Automated chlorine dosage in a simulated drinking water treatment plant: a real case study

In recent decades, increasing attention has been paid to the sustainability of products and processes, including activities aimed at environmental protection, site reclamation or treatment of contaminated ef¿uents, as well as the valorization of waste through the recovery of resources. Although implemented with ‘noble intentions’, these processes are often highly invasive, unsustain-able and socially unacceptable, as they involve signi¿cant use of chemical products or energy. This Special Issue is aimed at collecting research activities focused on the development of new processes to replace the above-cited obsolete practices. Taking inspiration from real problems and the need to face real cases of contamination or prevent potentially harmful situations, the development and opti-mization of ‘smart’ solutions, i.e., sustainable not only from an environmental point of view but also economically, are discussed in order to encourage as much as possible their actual implementation.Peer ReviewedPostprint (published version

A solution for robotized sampling in wastewater plants

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This work presents a solution to automatize the water sampling process of outdoor basins in a wastewater treatment plant. The system proposed is based on the utilization of collaborative robotics: a team of an UAV and a terrestrial robotic platform make a route along the plant collecting and storing the water samples. The architecture of the designed system is described in terms of functional blocks, and implementation details including software frameworks and hardware on the UAV are provided. As the objective of the system is industry levels of robustness and performance, the UAV use is minimized and subjected to control from the robotic ground platform, reducing risks associated with autonomous UAV. To conclude, results from experiments performed to validate the viability of the system and study several design decisions are presented and briefly discussed, including: estimation of the accuracy of several GNSS technologies on the plant, viability of the landing operation over a mobile robotic platform and controlling a quadrotor over waters.Peer ReviewedPostprint (author's final draft

Feed-forward control for a drinking water treatment plant chlorination process

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Chlorination in drinking water treatment plants (DWTP) is the final process applied to water before it is sent to storage tanks in the supply network for subsequent human consumption. An excessive dosage of chlorine or, conversely, too small a dosage, may breach existing legal regulations on mandatory limits. In DWTP where there is no significant variability in the quality of the water to be treated, a type of control that is proportional to the flow rate in the effluent can have fully satisfactory results. Therefore, Proportional-Integral (PI) control is a rather frequently used solution. However, when there are inherently long delays in the process, variability in the quality of the water to be treated and considerable variations alternative type is needed. This article presents the strategy and results of a control method that proposes a Fuzzy based feed-forward system to complement an existing PI control. The control system results are shown as applied to the DWTP of Barcelona city, producing satisfactory experimental results.Postprint (author's final draft

Contribución al modelado e implementación de un control avanzado para un proceso de cloración de una estación de tratamiento de agua potable

Tesis amb processos de protecció de dades i acord de confidencialitat aprovada per la comissió acadèmica del programa de doctorat; hom publica la versió xifrada.The effective disinfection in chlorination tanks of drinking water treatment plants depends on many factors that must be taken into account when designing a suitable control system. The chemical characteristics of the water to be treated, the possible flow disturbances or the contact time of the chlorine with the outgoing water must be taken into account in order to establish a control strategy that contemplates adaptation to the different possible scenarios. An excessive dosage of chlorine, or on the other hand a deficit in the dose, may lead to a legal failure to comply with the existing regulations that establish obligatory limit values. Likewise, an overdose generates an unnecessary expenditure of chlorine and, as a collateral effect, problems due to an increase in the maximum values allowed for by-products such as trihalomethanes. The contribution of the present work regarding chlorination in drinking water treatment tanks is divided into two areas: simulation and control. The studies and field work have been carried out on one of the largest drinking water treatment plants in southern Europe. The design and implementation of a simulator has made it possible to reproduce the behaviour of the system to test the proposed controller without the need to interfere in the production process, thus avoiding possible effects on the supply. The control implemented at the Plant is based on a control advance that compensates the disturbance of ammonium and other compounds and a feedback with planned gains depending on the flow rate and the temperature and origin of the water to be treated. The two control blocks (feedforward and feedback) are supervised by a diffuse system that, depending on the characteristics of the water to be treated, combines a control feedforward with a gains planning on a PI control.The simulation and experimental results obtained have been validated with real plant data from the Supervision System database. The control presented in this work has been integrated into the current Plant Control System. The results obtained, apart from being satisfactory, have allowed the Plant Control Room operator to move from the role of Process Control to that of Supervision of the Chlorination Process.La desinfección efectiva en depósitos de cloración de Estaciones de Tratamiento de Agua Potable, depende de numerosos factores que hay que tener en cuenta a la hora de diseñar un sistema de control adecuado. Las características químicas del agua a tratar, las posibles perturbaciones de caudal o el tiempo de contacto del cloro con el agua de salida se deberán tener en cuenta para establecer una estrategia de control que contemple la adaptación a los diferentes posibles escenarios. Una dosificación excesiva de cloro o por el contrario un déficit en la dosis, puede incurrir en un incumplimiento legal de la normativa existente que fija unos valores límites de obligado cumplimiento. Así mismo, una sobredosificación genera un gasto innecesario de cloro y de forma colateral problemas por un incremento en los valores máximos permitidos de subproductos como los trihalometanos. La contribución del presente trabajo respecto a la cloración en depósitos de tratamiento de agua potable se divide en dos ámbitos: la simulación y el control. Los estudios y trabajos en campo se han realizado sobre una Estación de Tratamiento de Agua Portable de las más grandes del sur de Europa. El diseño y la implementación de un simulador ha permitido reproducir el comportamiento del sistema para testear el controlador propuesto sin necesidad de interferir en el proceso productivo, evitando así posibles afectaciones en el suministro. El control que se ha implementado en la Planta está basado en un avance del control que compensa la perturbación del amonio y otros compuestos y una realimentación con ganancias planificadas en función del caudal , la temperatura y el origen del agua a tratar. Los dos bloques de control (avance y realimentación) son supervisados por un sistema difuso que, en función de las características del agua a tratar, combina un avance del control (feedforward) junto a una planificación de ganancias sobre un control PI. Los resultados de simulación y experimentales obtenidos han sido validados con datos reales de Planta a partir de la base de datos del Sistema de Supervisión. El control presentado en este trabajo ha sido integrado en el actual Sistema de Control de la Planta. Los resultados obtenidos además de ser satisfactorios han permitido al técnico de la Sala de Control de Planta pasar del rol de Control del Proceso, al de Supervisión del Proceso de Cloración.Postprint (published version

