Browsing by Author "Ulanicki, Bogumil"
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Item Metadata only Analysis of district metered areas (DMAs) performance(A.A. Balkema, 2003-01-01) Ulanicki, Bogumil; Prescott, Simon L.; Shipley, N.Item Open Access ASM1-based activated sludge model with biopolymer kinetics for integrated simulation of membrane bioreactors for wastewater treatment(Elsevier, 2015-09-01) Janus, Tomasz; Ulanicki, BogumilThis paper presents an activated sludge model suitable for modelling membrane bioreactors (MBRs) for wastewater treatment. The model, later referred to as combined EPS and SMP production ASM1-based model (CES-ASM1), extends Activated Sludge Model No. 1 (ASM1) with biokinetics of two types of bacterial biopolymers: soluble microbial products (SMP) and extracellular polymeric substances (EPS). The biopolymer kinetics in CES-ASM1 are, in their majority, borrowed from Laspidou and Rittmann[1] although, as shall be explained in the article, with one conceptual correction a kinetic pathway of biomass associated products (BAP). CES-ASM1 was calibrated on published experimental results from batch and continuous flow laboratory and pilot plant experiments and proved to be in good agreement with measurements. Standard set of parameters was then proposed as a combination of empirically identified and literature values. The model was then used to predict SMP and EPS production in an activated sludge system under various operating conditions.Item Open Access Battle of Postdisaster Response and Restoration(ASCE, 2020-06-10) Paez, Diego; Filion, Yves; Quintiliani, Claudia; Santopietro, Simone; Sweetapple, Chris; Meng, Fanlin; Farmani, Raziyeh; Fu, Guangtao; Butler, David; Zhang, Qingzhou; Zheng, Feifei; Diao, Kegong; Ulanicki, Bogumil; Huang, Yuan; Deuerlein, Jochen; Gilbert, Denis; Abraham, Edo; Piller, Olivier; Bałut, Alicja; Brodziak, Rafał; Bylka, Jędrzej; Zakrzewski, Przemysław; Li, Yuanzhe; Gao, Jinliang; Jian, Cai; Ou, Chenhao; Hu, Shiyuan; Sophocleous, Sophocles; Nikoloudi, Eirini; Mahmoud, Herman; Woodward, Kevin; Romano, Michele; Santonastaso, Giovanni Francesco; Creaco, Enrico; Di Nardo, Armando; Di Natale, Michele; Bibok, Attila; Salcedo, Camilo; Aguilar, Andrés; Cuero, Paula; González, Sebastián; Muñoz, Sergio; Pérez, Jorge; Posada, Alejandra; Robles, Juliana; Vargas, Kevin; Franchini, Marco; Galelli, Stefano; Kim, Joong Hoon; Iglesias-Rey, Pedro; Kapelan, Zoran; Saldarriaga, Juan; Savic, Dragan; Walski, ThomasThe paper presents the results of the Battle of Post-Disaster Response and Restoration (BPDRR), presented in a special session at the 1st International WDSA/CCWI Joint Conference, held in Kingston, Ontario, in July 2018. The BPDRR problem focused on how to respond and restore water service after the occurrence of five earthquake scenarios that cause structural damage in a water distribution system. Participants were required to propose a prioritization schedule to fix the damages of each scenario while following restrictions on visibility/non visibility of damages. Each team/approach was evaluated against six performance criteria that included: 1) Time without supply for hospital/firefighting, 2) Rapidity of recovery, 3) Resilience loss, 4) Average time of no user service, 5) Number of users without service for 8 consecutive hours, and 6) Water loss. Three main types of approaches were identified from the submissions: 1) General purpose metaheuristic algorithms, 2) Greedy algorithms, and 3) Ranking-based prioritizations. All three approaches showed potential to solve the challenge efficiently. The results of the participants showed that, for this network, the impact of a large-diameter pipe failure on the network is more significant than several smaller pipes failures. The location of isolation valves and the size of hydraulic segments influenced the resilience of the system during emergencies. On average, the interruptions to water supply (hospitals and firefighting) varied considerably between solutions and emergency scenarios, highlighting the importance of private water storage for emergencies. The effects of damages and repair work were more noticeable during the peak demand periods (morning and noontime) than during the low-flow periods; and tank storage helped to preserve functionality of the network in the first few hours after a simulated event.Item Metadata only A Behavioural Membrane Fouling Model for Integrated Simulation of Membrane Bioreactors for Wastewater Treatment(Elsevier, 2015-09-01) Janus, Tomasz; Ulanicki, BogumilThis paper presents a simple membrane fouling model intended for use in conjunction with an activated sludge model to form an integrated model of a membrane bioreactor (MBR). It is based on an earlier development of Liang et al.[1] who divided fouling into short-term reversible fouling tantamount with cake deposition and long-term irreversible fouling representing th effects of irreversible particle deposition inside membrane pores. The original model was extended to account for cake detachment, back- flushing, and dependency of soluble microbial products (SMP) deposition on permeate flux. The model was identified on two sets of data from two experiments: a short-term flux stepping experiment under fluxes higher from the ‘threshold flux’ and a long-term filtration experiment under fluxes not exceeding the ‘threshold flux’. Additionally, the paper proposes a simple ‘pen and ruler’ identification method for unique estimation of model parameters based on the information obtained from flux stepping experiments.Item Open Access Burst Detection in Water Distribution Systems via Active Identification Procedure(Exeter University, 2011-09-05) Skworcow, P.; Ulanicki, BogumilThis