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Project Report

Enhancing aeration efficiency at Rotorua

By Project Report
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Enhancing aeration efficiency at Rotorua WWTP New Zealand with iTURBO®-Blowers

As part of our ongoing commitment to delivering high-efficiency, sustainable solutions for municipal wastewater treatment, INVENT has successfully supplied and commissioned four iTURBO®-Blowers at the Rotorua Wastewater Treatment Plant in New Zealand. The project was executed in close cooperation with our regional partner, Jonassen Industrial Projects Ltd..

Project background

Rotorua WWTP is operated by Rotorua Lakes Council and is a key facility in the Bay of Plenty region, treating both municipal and industrial wastewater from the urban area. The plant currently uses an activated sludge process and is undergoing a major upgrade program to meet higher environmental standards and accommodate future population growth.

One of the major focuses of the upgrade is the improvement of aeration efficiency, which historically accounts for over 50% of the total energy demand in the biological treatment stage. To meet this objective, INVENT‘s high-performance iTURBO®-Blower was selected to replace aging blowers and provide a more efficient and reliable solution.

Scope of supply

Four iTURBO®-Blowers with 160 kW input power to each blower delivering up to 6000 Nm3/hr @ 70 kPa discharge pressure. Fully integrated units to replace aging blowers including:

  • 155 kW high-speed permanent magnet synchronous motors (PMSM)
  • Direct-drive turbo impellers
  • Built-in variable frequency drive (VFD)
  • Integrated Siemens industrial PLC control and communications
  • Advanced monitoring with HD touchscreen HMI
Implementation and results

All four iTURBO®-Blowers were successfully installed and commissioned in 2021. Since commissioning, they have demonstrated:

  • Significant energy savings compared to legacy systems (up to 30% reduction observed)
  • Stable and responsive oxygen supply for the biological process
  • Minimal noise emissions, contributing to an improved working environment (<78 dB(A))
  • Reduced maintenance requirements, with air filter replacements being the only regular service task

The integration into the existing SCADA system enables real-time monitoring, fault diagnostics, and performance optimization, supporting the plant’s operational efficiency and reliability.

Technical advantages of the iTURBO®-Blower

Energy efficiency: Optimized isentropic efficiency and minimal mechanical losses

Compact footprint: Integrated design reduces installation space and simplifies layout

Digital intelligence: Adaptive control algorithms respond to changing load conditions

High quality build: Baked power coated enclosure with full 316 stainless steel fasteners and fittings for long term projection from the sulfurous volcanic atmosphere

Sustainability: Contributes to a measurable reduction in CO₂ emissions and lifecycle costs

Additional projects in New Zealand

Following the success in Rotorua, iTURBO®-Blowers have also been installed at other key wastewater treatment facilities across New Zealand:

  • Green Bay WWTP Dunedin, 3 iTURBO®-Blowers commissioned 2024
  • Shotover WWTP Queenstown, 3 iTURBO®-Blowers commissioned 2025
Conclusion

The Rotorua WWTP project highlights the capability of INVENT’s iTURBO®-Blower to deliver tangible improvements in energy efficiency, operational reliability, and process control in modern wastewater treatment. We are proud to contribute to the long-term sustainability of municipal infrastructure in New Zealand.

Download the iTURBO®-Blower brochure now!
September 8, 2025
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Optimizing MBBRs with CFD

By Press Release, Project Report, Think Fluid Dynamix

Figure 1: Flow velocities experienced by the carriers in the IFAS reactor

Optimizing MBBRs with advanced CFD for Blue Plains Advanced WWTP

Wastewater treatment is a critical concern for industries and municipalities worldwide, and process optimization and energy savings are more important than ever. Among the array of treatment technologies for biological wastewater treatment, the Moving Bed Biofilm Reactor (MBBR) stands out as an efficient, compact, and low-maintenance solution. This article explores the critical role of Computational Fluid Dynamics (CFD) in optimizing MBBR design and performance.

