corrections, ion pairing effects, aqueous phase chemical equilibria, multiple mineral precipitation and gas stripping/adsorption. The model is then linked with standard approaches used in wastewater engineering, such as the Activated Sludge model Nos. 1, 2d and 3 (ASM1, 2d, 3) and the Anaerobic Digestion model No. 1 (ADM1). The extensions of the ASM2d and ADM1 with phosphorus, sulfur and iron-related conversions followed. And finally, the extended models and the physico-chemical model are consolidated into a plant-wide model provided by the benchmark simulation model No. 2. The resulting model is used for simulation-bas

关键词： benchmark simulation model Anaerobic Digestion model Activated Sludge model Physico-chemistry Phosphorus removal Nutrient recovery

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Modification of the activated sludge model for chemical dosage

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Frontiers of Environmental Science & Engineering 2015年第4期9卷 694-701页

作者： Shuai MA Siyu ZENG Xin DONG Jining CHEN Gustaf OLSSON State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Department of Industrial Electrical Engineering and Automation Lund University Lund SE-22100 Sweden

Full-scale experiments have been carried out to adapt the activated sludge model ASM2d to include the influence of metal dosage （Fe^3＋ and Al^3＋） for phosphorus removal. Phosphorus removal rates, nitrification rates, as well as pH and sludge settling performance, were evaluated as functions of the metal dosages. Furthermore, models relating certain parameters to the dosage of chemicals have been derived. Corresponding parameters in the ASM2d and the secondary settler models, included in the benchmark simulation model No 1 （BSM1）, have been modified to take the metal influence into consideration. Based on the effluent limits and penalty policy of China, an equivalent evaluation method was derived for the total cost assessment. A large number of 300-day steady-state and 14-day open-loop dynamic simulations were performed to demonstrate the difference in behavior between the original and the modified BSM1. The results show that 1） both in low and high mole concentrations, Fe^3＋ addition results in a higher phosphorus removal rate than Al^3＋; 2） the sludge settling velocity will increase due to the metal addition; 3） the respiration rate of the activated sludge is decreased more by the dosage of Al^3＋ than Fe^3＋; 4） the inhibition of Al^3＋ on the nitrification rate is stronger than that of Fe^3＋; 5） the total operating cost will reach the minimum point for smaller dosages of Fe^3＋, but always increase with Al^3＋ addition.

关键词： activated sludge model chemical precipitation benchmark simulation model phosphorus removal,respiratory rate sludge settling

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