paper considers an approach to detect unreported pipe bursts in water distribution systems via active identification procedure. The approach involves carrying out an e-FAVOR test; results of the test are used together with a hydraulic model of the network as the inputs to a software tool, which is under development. New bursts indicators are proposed, which are considered to be more resilient to modelling errors and to inaccurate reading of the pressure logger elevation. The methodology was tested in practice in a manual manner and proved to be effective, but time consuming. In this paper some automatic analysis algorithms, developed to speed up the burst detection process, are described and tested via simulations. Results to date indicate suitability of the proposed burst indicators and the developed algorithms.Item Unknown Bursts Identification in Water Distribution Systems(ASCE, 2009-05-17) Borovik, Irina; Ulanicki, Bogumil; Skworcow, P.The leakage reduction problem as a whole is complex and requires co-ordinated actions in different areas of water network management, such as: direct detection and repair of existing bursts, general pipe rehabilitation programmes and operational pressure control. Water companies undertake a mixture of these complimentary actions. General pipe rehabilitation is the most costly and long term action, but is undertaken to improve a number of different factors including leakage and water quality. Operational pressure control is a cost-effective action for reducing leakage over whole sub-networks, and for reducing the risk of further leaks by smoothing pressure variations and is the subject of ongoing research. Detection and repair actions are targeted at sub-networks where bursts are present. Benefits of quick burst repair include reduced water losses, reduced disruption to traffic, reduced consequent losses (e.g. from flooding), and also reduced disruption to customers' supplies, which is an important water industry performance measure. The existing methods typically use passive identification approach whilst the presented approach is based on the active identification procedure. The proposed burst location algorithm is based on comparing data by means of statistical analysis from a simple field experiment with results of water network simulation. An extended network hydraulic simulator is used to model pressure dependent leakage terms. The presence of a burst changes the flow pattern and also pressure at network nodes, which may be used to estimate the burst size and its location. The influence of such random factors as demand flows and background leakage on the process of burst detection is also considered. The field experiment is an extended fixed and variable orifice (e-FAVOR) test. During this test inlet pressure is being stepped up and down and the following variables are measured: inlet flow, inlet pressure (head) and pressure at a number of selected sensitive nodes. The method consists of three stages and uses two different models; one is inlet flow model (IFM) to represent the total inlet flow and another is the extended hydraulic model to simulate different burst locations. Initially the presence of a potential burst is investigated. If this is confirmed values of the demand, background leakage flow and burst flow in IFM are subsequently estimated. These are used to identify the burst site at the third stage of the method. The approach has been validated by solving a practical case study with correct diagnosis of the existing problems.Item Open Access Combined Energy and Pressure Management in Water Distribution Systems(ASCE, 2009-05-17) Skworcow, P.; AbdelMeguid, Hossam Saadeldin; Ulanicki, Bogumil; Bounds, Peter; Patel, RidwanIn this paper a method is proposed for combined energy and pressure management via integration and coordination of pump scheduling with pressure control aspects. The proposed solution involves: formulation of an optimisation problem with the cost function being the total cost of water treatment and pumps energy usage, utilisation of an hydraulic model of the network with pressure dependent leakage, and inclusion of a PRV model with the PRV set-points included as a set of decision variables. Such problem formulation led to the optimizer attempting to reduce both energy usage and leakage. The developed algorithm has been integrated into a modelling, simulation and optimisation environment called FINESSE. The case study selected is a major water supply network, being part of Yorkshire Water Services, with a total average demand of 400 l/s.Item Metadata only Developing scenarios for future utility provision(2012) Ulanicki, Bogumil; Strzelecka, A.; Skworcow, P.; Janus, T.Item Metadata only Development and validation of a multi-configurable fouling model(2008-09-29) Tomasz, Janus; Paul, Parneet; Ulanicki, BogumilItem Metadata only Dynamic modeling of pressure reducing valves(American Society of Civil Engineers, 2003-01-01) Prescott, Simon L.; Ulanicki, BogumilModels are currently available for representing the dynamical behavior of most water network components. Such models are relatively simple, accurate and can be easily solved. However, there is no generally accepted dynamic model of a pressure reducing valve (PRV). The key contributions of this paper are the development of several dynamic models—two phenomenological, one behavioral, and one linear—to represent the behavior of PRVs. The models vary in complexity but perform similarly. Experimental data is used to assess the accuracy of the models. The phenomenological models are derived from physical laws and provide an excellent but complex representation of a PRV. The behavioral model is simpler and