MBBR Technology: A brief overview

MBBRs use vast numbers of small, floating polyethylene carriers, each offering a large surface area for bacterial growth. MBBRs offer several advantages, including compactness, operational flexibility, and robustness in handling high organic loads. These reactors rely on the interaction between wastewater, biofilm-covered carriers, and a controlled environment (often involving aeration). Energy efficient treatment depends on maximizing the contact between these elements. Key design factors, influencing this interaction, include:

  • Reactor Geometry: Tank size, shape, and configuration directly impact fluid mixing and carrier dispersion. Poor design can lead to dead zones and reduced treatment efficiency.
  • Carrier Fill Ratio: Balancing sufficient biofilm surface area with adequate carrier movement is crucial. Overfilling can hinder circulation and promote clogging.
  • Aeration System Design: Uniform oxygen distribution is essential for microbial activity. The aeration system also plays a role in carrier mixing.
  • Flow Distribution: Even flow distribution prevents stagnation and short-circuiting, ensuring consistent contact between wastewater and biofilm.
CFD and the challenge of simulating MBBRs

CFD is a field of engineering that uses numerical analysis and data structures to simulate and predict fluid flow, heat transfer, and related phenomena by discretizing the governing equations of fluid mechanics (such as the Navier-Stokes equations). In the wastewater treatment industry, CFD helps to simulate, evaluate and optimize processes such as mixing, aeration, chemical dosing, hydraulic distributions, etc. From activated sludge tanks to more advanced systems like Moving Bed Biofilm Reactors (MBBRs), CFD insights lead to improved operational efficiency, lower costs, and more reliable compliance with environmental regulations.

CFD modeling of MBBRs has enormous advantages, but is far from simple. MBBR systems can contain hundreds of millions of carriers. Simulating the drag force, collision dynamics, individual trajectories of each carrier, a two-way coupling (fluid-carrier interaction) quickly escalates into a highly complex problem from computational perspective. The true challenge lies in modeling each individual carrier, as they come in a variety of shapes, sizes and densities.

Replicating the detailed internal structures of each carrier in CFD is computationally prohibitive. As a result, simplified representations of the original problem become necessary. These simplifications introduce a number of modeling uncertainties and, therefore, no matter how sophisticated the CFD code, empirical data remains essential for grounding simulations in reality.

Advanced CFD modeling: a DEM and calibration with experimental data

THINK Fluid Dynamix® now developed a solution to these challenges: a numerical model that couples the Discrete Element Method (DEM) with CFD to simulate both the fluid flow and the carrier particles. The fluid-carrier interaction is calibrated using experimental data from a series of mixing tests for each carrier type.

DEM is a numerical technique primarily used to model the behavior of collections of individual particles in processes where particle-particle and particle-boundary interactions play dominant roles. When DEM is coupled with CFD, it enables simultaneous simulation of the fluid flow around (and through) these particles, as well as the particles’ motion due to fluid forces and inter-particle collisions. This coupling is crucial for accurately predicting the overall behavior of liquid-solid flows.

In practice, DEM often relies on basic geometrical shapes (such as spheres, cubes, or cylinders) to represent carrier particles because replicating detailed internal structures in CFD is computationally impractical. Therefore, the methodology uses these simplified geometries but calibrates parameters – such as collision properties, effective density, and representative size – against physical experiments. Specifically, the behavior of a given carrier type is observed in a reactor over a range of mixing intensities to match simulation outcomes with experimental data.

The calibration procedure proceeds as follows:

  • Measuring Carrier Dynamics: Conduct physical experiments in a mechanically stirred tank reactor to track how carriers behave under known flow conditions (mixing intensities).
  • Adjusting Model Coefficients: Tune friction coefficients, collision parameters, representative density, and size until the simulation results align with the experimental measurements.
  • Scaling Up: Once calibrated, the numerical model can be reliably applied to full-scale reactors.

Figure 2: Test tank at the facility (left) and the CFD simulated tank at initial conditions (right)

Figure 3: Simulation of resuspension test of carrier media at specific operating condition

Case Study: DC Water Project at Blue Plains Advanced WWTP

The Blue Plains Advanced Wastewater Treatment Plant initiated a significant upgrade to convert its existing biological reactors into Integrated Fixed-Film Activated Sludge (IFAS) reactors, a variant of Moving Bed Biofilm Reactor (MBBR) technology. As a key component of this initiative, a full-scale pilot reactor was designed and analyzed using a coupled Computational Fluid Dynamics–Discrete Element Method (CFD-DEM). The primary objective of this pilot study was to thoroughly assess the hydraulic and mixing behavior anticipated from the introduction of IFAS media into an existing anoxic tank. The CFD simulations offered detailed insights into fluid flow and mixing phenomena, while critically incorporating the interactions between the IFAS media and the surrounding fluid environment.

