INVENT ensures energy efficiency in American wwtp´s
One of our leading products provides significant energy savings in hundreds of US wastewater treatment plants (wwtp). The HYPERCLASSIC®-Mixing and Aeration System is a unique hyperboloid system that provides excellent mixing and homogenization as well as high oxygen transfer efficiency. The design is fluid-mechanically optimized featuring a hyperboloid-shaped mixer-body that is installed close to the bottom of the tank and a drive mounted on top of the water level on a bridge or support structure. The energy efficiency of the HYPERCLASSIC®-Mixing and Aeration System is proven by various projects in the USA, such as Manchester or Silicon Valley.
wwtp Manchester
In 2015, the town of Manchester, Connecticut completed a comprehensive upgrade of its aging water pollution control facility. The plant owners developed a scenario that would include operating two parallel aeration trains of eight banks. However, with only two aeration trains, there was a concern it would be necessary to take down half of the aeration volume to conduct maintenance. To resolve this matter, a mixer aerator system was incorporated into the design. Finally, each of the 16 banks had a HYPERCLASSIC®-Mixing and Aeration System installed.
This provided numerous process benefits and operational flexibility, such as the reuse of old aerator platforms . Also, each of the 16 banks could be operated in either an anoxic or aerobic condition. Therefore, if one or two banks had to be taken down in an aeration tank, the rest of the tank could be operated in a cyclic aeration mode to maintain nitrogen removal. Additionally, since mixing and aeration were independent, it was not necessary to over-aerate specific zones to maintain the required mixing intensity. With the hyperboloid mixer providing the mixing energy, aerobic zones at the end of the process can be maintained at much lower aeration levels, while still meeting process needs for mixing and thus saving significant energy.
The plant staff was highly involved in the planning and design of the upgrade. Because of their knowledge of the facility, creative solutions were developed to reuse tankage for nitrogen removal with minimal structural improvements. The staff was also open to newer technologies, such as the aforementioned hyperboloid mixer-aerator system, which allowed creative solutions and maximized operating flexibility.
wwtp Silicon Valley
The activated sludge aeration system in the wwtp of Silicon Valley Clean Water (SVCW) had essentially remained unchanged in thirty-five years since the construction of the facility in the early 1980s. Consideration was given options, including upgrades to fine-bubble diffused air, improved turbine mixers and the HYPERCLASSIC®-Mixing and Aeration System. The costs of a complete upgrade to a fine-bubble diffused air system were much higher compared to an innovative mixer/aerator design. This process led the SVCW team toward deeper exploration of the INVENT mixing and aeration technology.
The evaluation of the HYPERCLASSIC®-Mixing and Aeration System provided several options with added advantages which could be pursued:
- Locating the air discharge level approximately 54” closer to the floor of the aeration basins provided additional oxygen transfer efficiency.
- Using the INVENT diffuser ring imparted smaller bubble distribution promoting improved oxygen transfer.
- Anticipating the mixing currents provided longer bubble travel time in the aeration basin column, further promoting oxygen transfer efficiency.
- Utilizing micro-vortices that radiate outward from the mixer body, scoured the basin floor to prevent heavy solids accumulation.
SCVW evaluated theoretical performance and actual performance to justify a deeper discharge point for air into the aeration basins. Review of the performance curves for the blowers indicated the deeper discharge depth would put the blowers at the upper end of their capability. This trial proved successful, which furthered the concept of the HYPERCLASSIC®-Mixing and Aeration System. Though operating at full speed, the installation of the system still represented a dramatic reduction in electricity consumption within the SVCW activated sludge process.
Both plants were able to complete these energy-savings aeration upgrade projects successfully by implementing the INVENT HYPERCLASSIC®-Mixing and Aeration Systems. Sometimes small bubbles can make the difference!