Diseño e implementación de una interfaz simulada para el estudio del control y supervisión de una estación depuradora de agua residual

En la optimización del funcionamiento de los procesos que intervienen en una estación depuradora de aguas residuales es importante aunar la sinergia entre estrategias de control automático, diseño ergonómico de centros de control e interfaces hombre-máquina, y cuidado del medio ambiente. Existen en el mercado herramientas de modelado y simulación que ofrecen al experto ayudas para el soporte a la decisión en este ámbito, una interfaz simulada de control y supervisión puede aportar también aspectos de creación de prototipos y diseños de nuevas estrategias de control de una forma rápida y eficaz, permitiendo incluir la valoración del experto en la mejora de los sistemas. El presente trabajo de máster ha consistido en el diseño de una interfaz simulada que permita evaluar los diferentes comportamientos de técnicos y responsables del telecontrol de Estaciones de Tratamiento de Agua. Dicho entorno tecnológico está destinado también a ser una herramienta de validación de nuevas interfaces que se deseen integrar en programas de supervisión y control en explotación. La arquitectura utilizada en el diseño e implementación de la interfaz de simulación está basada en un software de emulación en la plataforma ControlLogix de Rockwell Automation para la lógica de control del controlador (PLC), un software de supervisión y control (SCADA) Intouch de la firma WonderWare y la tecnología OPC/DDE como interfaz estándar de comunicaciones entre el PLC y el Scada

Automated chlorine dosage in a simulated drinking water treatment plant: a real case study

In this paper, we present a simulator of a drinking water treatment plant. The model of the plant was based in hydraulic and matter transportation models. In order to not introduce more inaccuracies in the simulation, the control system was based in the real equipment deployed in the plant. This fact was the challenging part of the simulator, and an accurate design is presented in this research, wherein the sampling time had to be limited to interchange data between the SCADA in the plant and the simulator in real time. Due to the impossibility to stop the plant when testing the new control strategy, a simulator implemented the plant behavior under different extreme conditions. The validation of the simulator was performed with real data obtained from the plant.Peer Reviewe

Design and implementation of a virtual sensor network for smart waste water monitoring

A high density virtual sensor network has been designed to robotize sampling tasks associated with monitoring of water treatment plant with open air basins. The designed virtual network is to be actually implemented by a network of autonomous UAV sensor platform, which was designed using a multi-agent system approach. Each UAV sensor platform can deploy a multiparametric sensor able to provide analyzed metrics in real-time, or a custom designed sample capture probe to be delivered to a laboratory through a special landing pad. This way, as the sensing hardware is deployed on-board UAVs, the system can analyze any point of the open air basins, operating as if an arbitrarily large amount of sensors or sampling points had been deployed through the installation. A general view of the implementation of the system is provided: in terms of hardware, the prototype platform built is described, with emphasis in the technical integration aspects; the software is mainly described in terms of the design principles used and how the chosen technologies support them to solve specific challenges. Evaluation of the components of the system built is performed independently: autonomous flight performance has been tested on-site; the accuracy of the localization technologies deemed as deployable options has been evaluated in controlled flights; and the viability of the sample capture device designed and built has been experimentally tested.This research has been funded by the Spanish Ministry of Science, with the project DPI2016-78957-RPeer ReviewedPostprint (published version

A study of the human-system interface complexity sources in wastewater treatment plants

In human-automation interaction it is necessary to define methods and tools to assess the human-system interface complexity. In a first assessment, the use of an evaluation questionnaire aiming at detecting complexity sources in the human supervisory control room tasks in wastewater treatment plants (WWTP) is presented in this paper. The first results show that the elicitation of complexity sources can be useful to improve the interaction between humans and safety-critical systems in the industrial domain.Peer ReviewedPostprint (author’s final draft

A solution for robotized sampling in wastewater plants

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This work presents a solution to automatize the water sampling process of outdoor basins in a wastewater treatment plant. The system proposed is based on the utilization of collaborative robotics: a team of an UAV and a terrestrial robotic platform make a route along the plant collecting and storing the water samples. The architecture of the designed system is described in terms of functional blocks, and implementation details including software frameworks and hardware on the UAV are provided. As the objective of the system is industry levels of robustness and performance, the UAV use is minimized and subjected to control from the robotic ground platform, reducing risks associated with autonomous UAV. To conclude, results from experiments performed to validate the viability of the system and study several design decisions are presented and briefly discussed, including: estimation of the accuracy of several GNSS technologies on the plant, viability of the landing operation over a mobile robotic platform and controlling a quadrotor over waters.Peer Reviewe