The CFD-DEM analysis facilitated a comprehensive evaluation of mixing quality under various operating conditions. These conditions included different mixer configurations, various types of IFAS media, and multiple hydraulic residence times. The systematic examination of Key Performance Indicators (KPIs) to quantify mixing effectiveness included local flow velocities, the extent of carrier media homogenization throughout the reactor volume, the identification of potential dead or stagnant zones, and the detection of any short-circuiting phenomena.

This methodology played a crucial part in the engineering of the whole project, offering the ability to accurately quantify parameters and visualize intricate flow-media interactions within the reactor that are exceedingly difficult, if not impossible, to capture comprehensively through traditional experimental techniques, especially in full-scale, opaque environments. Moreover, employing numerical simulations for such assessments was considerably more cost-effective and time-efficient than relying on extensive physical pilot testing, allowing for the agile exploration of numerous design configurations and operational scenarios with significantly reduced financial and logistical outlay.

Figure 4: The multiphase CFD model of the IFAS reactor

Figure 5: Averaged streamlines of flow in IFAS reactor

Conclusion

This study represents a significant advancement in the modeling and optimization of Moving Bed Biofilm Reactors. By coupling CFD with the DEM and integrating rigorous experimental calibration, the work from THINK Fluid Dynamix® overcomes longstanding challenges in reliably simulating reactors that incorporate a diverse range of carrier media. Historically, the variability in carrier geometries and material properties has limited the predictive accuracy of purely numerical models. The experimental-numerical approach presented here not only validates the simulation framework but also offers detailed insights into the complex fluid dynamics and mixing phenomena inherent to these systems.

Notably, the disruptive project undertaken for DC Water at the Blue Plains Advanced Wastewater Treatment Plant serves as a compelling demonstration of this novel methodology. For the first time, a full-scale pilot reactor was analyzed using the calibrated CFD-DEM model, enabling precise evaluation of key performance parameters such as flow velocities, carrier dispersion, and the identification of stagnant or dead zones under various operating conditions. This case study underscores the practical utility of the approach and its potential to enhance reactor performance, energy efficiency, and treatment efficacy.

Overall, the integration of numerical techniques with experimental calibration establishes a new benchmark for the predictive modeling of MBBR systems. The breakthrough enhances the reliability of reactor design and optimization while laying the groundwork for future research and technological advances in wastewater treatment.

Authors: Efraim Riess-Gonzales and Averil Fernandez, M.Eng.

Find out more about THINK Fluid Dynamix®!

In this video you will learn about THINK Fluid Dynamix® and its team!

THINK Fluid Dynamix® presentation

Learn more about THINK Fluid Dynamix® and our team.

August 26, 2025
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Elimination of Micro-Pollutants

By Project Report
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ARA Thunersee uses HYPERCLASSIC®-Mixers for the elimination of micro-pollutants

The increasing pollution of our waterways by micro-contaminants from medicines, cleaning agents, and personal care products in waste water is a growing problem for humans and animals.

EXCURSUS ON THE FOURTH STAGE OF TREATMENT

Due to the incomplete metabolism of pharmaceuticals and the improper disposal of personal care products and chemicals, ever-increasing amounts of micropollutants are entering the wastewater requiring treatment. Conventional three-stage wastewater treatment plants, with mechanical, biological, and chemical treatment stages, are not designed to remove these micropollutants. If it cannot be ensured with measures at the source, i.e., avoidance or behavioral change, that these substances do not enter the wastewater in the first place, the existing wastewater treatment plant must be expanded to include a fourth treatment stage. This expansion step has been underway for many years in some regions in Germany, and also in Switzerland.

Within the fourth treatment stage, two different types of processes have been established so far:

  • ozonation with the aim of oxidizing trace substances
  • the use of activated carbon with the aim of adsorbing the contaminants.

In particular, the powdered activated carbon (PAC) process in combination with coagulation and flocculation is a proven and effective solution.

