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Retrofitting wtp’s with hyperboloid flocculators

By aeisemannPress Release

Retrofitting water treatment plants with hyperboloid flocculators

Flocculation is a critical stage in water treatment, enabling suspended particles to aggregate into larger, settleable floc for removal. Effective flocculation requires a balance of chemical addition, mixing energy, and low shear to form stable floc. With rising regulatory and financial pressures, utilities are increasingly turning to retrofits of existing facilities to improve treatment efficiency at lower costs.

Floc forms through the neutralization of negatively charged particles by coagulants, followed by gentle mixing to promote collisions. Success depends on mixing intensity, measured by the velocity gradient (G), and on minimizing shear that can break floc apart. Beyond G-values, understanding energy distribution and flow dynamics within basins is essential to optimize performance. Computational Fluid Dynamics (CFD) has become a valuable tool to evaluate basin hydraulics, identify short-circuiting, and model the performance of different flocculator technologies.

Common flocculators include hydraulic baffles, paddle wheels, walking beams, bladed impellers, and hyperboloid mixers. Key evaluation factors include maintenance, flexibility, adjustability, energy, redundancy, energy transfer, shear, and floc quality.

The hyperboloid flocculator applies fluid dynamic principles to provide uniform mixing with minimal shear. Its hyperboloid-shaped body accelerates floc gradually along its ribs until particle velocity matches impeller speed, reducing tip shear concerns.

Installed near basin bottoms, hyperboloid mixers create radial flow patterns that sweep the tank floor, prevent sediment accumulation, and keep floc suspended. Variable frequency drives allow operators to adjust mixing intensity for water quality changes. The result is reduced maintenance, optimized chemical use, and improved floc formation.

Case Studies

Annapolis, Maryland (2015)

Replaced bladed impellers with hyperboloids.
Results: 30% reduction in alum use, less lime required, improved iron removal (1.0 → 0.5 ppm). Higher treatment capacity in smaller footprint, minimal maintenance, less sediment accumulation. CFD confirmed uniform mixing at all flows.

Figure 1: Comparison of data from the old and new Annapolis Plant
Figure 2: A drained basin after operation at the Hickory DWTP showing little to no sedimentation

Bellevue, Ohio (2019)

Replaced paddle wheels.
Results: Improved turbidity, quieter operation, ability to feed powdered activated carbon at floc stage.

Hickory, North Carolina (2013)

Replaced bladed impellers in one train.
Results: Less sediment buildup, slightly lower turbidity (0.22 NTU vs. 0.31 NTU with blades). Operators noted improved suspension of solids.

Atlanta, Georgia (Chattahoochee WTP)

Retrofit from paddle wheels to hyperboloids initially underperformed. CFD revealed basin short-circuiting; baffles were added.
Results: Dramatic turbidity improvement (0.15–0.50 NTU vs. 0.55–0.90 NTU in other trains).

Figures 3 +4: Before and after retrofitting the horizontal paddle wheels at the City of Atlanta, Georgia Chattahoochee Water Treatment Plant

Houston, Texas (2020)

Replaced paddle wheels.
Results: Significant reduction in tank sludge (1 inch vs. 10 feet). Water quality improved, though chemical changes prevented direct cost comparison.

Bzenek, Czech Republic (2007–2009)

Trial compared paddle wheels to hyperboloids then full retrofit.
Results: Optimal performance at 10 rpm across all mixers. Iron and manganese removal improved; turbidity and color decreased. Energy consumption reduced by 82%.

Conclusion

Retrofitting flocculation systems requires a holistic understanding of hydraulics, floc properties, and energy distribution. Evidence from multiple installations demonstrates that hyperboloid flocculators consistently deliver improved water quality, reduced chemical use, energy savings, and lower maintenance. As regulations tighten and budgets shrink, they represent a proven, cost-effective retrofit solution for modern water treatment.

Author: Jackie Lauer P.E., INVENT Environmental Technologies

November 20, 2025

Optimizing Aerobic Digestion

By aeckPress Release

A strategy for optimizing aerobic digestion: a cyclical process

A common misconception for aerobic digestion is that the process must be aerated 100% of the retention time. In redefining this outlook, it has been found that cycling between mixing and mixing while aerating proves to be more effective and energy efficient. By having the ability to turn the air off and on, the system creates aerobic and anoxic phases allowing for further nutrient reduction, improved dewaterability, and increased volatile sludge destruction. This supports endogenous respiration and nitrification. Many different technologies exist for aerobic digestion, and often multiple types of equipment must be combined to achieve the cyclical process. Fortunately, there are systems that can perform decoupled mixing and aerating with only one device.

Defining aerobic digestion

Aerobic digestion is a wastewater treatment process used to treat waste activated sludge or a mixture of sludges. Typical applications produce a sludge able to meet requirements for Class B biosolids, and retention times usually range from 40 to 60 days. Sludge destruction is primarily a direct function of sludge age and temperature shown in Figure 1 (Metcalf & Eddy, 2014).

