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Big Sky, Montana, has upgraded its wastewater treatment plant to accommodate the growing volume of wastewater resulting from population growth and expanded sewer system connections. A Membrane Bioreactor (MBR) system was chosen as the optimal solution, supported by INVENT’s innovative mixing and aeration technologies. These technologies ensure efficient biological treatment and enable the reuse of treated water for golf course irrigation and snowmaking even under extreme climatic conditions.

Over recent years, the City of Big Sky has experienced significant population growth. In addition, a strategic initiative to connect more households to the municipal sewer system and reduce reliance on septic tanks has doubled the volume of wastewater treated over the past three decades.

To meet this increased demand, engineers from AE2S in Bozeman, Montana, were tasked with designing a major upgrade and expansion of the existing Big Sky Wastewater Treatment Plant (WWTP). After a thorough evaluation, a Membrane Bioreactor (MBR) system was selected for its ability to produce high-quality effluent. This treated water will be stored in local reservoirs for beneficial reuse, including irrigating golf courses in the summer and supporting snowmaking in the winter.

A key advantage of MBR systems is their ability to operate with high sludge concentrations for effective biological treatment. In such systems, reliable and energy-efficient mixing in anaerobic and anoxic zones is essential. To meet these requirements, INVENT Environmental Technologies was selected to provide advanced mixing solutions for the new biological reactors and fermenters. Working closely with AE2S engineers, INVENT proposed the HYPERCLASSIC^®-Mixer Evolution7 as the ideal solution.

The hyperboloid mixer design delivers highly efficient solids suspension and homogeneous mixing – critical for processes such as enhanced biological phosphorus removal and denitrification. The HYPERCLASSIC^® system’s unique shape, low rotational speed, and radial flow pattern ensure thorough bottom cleaning and prevent sedimentation. To ensure reliable operation in Montana’s harsh winter conditions, special cold-weather adaptations were made to the gearbox.

Beyond the biological reactors, the equalization tank presented a unique dual-function challenge: it required both mixing and intermittent aeration. Conventional aeration systems were unsuitable due to the tank’s irregular operating pattern. INVENT addressed this by installing the HYPERCLASSIC^®-Mixing and Aeration System, which integrates mechanical mixing with intermittent air dispersion.

As this marks the first installation of the HYPERCLASSIC^®-Mixing and Aeration System in Montana, a Standard Oxygen Transfer Rate (SOTR) test was conducted at INVENT’s headquarters in Erlangen, Germany. The full-scale clean water test, performed at design water depths, validated the system’s oxygen transfer efficiency. A comprehensive test report was submitted to AE2S and the City of Big Sky and received full approval.

The successful implementation of INVENT’s mixing and aeration technologies at Big Sky WWTP highlights the importance of tailored, high-performance solutions in modern wastewater treatment – particularly in regions with extreme climates and sustainability-focused goals.

The operators of the municipal wastewater treatment plant Vodovody a kanalizace Prerov a. s. in the Czech city of Prerov commissioned INVENT to replace their old roots blowers with four iTURBO^®-Blowers. These are doubly efficient: reducing electricity consumption by 36% and increasing the amount of the provided air by 65%.

Efficient submerged aeration systems in wastewater treatment involves an air supply to compress the air for discharge beneath the water surface. INVENT has designed an advanced turbo blower and implemented manufacturing techniques that allow every blower to be customized to the unique requirement of each wastewater treatment plant. This ensures the energy consumption and operating range is optimized for the specific process. The result is a dedicated machine operating at peak performance.

First installation in the Czech Republic

The wastewater treatment plant in Prerov in the eastern part of the Czech Republic, commissioned in 1969, is designed for a municipal capacity of 95,000 p.e. (population equivalent). In addition, the wastewater from a nearby sugar beet factory is discharged into the plant between October and February. In the late 1990s, several expansions were carried out to counteract the increasing hydraulic pressure on the facility. The installation of an iTURBO^®-Blower took place in Prerov when the blowers for the disc aerators installed in the aeration tanks were successfully replaced in 2020.

Optimization of Energy Consumption

Several INVENT products have already been installed at the facility to optimize energy usage: 2017 the robust hyperboloid-shaped, HYPERCLASSIC^®-Mixers for the anaerobic tanks and 2022 innovative, high-quality CYBERSLUDGE^®-Mixers for the digesters. Using a Computational Fluid Dynamics (CFD) analysis, also developed by INVENT, and additional fine-tuning, maximum efficiency was achieved for the iTURBO^®-Blower. A comprehensive analysis of the potential energy savings at the Prerov wastewater treatment plant convinced the operators to replace the four old 132 kW machines with four units of the more efficient 75 kW iTURBO^®-Blowers. This resulted in a 36% reduction in electricity consumption for blowers and a 65% increase of the provided air to the aeration system (from 10,802 m³/day to 17,847 m³/day).

Space and Noise Reduction

The building that housed the old blowers was able to be repurposed. The significantly more compact size of the iTURBO^®-Blowers even created additional storage space. The noise level was also noticeably reduced thanks to the quieter iTURBO^®-Blowers.

Conclusion

The project in Prerov clearly demonstrates the advantages of the iTURBO^®-Blower technology, both in terms of energy efficiency as well as space and noise reduction. It highlights INVENT‘s expertise in developing customized solutions that optimally meet the specific requirements of wastewater treatment plant operators.