OPTIMIZATION OF PROCESSES

For the elimination of micropollutants using the INVENT HYPERCLASSIC®-Mixer, the focus is on the process variant with PAC. One example is Thunersee wastewater treatment plant in Switzerland, where the so-called “Ulmer Verfahren” has been implemented since 2018. In this process PAC is added to and mixed with the treated wastewater from the secondary clarification stage in a contact reactor. By adding coagulants and flocculants, loaded PAC flocs grow, which can subsequently be separated in 2 sedimentation step downstream.

The effectiveness of the process depends on the contact reactor design and the mixing technology used. Optimizing the individual stages enables the plant operator to ensure safe and efficient operation in terms of both energy and chemical consumption. INVENT offers a service for this purpose with its own department for computational fluid dynamics simulations, THINK Fluid Dynamix®, which determines the optimal positioning of all inlets, chemical dosing points, and agitators in order to achieve maximum mixing and stable flocculation with minimal energy input. With the HYPERCLASSIC®-Mixer, INVENT also offers the optimal technology for mixing a contact reactors. The hyperboloid mixer is positioned close to the bottom, generating high radial bottom velocities for efficient suspension. The mixer’s high pumping capacity enables an overall strong volume flow for reliable homogenization of the reactor contents. The HYPERCLASSIC®-Mixer is also ideal for flocculation, as the acceleration of the flocs generated along the large surface of the hyperboloid mixer body is gentle. The low-shear yet intensive mixing creates optimal conditions for floc growth, hence, the desired cleaning process.

The flocs, containing micropollutants, can then be separated in the downstream sedimentation stage and recirculated. Good settling properties of the flakes are extremely important here in order to prevent activated carbon carry-over with the treated effluent. At the end of the process, the loaded activated carbon is discharged with the waste sludge, dried and incinerated.

INVENT AND ARA THUNERSEE – A SUCCESS STORY SINCE 1996

The Thunersee municipal wastewater treatment plant in Switzerland has been in operation since 1972 and treats the wastewater of around 120,000 connected residents.

Between 1994 and 1998, as part of a complete overhaul of the biology and sludge treatment, twelve fourth-generation INVENT HYPERCLASSIC®-Mixers were installed in the anoxic tank sections for denitrification on a total of four lines. These have now been running continuously for over 25 years, with low maintenance and high energy efficiency. As of 2024 old mixing units are being gradually exchanged for the new HYPERCLASSIC®-Mixers Evolution 7 to update the technology and adapt to the now more challenging situation with heavier PAC-loaded activated sludge on the biology.

INVENT provided support during the planning phase for the fourth treatment stage by optimizing the 4-stage contact reactors, while THINK Fluid Dynamix® answered related questions based on preliminary plans using flow simulations:

  • determination of the optimal inflow position of PAC suspension
  • flocculants and flocculating agents in the first and last tank sections,
  • determination of residence times and degree of homogenization of the tank contents.

Suspending the heavier PAC sludge with a sludge volume index of 80 to 40 ml/g requires more mixing power than, for example, simple denitrification. In addition, the requirements for homogenization and floc growth pose a challenge for the mixing technology used.

Since the fourth generation of HYPERCLASSIC®-Mixers was installed in the aeration tank in 1996, INVENT has continuously worked on improving its mixer, so that the completely redesigned version of the HYPERCLASSIC®-Mixer Evolution 7 was now available for use in the fourth treatment stage of the Thunersee wwtp. The HYPERCLASSIC®-Mixer Evolution 7 efficiently generates a high bottom velocity in the reactor with low shear force, and the optimized design of the transport fins on the hyperboloid mixer body increases the homogenization performance.

The expansion of the plant has been in operation since July 2018, and the positive results show, that not only is the fourth treatment stage a complete success, but also that the placement of the inlets and mixers recommended by INVENT based on fluid mechanics was correctly analyzed. The officially published report on the results of the wastewater treatment plant’s first year of operation describes the chosen designs as follows: “After secondary clarification of the biological stage, the wastewater is lifted by two pumping stations and conveyed to two contact basins with a capacity of 1,100 m3. The wastewater passes through four zones equipped with INVENT mixers, with no partition between zones 2 and 3.”1 This effect of a ‘virtual wall’ between two counter-rotating HYPERCLASSIC®-Mixers is a unique effect which, combined with good retention time behavior, can save on construction costs for a partition between the zones. The report goes on to describe the process: “The powdered activated carbon suspension and Fe3+ solution are dosed into the first zone. […] An anionic flocculant is added in the fourth mixing zone at the bottom of the tank near the mixer. The PAC sludge is settled in four clarifiers, each with a capacity of 1,944 m3 […], and conveyed to the first mixing zone of the contact tanks by return sludge pumps.”1

