Energy recovery from wastewater treatment plants via anaerobic digestion with biogas utilization and biosolids incineration with electricity generation. We estimate that anaerobic digestion could save 628 to 4,940 million kWh annually in the United States. In Texas, anaerobic digestion could save 40.2 to 460 million kWh annually and biosolids incineration could save 51.9 to 1,030 million kWh annually.
Resource Type: Literature
Evaluation of reflection and refraction in simulations of ultraviolet disinfection using the discrete ordinates radiation model.
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.
Frequency pressure regulation in water supply systems
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.
Detailed dynamic pumping energy models for optimization and control of wastewater applications
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.
MONTEIRO, M.A.G.; MONACHESI, M.G. Eficiência energética em sistemas de bombeamento. Rio de Janeiro, Eletrobras; Procel, 2005. 86 p. (Manual Prático)
MONTEIRO, M.A.G.; MONACHESI, M.G. Eficiência energética em sistemas de bombeamento. Rio de Janeiro, Eletrobras; Procel, 2005. 86 p. (Manual Prático)
Please note that this text is in Portuguese
Pump cavitation various npshr criteria, nphsa, margins, and impeller life expectancy
This tutorial deals with pump cavitation, discussing various net positive suction head required (NPSHR) criteria, net positive suction head available (NPSHA) margins and impeller life expectancy. It gives an introduction to the subject matter and provides insights on particulars like cavitation inception, 3 percent head drop, and 40,000 hours impeller life, as well as NPSH scaling laws. It further devotes attention to the effect of dissolved gases and thermal suppression (i.e., thermodynamic effect). With regard to numerical prediction capabilities the use of computational fluid dynamics (CFD) shall be discussed. Furthermore, guidance for cavitation damage diagnosis shall be given, including the peculiar aspects of various cavitation modes, the prediction of cavitation erosion rate, and assessment of impeller life expectancy. The tutorial will further address NPSHR criteria and NPSHA margin factors.
Calibration and optimization of the pumping and disinfection of a real water supply system
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.
Energy Efficiency in the Water Industry: A Compendium of Best Practices and Case Studies – Global Report
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.
Water and wastewater energy best practice guidebook
Water and wastewater energy best practice guidebook.
Micro-turbines on drinking water treatment plant in France (Super Rimiez)
Microturbines installed on drinking water supply network allow converting the hydraulic potential energy loss resulting from this hydraulic design into electrical energy. The drinking water treatment plant of SUPER RIMIEZ is located higher than the customers leading to an excess pressure (>17 bars) at domestic network inlets. Installation of 4 micro-turbines on drinking water supply network: 4.5 million kWh/y generated.