Figure 1: Volatile solids reduction in an aerobic digester as a function of temperature and sludge age

Aerobic digesters can achieve thermophilic conditions which provide more rapid biochemical reactions and reduce the retention time 20 to 40 days typically. Thermophilic conditions can provide greater reduction in bacteria and viruses, meet Class A biosolid requirements when operating at 55º C or higher, and lower energy requirements than conventional aerobic digestion. Although advantageous to aerobic digestion, this article will not discuss thermophilic conditions further and focus only on the traditional aerobic digestion process.

Aerobic digestion is the degradation of the organic sludge in the presence of oxygen. Oxygen is introduced in the basin or tank to allow the micro-organisms in the sludge to convert the organic material to carbon dioxide and water, and the ammonia and amino species to nitrogen. Biochemical changes in an aerobic digester follow the subsequent equations:

Biomass destruction: Biomass + Oxygen → Carbon Dioxide + Water + Ammonium Bicarbonate

Nitrification: Ammonia + Oxygen → Nitrate + Hydrogen + Water

Overall Equation: Biomass + Oxygen → Carbon Dioxide + Water + Nitric Acid

Denitrification: Biomass + Nitrate → Carbon Dioxide + Nitrogen + Ammonia + Hydroxide

Complete Process: Biomass + Oxygen → Carbon Dioxide + Nitrogen + Water

Aerobic digestion is similar to the conventional activated sludge process but has longer retention times without a raw wastewater feed i.e. nourishment for the micro-organisms. When there is no new supply of organics for the micro-organisms, they die and become nourishment for other bacteria in the tank reducing the sludge organic solids concentration. This process is known as endogenous respiration. Aerobic digestion also has the ability to nitrify under certain conditions. Typical operations are controlled by pH; however, other parameters can be used to control the process.

Current technologies

Since both air and mixing are required for the aerobic digestion process, typical equipment may include coarse bubble aeration, jet aeration, surface aeration, and fine bubble aeration. To be able to do both, mixing and mixing while aerating, often times, multiple devices must be used.

Technologies exist with the capabilities to perform mixing and mixing while aerating, eliminating the need for two different systems. For the ability to cycle between mixing and mixing while aerating, the INVENT HYPERCLASSIC^®-Mixing and Aeration System has proven suitable for the application. The system provides the ability to mechanically mix and aerate for aerobic digesters. The air can be turned off while still mixing, creating anoxic conditions so that denitrification can occur. This system provides optimal control of a process that was once mostly inflexible and has significant advantages over other systems such as e.g. surface aerators (see Fig. 2).

Oxygen distribution with insufficient mixing –
poor purification performance

Oxygen distribution with good mixing & homogenization –
excellent purification performance

Figure 2: Surface aerator vs. hyperboloid mixer/aerator

The alpha value

With 2% or higher mixed liquor suspended solids (MLSS), mechanical mixing is required due to the viscosity of the liquid because air alone will not provide sufficient mixing. As the percent solids increase, there is a correlation with a decrease in the alpha value. The alpha value is the interference to oxygen transfer efficiency, and data indicates that there is strong correlation between fluid viscosity and oxygen transfer efficiency. In the article “Digester Aeration Design at High Solids Concentration”, research has shown that with fine bubble diffusers, the alpha value falls below 0.1 around 3% MLSS (Schoenenberger, Shaw, Redmon, 2003).

When the alpha value falls below 0.1, this can lead to unwanted anaerobic conditions causing odor and foaming, the HYPERCLASSIC^®-Mixing and Aeration System provides higher alpha values as the mechanical nature of the device pushes oxygen deeper into the sludge flocs. The alpha value for solids ranging up to 5% can be around 0.27 for this mixing and aeration system. This results from the mechanical mixing, which allows for the distribution of air throughout the tank, and system providing a small to medium bubble for better oxygen transfer.

Cycling between mixing and mixing while aerating

Unlike the over-aeration from conventional continuous aerated mixing, a decoupled mixing and aeration system provides control over the entire aerobic digestion process through oxygen supply and/or mixing. Different parameters must be established to control the aerobic digestion process, both time and ORP (oxidation reduction potential) can be used to control the cycling between mixing and mixing while aerating alongside pH.

Since solids reduction is typically the main goal of aerobic digestion, changes in pH dictate the ability to destruct the biomass. When pH drops, alkalinity addition becomes necessary to combat poor dewaterability of the sludge. When the air is cycled off, alkalinity can be restored through nitrate destruction (denitrification). This off/on air cycle can now decrease the need for chemicals that are necessary for continuously aerated systems.