In order to test the effectiveness of the plant, intensive water comparison tests were carried out before and after the fourth purification stage during the first year. In the report mentioned above, 22 of a total of 24 48-hour samples were reported to have elimination rates of 81% to 95%, which is above the legally required 80% for the specified indicator substances. The two poorer values were attributed to heavy rainfall, as in this case 10% to 20% of the water bypassed the fourth treatment stage, consisting of a contact reactor, sedimentation basin, and filter system.

 

1 Report on the results of the wastewater treatment plant’s first year of operation

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August 7, 2025
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Project Up-scaling Big Sky, Montana

By News, Project Report
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Big Sky WWTP Scales Up with INVENT’s Hyperboloid Technology

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.

Find out more about the HYPERCLASSIC®-Mixer!
May 16, 2025
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Project Report iTURBO in Prerov, CZ

By News, Project Report
  • wwtp Prerov_iTURBO Blower_610x440
  • wwtp Prerov_HYPERCLASSIC Mixer_610x440

Energy-efficient and powerful: The iTURBO®-Blower Solution in Prerov, CZ

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.

Find out more about the iTURBO®-Blower!
April 22, 2025
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WRF Ocotillo, Chandler, Arizona

By Project Report
  • HYPERCLASSIC Mixer with CYBERPROP in Ocotillo Chandler WRF
  • CFD WRF Chandler
  • Overview Ocotillo WRF
  • HYPERCLASSIC Mixer after installation

Progressive Water Reclamation: Ocotillo Facility’s State-of-the-Art Transformation in Chandler, Arizona

The Ocotillo Water Reclamation Facility (WRF) in Chandler, Arizona, USA – where water reuse is essential – plays a crucial role in sustainable water management. Recognizing this, the City of Chandler has invested in cutting-edge wastewater treatment and reclamation facilities to supply reclaimed water to parks, businesses, golf courses, and city-owned aquifer recharge sites.

To ensure the Ocotillo WRF can meet future demands, the existing 18 MGD treatment facility required an upgrade to its biological process and headworks. Wilson Engineers led the design improvements, while McCarthy Building Companies executed the construction.

As part of this upgrade, new anoxic zone mixers were needed to support the facility’s advanced biological activated sludge treatment. Given the high-performance requirements, INVENT provided a customized solution, that met all engineering expectations. The INVENT HYPCERCLASSIC®-Mixers Evolution 7 were selected for their efficiency and reliability. Additionally, due to the 26-ft depth of the anoxic basins, the INVENT CYBERPROP-Mixer was integrated to enhance vertical mixing without increasing energy consumption.

The CYBERPROP-Mixer is an innovative propeller blade mounted higher on the HYPERCLASSIC®-Mixer’s vertical shaft. Rotating at the same velocity as the mixer body, it improves homogenization without additional energy input, further optimizing process efficiency.

To further enhance performance INVENT’s CFD department THINK Fluid Dynamix® conducted an advanced CFD flow simulation to optimize the inlet structure of the anoxic basins. The study revealed that a simple baffle plate could significantly improve flow dynamics. Based on these findings, a baffle plate was installed, ensuring more effective basin hydraulics.

With these upgrades, the Ocotillo WRF is now better equipped to meet future water reclamation challenges, supporting Chandler’s long-term sustainability goals.

Find out more about the HYPERCLASSIC®-Mixer
February 24, 2025
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Project Report Manchester and Silicon Valley, USA

By Project Report
  • INVENT USA Manchester HYPERCLASSIC
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  • INVENT Hyperclassic Manchester Conneticut
  • Silicon Valley INVENT USA

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!