sufficient for most practical purposes. The linear model does not take the needle valve setting (which controls the valve's speed) into account and therefore has limited use.Item Metadata only Dynamic optimization approach for solving an optimal scheduling problem in water distribution systems(ASCE, 2007-01-01) Ulanicki, Bogumil; Kahler, Jens; See, H.A new dynamic optimization (DO) approach to solve large scale optimal scheduling problems for water distribution networks is presented. The main motivation of this research is to formulate an algorithm which is significantly faster than existing approaches. Optimal scheduling is a complex task as it includes the extended period hydraulic model represented by differential algebraic equations and mixed-integer decision variables. Obtaining a strictly optimal solution involves excessive computational effort; however, a near optimal solution can be found at significantly reduced effort using a simple heuristic assumption. The proposed method progresses in two stages—initially a relaxed continuous problem is solved and in the second stage, a mixed-integer solution is found which tracks the optimal reservoir trajectories by time decomposition and application of a local branch and bound method. This paper describes the first stage of the method. The state and algebraic variables are numerically resolved using a hydraulic simulator and the reduced gradients are calculated using adjoint equations. A comparative analysis is made of the results obtained from the DO formulation and also from a traditional nonlinear programming method on a benchmark water supply scheme, thus showing the numerical efficiency of the new approach.Item Open Access Effects of Sampling on Stability and Performance of Electronically Controlled Pressure-Reducing Valves(American Society of Civil Engineers, 2021-01-13) Janus, Tomasz; Ulanicki, BogumilThis paper explains and demonstrates how increasing a sampling period in pressure control may worsen a system’s performance and lead to instability. The notion of stability of continuous-time and discrete-time systems is briefly introduced and applied to a simple closed-loop inertial system. It is then demonstrated how the stability of dynamic systems depends on a sampling period as well as on gain. Subsequently, the analysis is applied to a model of an electronically controlled pressure-reducing valve (PRV) coupled with a transient model of a water distribution network (WDN). The occurrence of instabilities at overly long sampling periods is demonstrated. Practical recommendations on the appropriate choice of sampling times are put forth based on simulation results and control engineering rules of thumb given the closed-loop system’s dynamics. Performance of a theoretical pressure control scheme is then simulated under time-varying demands and with controllers designed to work at different sampling frequencies.Item Metadata only Efficient energy management of a large-scale water supply system(Taylor & Francis, 2006-09-01) Bounds, Peter; Kahler, Jens; Ulanicki, BogumilEfficient energy management is important for water companies in order to meet economic and environmental targets. For many water supply systems, increased savings can only be accomplished by taking into account the non-linear characteristics of the system in terms of both heads and flows and mixed-integer decision variables. Scheduling must be achieved with complicated tariffs that are frequently changed throughout the year, as well as changes to the network structure. The article shows a case study for energy management of a large-scale network using the computer-aided water network engineering software called FINESSE. The network is a typical large-scale supply network supplying many towns and cities. The model of the network includes 4388 pipes, 35 pumps, 63 variable control valves, 10 non-return valves and 16 variable head reservoirs. The study resulted in a set of mixed-integer optimal schedules that achieved a 14% saving in electrical energy while satisfying operating constraints.Item Open Access Energy and Utilities Infrastructure: Can All be in One?(2011-09) Camci, Fatih; Ulanicki, Bogumil; Boxall, J. B.; Chitchyan, R.; Varga, LizIn today‘s developed society it is fully expected that every household is provided with general utility products such as heating, lighting, water supply, communication, and waste removal. Provision of these utility products requires large and complex physical, economic and social structures that interact and are interdependent. Furthermore, we underline that each distinct utility product (communication, transportation, water, etc.) provided to our households incurs similar material and embodied energy expenses. But are such structures and their respective expenses really necessary? Or could energy (and other resources) be saved by reducing redundant utility infrastructures, while still maintaining services to the households? Conventional approaches to improved utility provision focus on better management models with optimization, enhanced handling, and increased efficiency in organisations. This paper, on the other hand, presents a novel and radical idea to address this complex problem, by moving from the management level to the scientific & technological level. The paper challenges the need for distinct utility infrastructures for household utility products provision. In particular, the paper discusses the emerging scientific and technological options for using a single energy-provision infrastructure, which would potentially deliver the full set of household utility services.Item Embargo A fast and practical method for model reduction of large scale water distribution networks(ASCE, 