Use of supervisory, control, and data acquisition (SCADA) system for monitoring, supervision and controlling of pumping systems can help minimize energy consumption of GHG emissions. It includes measurements in real time of water levels, pressures, flows, energy consumption and other operational parameters. It also helps to adjust and control the pump station operation, contributing to fight water losses or infiltration, reduce pumping during energy peak hours and adjust pumping volumes to the needs of the system. The SCADA systems provide utility managers with access to real-time operating data and can help offset the higher operating costs by minimizing unplanned downtime and improving maintenance plans. The SCADA system can also be used to optimize pumping in real-time through advanced pump optimization software and control, or through either a model-based or knowledge-based optimization that is implemented via a rule-based system programmed into the SCADA system. This type of optimization entails the use of algorithms to determine the best pumping scheme for a given situation. This can incorporate the peak energy times previously referenced, but also a prioritization of which pumps or pumping stations are used to maximize efficiency whenever possible. For example, if only a certain volume is demanded, then the SCADA system will first operate the most efficient pumps or pumping stations to meet the demand until greater capacity or more pumps are needed.
This is the first professional’s guide to every aspect of pollution control for all types of water bodies. From at-the-source prevention to technical treatment solutions, the Water QualityControl Handbook brings readers expert guidance on assessing,controlling, eliminating, and remediating the many factors that contribute to water pollution.
A small unit of cogeneration of energy and heat was tested at the Centre for Research and Training on Sanitation UFMG/COPASA – CePTS, located at the Arrudas Sewage Treatment Plant, in Belo Horizonte, Minas Gerais, Brazil. The unit consisted of an engine power generator adapted to run on biogas, a thermal dryer prototype and other peripherals (compressor, biogas storage tank, air blower, etc.). The heat from engine power generator exhaust gases was directed towards the thermal dryer prototype to dry the sludge and disinfect it. The results showed that the experimental apparatus is self-sufficient in electricity, even producing a surplus, available for other uses. The tests of drying and disinfection of sludge lasted 7 h, leading to an increase in solids content from 4 to 8% (50% reduction in sludge volume). Although the drying of sludge was not possible (only thickening was achieved), the disinfection process proved very effective, enabling the complete inactivation of helminth eggs.
Simulations of UV disinfection systems require accurate models of UV radiation within the reactor. Processes such as reflection and refraction at surfaces within the reactor can impact the intensity of the simulated radiation field, which in turn impacts the simulated dose and performance of the UV reactor. This paper describes a detailed discrete ordinates radiation model and comparisons to a test that recorded the UV radiation distribution around a low pressure UV lamp in a water-filled chamber with a UV transmittance of 88%. The effects of reflection and refraction at the quartz sleeve were investigated, along with the impact of wall reflection from the interior surfaces of the chamber. Results showed that the inclusion of wall reflection improved matches between predicted and measured values of incident radiation throughout the chamber. The difference between simulations with and without reflection ranged from several percent near the lamp to nearly 40% further away from the lamp. Neglecting reflection and refraction at the quartz sleeve increased the simulated radiation near the lamp and reduced the simulated radiation further away from the lamp. However, the distribution and trends in the simulated radiation field both with and without the effects of reflection and refraction at the quartz sleeve were consistent with the measured data distributions.
In water supply systems, pressure management in most cases is proven to be the most cost-effective activity related to water loss control. As an advanced method of pressure control, it is possible to use variable frequency drives for centrifugal pump control. Pressure regulation can be performed with constant pressure or with proportional pressure control. The application of proportional pressure control is particularly applicable in water supply systems as the operating pump performance is constantly adapting the pressure to the actual demand. Along with lower leakage losses, it also results in lower energy consumption and the elimination of non-stationary phenomena, thereby extending the pump lifetime. Therefore, the paper presents a theoretical discussion of the proportional pressure control. Possible savings are shown on the numerical example of water supply system of the city of Velika Gorica.