Find out more about the HYPERCLASSIC®-Mixing and Aeration System
December 16, 2024
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Project Report Lafayette, CO, USA

By Project Report
  • 2_INVENT Lafayette wwtp HCMA Beitrag1
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Cutting-edge technology in use for a more sustainable water supply in Lafayette

The development of sustainable water treatment is a critical challenge for the growing city of Lafayette, Colorado, situated at the edge of the Rocky Mountains. Since 2022, the city has been constructing a new high-performance plant to enhance the region’s water supply using state-of-the-art wastewater treatment technologies. A central feature of this plant is the installation of 13 highly efficient HYPERCLASSIC®-Mixing and Aeration Systems from INVENT, designed specifically for challenging wastewater treatment conditions.

Lafayette has long partnered in major water projects aimed at enhancing regional resilience against changing climatic conditions. Alongside developing new water reservoirs, wastewater treatment is becoming increasingly vital for sustaining prosperity and growth in the area.

Following the planning, delivery and installation of the first HYPERCLASSIC®-Mixing and Aeration System by INVENT in the sludge holding tank, twelve further systems were installed by 2023 after the successful operation of the first unit. These high-performance systems primarily focus on sludge stabilization in the sludge basin through mixing and aeration as well as efficient oxygen input to reduce the biological (BOD) and chemical (COD) oxygen demand in the aerated basins. Thanks to the fluid mechanically optimized technology, the 13 HYPERCLASSIC®-Mixing and Aeration Systems prove to be just as efficient and reliable in continuous operation as they are in intermittent operation:

  • Improved sludge quality: The unique hyperboloid-shaped mixer body creates an optimized near-bottom flow that stirs up deposits and ensures a more homogeneous distribution of the sludge.
  • Efficient aeration: The mechanical aeration generates optimally sized air bubbles, which are evenly distributed in the basin by the rotation of the mixer body. This improves the oxygen input while reducing energy consumption. A significant reduction in operating costs is possible.
  • Decoupled Mixing and Aeration: The aeration basins have the ability to create anoxic or aerated zones within the plant by simply turning the air off while continuing to mix. This feature allows operators optimal flexibility in the process trains.
  • Reduced maintenance: The construction and design of the mixing and aeration system is designed for continuous or intermittent operation. Overall maintenance has been minimized by a top-mounted dry drive, which reduces maintenance costs but not having to drain the basins And ensures long-term operational stability.

Developed for use in demanding wastewater applications, the HYPERCLASSIC®-Mixing and Aeration Systems form a central element of Lafayette’s innovative and environmentally conscious water supply structure. With a daily volume of up to 6.4 million gallons of water (MGD) – the equivalent of filling more than 20 large swimming pools – the city, in collaboration with INVENT, demonstrates that modern, high-performance water treatment solutions can be successfully implemented, showcasing their effectiveness and reliability.

Find out more about the HYPERCLASSIC®-Mixing and Aeration System
November 5, 2024
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Project Report from Salt Lake City

By Project Report
  • HYPERCLASSIC Mixer

Water Reclamation Excellence achieved by INVENT

The Central Valley Water Reclamation Facility (CVWRF) in Salt Lake City will play a pivotal role in the sustainable management of water resources in the region. INVENT is contributing to the facility’s pioneering role by supplying and installing 30 energy-efficient HYPERCLASSIC®-Mixers in the new biological nutrient removal process. This collaboration will position the CVWRF as a beacon of innovation and sustainability in the field of water management.

Nestled in the heart of Central Valley, this state-of-the-art facility demonstrates the commitment of environmental stewardship and water conservation in Salt Lake City. Covering a sprawling area, the facility is equipped with cutting-edge technology designed to treat and reclaim water efficiently. The primary objective is to ensure that water discharged from various sources undergoes rigorous treatment processes, meeting stringent effluent Nitrogen and Phosphorous quality standards before being released back into the environment.

The facility will employ a multi-stage treatment process that begins with the removal of solid particles through screening and sedimentation. Subsequently, advanced biological nutrient removal (BNR) treatment methods will be employed to remove total phosphorus (TP) and total nitrogen (TN), ensuring the effluent will meet the stringent effluent limits set by State of Utah.

BNR treatment systems are known to have large sections of biological treatment operating with lower oxygen levels (anoxic ) or even without any oxygen (anaerobic). To ensure the biology will remain suspended during these phases, efficient mixing of the wastewater is required. Efforts to maximize energy efficiency and minimize maintenance, Central Valley Water Reclamation Facility plant owners decided to apply the INVENT HYPERCLASSIC®-Mixers for this task.