2014-04-01) Martinez Alzamora, F.; Salomons, E.; Ulanicki, BogumilThis paper presents a method for the reduction of network models described by a system of nonlinear algebraic equations. Such models are, for example, present when modeling water networks, electrical networks, and gas networks. The approach calculates a network model equivalent to the original one, but containing fewer components. This procedure has an advantage compared with straightforward linearization because the reduced nonlinear model preserves the nonlinearity of the original model and approximates the original model in a wide range of operating conditions. The method is applicable to hydraulic analysis and has been validated by simplifying many practical water network models for optimization studies. DOI: 10.1061/(ASCE)WR.1943- 452.0000333. © 2014 American Society of Civil Engineers.Item Metadata only Feedback rules for operation of pumps in a water supply system considering electricity tariffs(ASCE, 2012) AbdelMeguid, Hossam Saadeldin; Ulanicki, BogumilItem Metadata only Flow modulated dynamic pressure control with Aguai-Mod controller(CRC Press/Balkema, 2009-09-01) Li, Ping; Postlethwaite, Ian; Prempain, Emmanuel; Ulanicki, BogumilA number of control algorithms are described from a control perspective. Based on this, the newly invented Aqaui-Mod controller is presented and its dynamic performance for flow-modulated pressure control is assessed via simulation-based case studies.Item Open Access Fractality in water distribution networks(figshare, 2017-09-01) Diao, Kegong; Butler, David; Ulanicki, BogumilFractals have been identified as a common feature of many natural and artificial systems that exhibit similar patterning at different scales. Understanding fractals is a critical aspect of decoding complex systems, as the pattern of such large systems can be revealed by identifying only a small part of the system. Furthermore, identify existing features of such systems can start at the large scale with the fewest details of the system under scrutiny before doing a more detailed analysis at finer scales. Such a process provides an efficient and reliable way of analysing and managing information of big data systems. This study revealed the fractality in water distribution networks (WDNs) based on research on fractals in complex networks. Specifically, we explored the existence of fractal patterns in six real world WDNs of different complexities (e.g. from a network with only 21 pipes to a network with 2465 pipes). The box-covering algorithm has been applied, which is the most widely used method to distinguish between fractal or non-fractal networks. The WDNs are first mapped into undirected graphs. Next, the method partitions the nodes into boxes of size lB, i.e. the maximal distance between nodes within each box is at most lB-1. By varying the box sizes, different minimum numbers of boxes NB required to cover the entire network can be identified. A network is fractal if the regression line for log(NB) and log(lB) is linear. The results demonstrate the existence of fractal patterns in all case study WDNs, as linear regression lines with coefficient of determination over 0.95 (R^2>0.95) are obtained in all analyses. As further verification, the self-similarity on multiscales is revealed, i.e. the similarity in patterns of component criticality. Based on the fractal patterns, a systematic method is also developed for more efficient identification of critical pipes in WDNs, e.g. reducing the computational load by 61% in the case study.Item Open Access Fractality in Water Distribution Networks: Application to Criticality Analysis and Optimal Rehabilitation(Taylor and Francis, 2021-07-08) Diao, Kegong; Butler, David; Ulanicki, BogumilFractals have been identified as a common feature in many natural and artificial networks that exhibit self-similarity of the topological patterns, i.e. different parts of the system have similar structures to each other as well as to the whole system. This study investigates the fractality in water distribution networks (WDNs) and the application of the fractal property in WDNs analysis. Specifically, we explore the existence of fractal topological patterns in eight real-world WDNs of different complexities by using the box-covering algorithm. The results demonstrate all of the studied WDNs are fractal. Moreover, the application of the fractal property is demonstrated via critical pipe identification and optimal rehabilitation of benchmark real-world WDNs. All results show that the fractal-based approach can achieve better or equally good solutions compared with conventional methods in a much more efficient way, e.g. via automation of some processes or significant reduction in the search space/components to consider.Item Open Access Hydraulic modelling for pressure reducing valve controller design addressing disturbance rejection and stability properties(Elsevier, 2017-05-09) Janus, Tomasz; Ulanicki, BogumilPressure reducing valves (PRVs) are widely used in water distribution systems to reduce excess pressure caused by variations in terrain elevation or by excessive pumping. The fundamental role of a PRV is to maintain a desired outlet pressure irrespectively of hydraulic conditions in the water distribution network (WDN). Unfortunately, even a stable PRV can exhibit poor disturbance rejection resulting in variations of outlet pressure around the setpoint due to randomly varying demands. The aim of this paper is to better understand this phenomenon and to develop models which would facilitate designing effective controllers considering the stability and disturbance rejection issues
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