Sewage Treatment Plants: Economic Evaluation of Innovative Technologies for Energy Efficiency aims to show how cost saving can be achieved in sewage treatment plants through implementation of novel, energy efficient technologies or modification of the conventional, energy demanding treatment facilities towards the concept of energy streamlining.
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Energy saving opportunities for wastewater facilities: A review
Energy saving opportunities for wastewater facilities: A review
Energy self-sufficiency as a feasible concept for wastewater treatment systems
Energy self-sufficiency as a feasible concept for wastewater treatment systems
Energy Recovery from Wastewater Treatment Plants in the United States: A Case Study of the Energy-Water Nexus
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.
United Utilities, Davyhulme WWTW, CHP Plant
At the Davyhulme wastewater treatment works (WWTW) in Greater Manchester, United Utilities is generating renewable energy from sewage gas that is created from sludge left behind after the treatment of wastewater. United Utilities spent £100 million on the programme that leaves the sludge behind to be used to power the site. At the site 90,000 tonnes of sludge is being processed a year. Clarke Energy has supplied 2 new GE’s Jenbacher JMS620 GS-BL gas engines and re-located 3 x JMS620 GS-BL existing engines to Davyhulme for this project, together creating 12.0MW of renewable power. This is the equivalent of powering over 10,000 typical UK homes.
Upgrading and methanisation projects at WWTP Avedøre
Enzymatic Biogas Upgrading
The techniques for removing CO2 from biogas are well known and available on the market in a number of ways to upgrade the biogas. Scrubbing with water or amine is most widely used methods. Common to all types is the large capital and operation cost (CAPEX & OPEX) in upgrading systems
A new technique is based on enzyme enhanced removal of the biogas’ content of CO2. The enzyme; Carbonic Anhydrase is well known as an accelerator for CO2 absorbtion and has been studied for decades. The enzyme is one of the fastest enzymes known in nature, and is present in all living organisms. Enzyme’s task is to transport CO2 in and out of the body tissue as lungs and muscles. The enzyme’s inability to remain active for longer periods in harsh industrial processes, has until now, prevented commercial use of the enzyme. Encapsulation of the enzyme in a gel has been tested in lab scale.
During spring 2015 Akermin and Ammongas will build a full-scale upgrading plant, that will handle the 3 million cubic meter biogas/year from WWTP Avedøre’s digesters.
The enzymes used in the project comes from Novozymes A/S,
In July 1, 2015 the biogas will be sent through the system and into the natural gas grid. The demonstration project will run until April 2017, and then will come a long period with commercial operation.
sludge2energy A way to energy self-sufficient sewage treatment plants
Co-incineration costs less, but on the other hand monoincineration provides the option of phosphorus recovery. Another factor in favour of incineration is the fact that it allows to recover the amount of energy consumed for sludge transport, dewatering and drying. It is an innovative concept of decentralised sludge utilisation by generation and use of thermal and electrical energy.The plant on WWTP Straubing is designed for 200,000 PE and presently treats about 35,000 m3 wastewater per day. After anaerobic sludge treatment and dewatering by means of centrifuges this is an annual volume of almost 9,000 t sludge dewatered to on average 28-29 % DR. The thermal energy content of dried sludge is a substantial value for the creation of an energy balance. The thermal value of dried sludge with 65% dry residue is comparable with brown coal and provides 1,020 kWh of energy. With according boiler efficiency, about 800 kWh of thermal energy can be generated. After deduction of further thermal losses in the micro gas turbine about 700 kWh of thermal energy effectively remain for the drying process. With a thermal energy consumption of about 565 kWh for the drying process there is even a surplus of energy available.
Use of biogas for cogeneration of heat and electricity for local application: performance evaluation of an engine power generator and a sludge thermal dryer
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.
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.