In the Anoxic zones of the newly constructed aeration basins, sixteen of INVENT’s 8ft diameter HYPERCLASSIC®-Mixers evo 7 will be used to keep the biology suspended. Furthermore, twelve mixers will be used to suspend the anaerobic basins, and two will be used to suspend the return activated sludge. Alongside the 30 HYPERCLASSIC®-Mixers evo 7, CVWRF will also have INVENT mixers in their chlorination channel and side stream nutrient removal facility.

During design, INVENT Environmental Technologies Inc. advised CVWRF to use the newest mixer-body design, the HYPERCLASSIC®-Mixer evo 7. The new mixer was introduced to optimize mixing efficiency at even lower energy consumption. The research for this innovative mixer was performed by INVENT and applied modern computational fluid dynamics (CFD modelling) and 3D printing for rapid prototyping. While this new type of mixer is already used on various large plants worldwide, the CVWRF was the first to use this type of mixer in the state of Utah.

In conclusion, the Central Valley Water Reclamation Facility will set a standard for responsible water reclamation practices through its comprehensive biological treatment processes and the implementation of modern energy efficient treatment equipment. In an era where water scarcity is a global concern, the Central Valley Water Reclamation Facility will stand-s as a testament to the power of proactive and environmentally conscious water management.

Learn more about our HYPERCLASSIC®-Mixer
October 9, 2024
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Wastewater treatment in industrial park

By Project Report
  • HYPERDIVE Ruhrwerk im Becken
  • HYPERDIVE Ruhrwerk vor Installation
  • HYPERDIVE Ruhrwerke Montagehalle INVENT
  • INVENT AG/ INVENT HYPERCLASSIC-Mixer evolution 7

German Industrial Park equipped with three INVENT HYPERDIVE®-Mixers

In order to optimally treat the industrial wastewater of the Weinheim Industrial Park in Germany, INVENT’s mixers and experience were used. Three HYPERDIVE®-Mixers were able to be installed and put into operation.

Approximately 50 companies have settled in the Weinheim Industrial Park near Mannheim, Germany, in an area of more than 800,000 m². Nearly 6,500 employees go in and out every day. Of course, wastewater is also produced in a corresponding scale, which is biologically treated in the mixing and equalization basin belonging to the park.

For treatment, it is necessary to swirl up sludge near the bottom of  the basin and move it into a flow. To accomplish this, the HYPERDIVE®-Mixers from INVENT were chosen. These are submersible drive mixer systems that can be very easily integrated into already filled systems and do not require any bridge construction.

Functionality of the HYPERDIVE®-Mixer

The HYPERDIVE®-Mixer is a vertical mixer with a hyperboloid mixer body installed close to the ground and a submerged drive in a cage design. Due to its hyperboloid shape, it generates a strong radial bottom flow and thus keeps particles in suspension. It also ensures complete mixing of the feed flows. It is therefore  the optimum mixer for all suspending and homogenization tasks required for water and wastewater treatment, especially in very deep basins.

The tripod base is made of solid coated steel, making it sufficiently heavy to hold the HYPERDIVE®-Mixer firmly in place during operation and at rest. It holds the submersible drive and leads the electric cable past the mixer body. A stainless steel lifting cable is attached to the top of the frame and allows the entire unit to be easily lifted in and out. The drive shaft and hub connection of the HYPERDIVE®-Mixer are also made of high-quality stainless steel, making them highly resistant to corrosion.

The hyperboloid mixer body is connected to the lower end of the shaft via a shaft/hub connection. This enables easy and quick installation as well as easy detachment even after many years of operation. In operation , the connection is safely protected against spontaneous detachment. Due to the optimized shape and the transport ribs seamlessly integrated into the mixer body, the entire hyperboloid mixer is not only particularly efficient and streamlined, but also absolutely non-clogging.

The Weinheim Industrial Park has made the right choice

Those responsible for the Weinheim Industrial Park decided on HYPERDIVE®-Mixers and thus made the right choice. The submerged mixers were installed and put into operation within a very short time in 2022. Since they are made exclusively of high-quality materials and are virtually maintenance-free, wastewater treatment will hardly be on the industrial park’s agenda in the next few years.

Learn more about INVENTs industrial wastewater treatment
September 27, 2023
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