Instrumentation, Control And Automation Research Articles

Integrating online differential titrimetry and dynamic modelling as innovative energy saving strategy in a large industrial WWTP

Wastewater treatment plants (WWTP) are required to meet increasingly stringent effluent quality standards as well as to improve process sustainability in terms of energy efficiency, in line with the call for a paradigm shift towards the more sustainable concept of wastewater resource recovery facility (WRRF). In this context, optimised Instrumentation, Control and Automation (ICA) systems as well as process and plant-wide modelling have become key tools for optimising economic and environmental costs. The present work reports on the successfull integration of an innovative on-line continuous titrimeter and plant-wide modelling as a support tool for the optimisation of the nitritification unit in a large-scale industrial WWTP. The information gathered from the on-line titrimeter allowed for real-time estimation of the Ammonia Oxidation Rate of the activated sludge and, ultimately, of the nitrification residual capacity of the plant. Results on the titrimeter long-term operation and historical data modelling supported plant managing decisions, such as lowering the dissolved oxygen (DO) set-point of the oxidation unit, straightforwardly resulting in energy saving.Graphical abstract

Instrumentation, control and automation in wastewater – from London 1973 to Narbonne 2013

Key developments of instrumentation, control and automation (ICA) applications in wastewater systems during the past 40 years are highlighted in this paper. From the first ICA conference in 1973 through to today there has been a tremendous increase in the understanding of the processes, instrumentation, computer systems and control theory. However, many developments have not been addressed here, such as sewer control, drinking water treatment and water distribution control. It is hoped that this review can stimulate new attempts to more effectively apply control and automation in water systems in the coming years.

From a black-box to a glass-box system: the attempt towards a plant-wide automation concept for full-scale biogas plants

Biogas plants gain worldwide increasing importance due to several advantages. However, concerning the equipment most of the existing biogas plants are low-tech plants. E.g., from the point of view of instrumentation, control and automation (ICA) most plants are black-box systems. Consequently, practice shows that many biogas plants are operated sub-optimally and/or in critical (load) ranges. To solve these problems, some new biogas plants have been equipped with modern machines and ICA equipment. In this paper, the authors will show details and discuss operational results of a modern agricultural biogas plant and the resultant opportunities for the implementation of a plant-wide automation.

Automation Development in Water and Wastewater Systems

Advanced control is getting increasingly demanded in water and wastewater treatment systems. Various case studies have shown significant savings in operating costs, including energy costs, and remarkably short payback times. It has been demonstrated that instrumentation, control and automation (ICA) may increase the capacity of biological nutrient removing wastewater treatment plants by 10-30% today. With further understanding and exploitation of the mechanisms involved in biological nutrient removal the improvements due to ICA may reach another 20-50% of the total system investments within the next 10-20 years. Disturbances are the reason for control of any system. In a wastewater treatment system they are mostly related to the load variations, but many disturbances are created also within the plant. In water supply systems some of the major disturbances are related the customer demand as well as to leakages or bursts in the pipelines or the distribution networks. Hardly any system operates in steady state but is more or less in a transient state all the time. Water and energy are closely related. The role of energy in water and wastewater operations is discussed. With increasing energy costs and the threatening climate changes this issue will grow in importance.

Instrumentation, Control and Automation for full-scale Sequencing Batch Reactor Plants

The sequencing batch reactor (SBR) technology possesses a high process flexibility and treatment efficiency. Unfortunately, up to now most SBR plants are still using fixed time-based sequential control (TSC), which can not react flexibly. Therefore, this paper will focus on instrumentation, control and automation (ICA) for SBR plants, because with the help of modern supervisory control and data acquisition (SCADA) systems and dynamic RTC it is possible to operate SBR plants much more effectively.

Instrumentation, control and automation for full-scale manure-based biogas systems

In recent years manure-based biogas plants (MBBP) have won more and more importance, because of the numerous ecological advantages. The processes are similar to processes, which have been well known for many decades in anaerobic wastewater/sludge treatment. As a result of technical progress and permanently rising prices for non-renewable energy, MBBPs have become more and more economically reasonable. Because of the economies of scale law more and more larger MBBPs are being built (250-2000 kW(el)). With regard to investment costs, reactor volumes and complexity etc., these (centralized) plants are comparable with small wastewater treatment plants (WWTP). Consequently, as actually in the case of the small WWTPs a rising use of instrumentation, control and automation (ICA) for larger MBBPs can be observed.