A simple graphical tool was developed, that finds the optimal combination of pumps and their rotational speeds for all possible working points for a pump battery. The tool was integrated into EPANET as well as EPA SWMM simulation packages. The tool allows us to analyse and optimize operation non-identical parallel pumps with different minimum and maximum frequencies for all possible working points. Pump characteristics and efficiency curves can be given in tabular format or as analytical functions of flow. Degradation of pump efficiency at lower rotational speed is taken into account, as well as motor and variable speed drive efficiencies at partial loads. The optimal solution provided by the tool was compared to measurements in two case studies. Our case studies showed 6.1–8.5% reduction in energy usage using the optimal parallel pumping control strategy compared to the currently used strategy, where all running pumps have the same frequency
Despite the increasing level of detail in wastewater treatment process models, oversimplified energy consumption models (i.e. constant ‘average’ power consumption) are being used in optimization exercises. A new dynamic model for a more accurate prediction of pumping costs in wastewater treatment has been developed to overcome this unbalance in the coupled submodels. The model is calibrated using two case studies. The first case study concerns the centrifugal influent pumps (Nijhuis RW1-400 · 525A) of the municipal wastewater treatment plants (WWTPs) in Eindhoven (The Netherlands), governed by Waterboard De Dommel. For the second case study, concerning a centrifugal pump (Flygt, type NT3153 · 181) of the intermediate pumping station (pumping primary treated wastewater) of the Mekolalde WWTP, located in Bergara (Guipúzcoa, Spain), a model extension was necessary in order to allow a better description of the pump curve, making the model more generic. Both cases showed good agreement between the model predictions and the measured data of energy consumption. The model is thus far more accurate compared with other approaches to quantify energy consumption, paving the way towards ‘global’ process optimization and new, improved control strategies for energy reduction at WWTPs.
Maintaining a disinfectant residual in water distribution systems WDSs is generally considered paramount to ensuring a safe drinking water supply. This objective can be assisted by the use of booster stations to increase disinfectant concentrations throughout the network. However, identifying the appropriate dose at each station is an optimization problem. The aim is to minimize the total mass of disinfectant dosed and reduce the cost of disinfection along with potential taste, odor, or by-product problems, while maintaining a certain minimum residual in the network. The residual present in the water at any location is not only dependent on the amount of disinfectant added to the water, but also the hydraulics of the system and the resulting detention times. A number of previous studies have tackled this optimization problem, however, a review of current literature suggests that in many cases the hydraulics of the system have been held constant, or the WDSs considered were hypothetical systems with relatively few constraints. This study considers the booster disinfection dosing problem, including daily pump scheduling, for a real system in Sydney, Australia. Before the system can be optimized, a representative model is required to ensure useful results, and the many constraints on the daily operation system must be accounted for in the fitness function considered. The results from the optimization study indicate it is necessary to consider the hydraulics as well as the dosing regime in the optimization process, as cycling reservoir levels minimizes detention times, and hence, disinfectant residuals are maintained at the extremities of the network. Also, significant energy cost savings of up to 30% can be made by scheduling the pumping in the system in line with the off-peak electricity costs.
Over the last decade, energy consumption by the water sector has increased considerably as a consequence of the implementation of new technologies to meet new potable water and effluent quality standards. The price of energy has also substantially increased and these increases will be compounded by the need for additional energy intensive processes to achieve more exacting regulatory requirements.
This Compendium draws together the best practice in energy efficient design and operation of water industry assets. The book identifies the developments and future opportunities by detailed examination of current best practice and technologies:
It illustrates incremental improvements in energy efficiency through optimisation of existing assets and operations. More substantial improvements in energy efficiency from the adoption of novel technologies. Successful case studies based on results of full scale operations. This compendium is an invaluable reference for water engineers, utility managers, and water and energy professionals.
Performance Evaluation of the “Pump as Turbine” Based Micro Hydro Project in KINKO Village, Tanzania