Instrumentation, control and automation in the water industry – state-of-the-art and new challenges

Instrumentation, control and automation (ICA) are key technologies in modern water and wastewater systems. Ever present disturbances make it necessary to automatically attenuate their consequences. A wastewater treatment system is load driven, while a water distribution system is demand driven. Despite the variability the system outputs have to be satisfactory. Economic realities encourages the application of ICA to make a maximum use of plant capacities. An increasing complexity of competing processes in a modern nutrient removal plant makes more elaborate control necessary. The final goal of protecting the environmental resources necessitates an integrated view of several interdependent systems, the collection, transport and treatment processes. In this integrating development ICA will be a decisive technology.

Plant-wide control: dream, necessity or reality?

Instrumentation, control and automation (ICA) are key technologies in modern water and wastewater systems. Despite the variability of the influents the system outputs have to be satisfactory. Economic realities and new water directives encourage the application of ICA to make a maximum use of plant and other storage capacities. The final goal of protecting the environmental resources necessitates an integrated view of several interdependent systems, including the collection, transport and treatment processes. In this integrating development ICA will be a decisive technology.

Lessons learnt from 15 years of ICA in anaerobic digesters

Anaerobic digestion plants are highly efficient wastewater treatment processes with inherent energy production. Despite these advantages, many industries are still reluctant to use them because of their instability confronted with changes in operating conditions. There is therefore great potential for application of instrumentation, control and automation (ICA) in the field of anaerobic digestion. This paper will discuss the requirements (in terms of on-line sensors needed, modelling efforts and mathematical complexity) but also the advantages and drawbacks of different control strategies that have been applied to AD high rate processes over the last 15 years.

Benchmarking plant operation and instrumentation, control and automation in the wastewater industry

Benchmarking is an effective tool to compare the performance of full-scale wastewater treatment plant operation. In this study, 29 wastewater treatment plants from eight countries were surveyed with the aim of developing some key performance indicators, which may be used for benchmarking purposes. The level of utilisation of instrumentation, control and automation (ICA) has also been measured. The study of ICA utilisation revealed that on average only 23% of all sensors are used for online control. For most parameters, ICA is not the single dominant factor determining performance, although it is the factor that has the highest potential to improve performance. Eighty percent of the participating plants had implemented new control during the last five years leading to improvements in nitrogen and phosphorous removal, energy efficiency and ease of operation. The survey has quantified how “non-standardised” wastewater treatment plant operational practice is. Some simple key performance indicators are derived that relate the level of removal of ammonium, total nitrogen, phosphorous and suspended solids to the resources needed for their removal, i.e. volume, energy, organic matter and precipitation chemicals. Several indicators are suggested for each substance. The indicators show a great difference from the best to the poorest performance indicating that improvement potentials exist at many plants.

Status and future trends of ICA in wastewater treatment – a European perspective

The status of instrumentation, control and automation (ICA) within the European wastewater community is reviewed and some major incentives and bottlenecks are defined. Future trends of ICA are also discussed. The information is based on a COST 624 workshop and a non-exhaustive survey with regard to ICA carried out in 13 European countries during March 2001. The level of instrumentation (type of sensors, usage frequency, etc.) and how these instruments are used for on-line control purposes are presented for each individual country (Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Netherlands, Romania, Slovenia, Spain, Sweden and Switzerland). The most common types of applied real-time control in wastewater treatment plants are given. One conclusion of the paper is that sensors no longer represent the main bottleneck for on-line control, rather the lack of plant flexibility is more troublesome. Moreover, the current transitional phase of the wastewater industry in Europe represents a unique opportunity to apply ICA on a large scale. The driving forces are simply too strong to ignore.

Assesment of disinfection by‐products removal by ozonation coupled with adsorption

This research work was performed to evaluate ozonation and granular activated carbon adsorption processes from the view‐point of controlling the formation of disinfection by products (DBPs). Both the humic acid and raw water were first preozonated and then adsorbed on the activated carbon to assess the potency for removal of total organic carbon (TOC) and DBPs. The disinfection by‐product including THMs and HAAs, in principle, can be successfully removed through a use of the ozonation and granular activated carbon (GAC) adsorption processes. However, in practice dealing with the raw water, it is necessary to introduce the pilot‐plant to obtain the design and operation guidelines for the water treatment plant through the ICA (Instrumentation Control and Automation) program in our future research work.

Future Directions in Instrumentation, Control and Automation in the Water and Wastewater Industry

The need to optimize treatment plant performance and to meet increasingly stringent effluent criteria are two key factors affecting future development of instrumentation, control and automation (ICA) applications in the water and wastewater industry. Two case studies are presented which highlight the need for dynamic modelling and simulation software to assist operations staff in developing effective instrumentation control strategies, and to provide a training environment for the evaluation of such strategies. One of the limiting factors to date in realizing the potential benefits of ICA has been the inability to adequately interpret the large number of existing instrumentation inputs available at treatment facilities. The number of inputs can exceed the number of control loops by up to three orders of magnitude. The integration of dynamic modelling and expert system software is seen to facilitate the interpretation of real-time data, allowing both quantitative (instrumented) and qualitative (operator input) information to be integrated for process control. Improvements in sensor reliability and performance, and the development of biological monitoring sensors and control algorithms are also discussed.

Functional Approach Leads to Successful ICA across 124 Water and 389 Wastewater Treatment Works

Thames Water Utilities Limited operates a complex network of 124 water and 389 wastewater treatment works. Regulatory requirements are driving a massive capital programme of more than ₤2 Billion over 5 years to improve performance of these facilities. Improvements are planned, engineered, and operated by a variety of internal and external groups and individuals. Shareholders are demanding profitability and the Director General is pushing for improvements to customer service. To achieve its objectives, Thames has developed an instrumentation, control and automation (ICA) systems master plan. The plan is based on the utility s water and wastewater functional requirements. The functional approach is applied to the large number of diverse facilities by grouping facilities and processes into classifications. The approach is used throughout the plan. Each process and its associated process control strategy are clearly defined to ensure consistency and the cost-effective implementation of instrumentation and control across Thames. The functional approach was developed for each process control strategy using a series of structured workshops to achieve consensus and company-wide acceptance. Each department of the utility was involved in the workshops (including engineering, operations, maintenance, management systems, research and development, operational science). Top management sponsored the planning effort and committed to making the plan a reality.

ICA in the UK Water Industry: Highlights of Recent Developments in the Applications of Optical Techniques

The current situation in respect of the impact of recent legislation and funding mechanisms on progress with developments in instrumentation, control and automation (ICA) in the UK Water Industry is discussed, problems with progress identified and potential solutions discussed. Recent developments in applied optical sensing are detailed, particularly those involving the use of Raman Scattering and optical fluorescence utilising non-contact laser probes and detectors and fibre-optic based sensors for use in portable and permanent station monitors.

The Application of ICA in Sewage Treatment – Witney Evaluation and Demonstration Facility (EDF)

The Witney Sewage Treatment Works of Thames Water has been established as the Evaluation and Demonstration Facility (EDF) for instrumentation, control and automation (ICA) in sewage treatment. The objectives of the process related EDF programme have included demonstration of the viability of computer-based process management systems, the investigation of the interactions of processes and the development of methods for their optimisation. Evaluation of process monitoring instrumentation has demonstrated that whilst severe shortcomings still exist in some areas reliable process automation can be achieved. Successful routine operation of the Witney plant has been maintained by the automatic control system and a detailed assessment of the main control functions has shown benefits which include cost savings, more accurate control and early warning of equipment failure. Progress has also been made in the modelling both of process performance and of operating costs. This work will lead to the development of software tools to aid process management and to enable process optimisation.

On-Line Analytical Instrumentation in the Water Industry — Problems and Practical Solutions

Water industry needs in instrumentation and control have been discussed mainly against a background of developments in the UK, in Europe and the US, although requirements in developing areas, where different, have not been ignored. Limitations of existing instrumentation, control and automation (ICA) systems have been discussed, and so too have potential improvements resulting from recent developments in sensor and system technology including developments in microelectronics and microcomputers. Certain sensor and system developments of particular relevance have been discussed in more detail, and so too have certain organisational and logistical aspects. Finally, some new horizons have been explored.