Nitrification can also be a main goal of aerobic digestion and is advantageous when ammonia in the digestate is of concern at the head of a plant. Starting with mixing and aerating, the biomass in the system destructs creating carbon dioxide, water, and ammonium bicarbonate. With air still being introduced into the system, nitrification can now happen converting ammonium to nitrate, hydrogen, and water. If air is always on, this continued process can drop pH and consume alkalinity. Now, introducing long periods of mixing only, the aerobic digester essentially becomes anoxic/anaerobic with zero oxygen throughout the entire basin. This cycle begins the denitrification process where nitrate combines with the hydrogen from the nitrification to form nitrogen and water, and in the presence of biomass, also creates carbon dioxide and ammonia. Denitrification restores pH by returning alkalinity back into the system. With the pH restored, the aerobic digesters can turn air on beginning the cycle over again. At the end of the process, the digestate now has up to 20% less ammonia returning back to the head of the plant.

The HYPERCLASSIC^®-Mixing and Aeration System: An overview

By enabling the operator to have more control over the aerobic digestion process, plants have the ability to reduce cost, reduce chemical needs, and increase energy savings with cyclical aerobic digestion. With the HYPERCLASSIC^®-Mixing and Aeration System, mixing energy is dissipated at the point of air introduction creating a surface area of constantly renewed air bubbles when air is turned on while maintaining sufficient mixing when air is turned off. This creates the ideal environment for cyclical aerobic digestion.

The system itself has a hyperboloid mixer body that is non-clogging and has integrated transport ribs for optimal fluid acceleration. There is consistent backpressure and aeration efficiency that allows for no deterioration of efficiency over time providing the ability to turn the air on and off whenever necessary. Even with high MLSS, the Mixing and Aeration System is robust, and also easy to maintain and operate. The system only requires above water maintenance on the dry mounted gear motor, and inspection on the bottom guide mounted to the floor of the tank every few years. The system is able to operate at varying water levels, with the ability to drain the tank or basin completely with no harm to the system when decanting or during the removal of the sludge. This makes the decanting process streamlined and easy due to the sludge being continuously mixed even as the water level is decreasing.

Intensive mixing is important to prevent settling on the bottom of the tank, and with poor mixing, oxygen gradients can occur. Since the mixer body of the HYPERCLASSIC^®-Mixing and Aeration System is installed close to the bottom of the tank, oxygen gradients are prevented and a homogeneous sludge is created. Air is generated from the sparger ring underneath the mixer body. There the air escapes and meets the uniquely shaped underside of the mixer body, which is equipped with dispersing tunnels and special shear fins. As the mixer body rotates, the air in the dispersing tunnels is mixed intensively with the wastewater which creates a dissolution of coarse to fine bubbles by the shear fins. The main flow then transports these bubbles radially outwards and distributes them throughout the whole tank.

Figure 3: Schematic representation of HYPERCLASSIC^®-Mixing and Aeration System

Real world applications

With any technology, real-world applications and data show if a system works. The HYPERCLASSIC^®-Mixing and Aeration System has been installed in digesters around the world proving to be a suitable application for cyclical aerobic digestion. In the United States, there have been multiple aerobic digestion installations with process success. The oldest running aerobic digesters with these Mixing and Aeration Systems in the United States have been running since 2006 at the Jacksonville Beach WWTP (see Fig. 4).

Figure 4: WWTP Jacksonville Beach, Florida

The aerobic digesters at Jacksonville Beach treat to 3% solids in three circular tanks and provide a consistent quality feed to their sludge dewatering process. The sludge treated continues to meet Class B standards efficiently, and the operators are very satisfied with their choice and the resulting wastewater treatment. Another installation is across the country in Meridian, CO (see Fig. 5).

Figure 5: WWTP Meridian, Colorado

They have an aerobic digestion lagoon system completed in 2020 with two HYPERCLASSIC^®-Mixing and Aeration Systems. The operator has the ability to run the them at varying water depths with ease, and there is little to no smell when the standing directly over the basin. Sludge is treated to 2.5% solids at half the capacity of the previous design. This has helped decrease energy costs and increase process performance.

Summary

The cyclical process used in aerobic digestion has proven successful in both solids reduction and nitrification. The INVENT HYPERCLASSIC^®-Mixing and Aeration System has proven suitable through real installations even at high percent solids. With the ability to cycle the air on and off while mixing, the system provides flexibility for the operator and the operation. The systems robustness and mechanical reliability make it a top choice for aerobic digesters.

Author: Jackie Lauer P.E.

November 15, 2025

CFD Solutions for CYBERFLOW

Groundbreaking CFD solutions for wastewater treatment: The CYBERFLOW^®-Accelerator

INVENT Umwelt- und Verfahrenstechnik AG, a company with deep roots in fluid mechanics at the University of Erlangen-Nuremberg, has been a pioneer in CFD simulations for wastewater applications since its creation. Recognizing their potential, INVENT established THINK Fluid Dynamix^®, a specialized business unit offering advanced CFD-based engineering solutions for the water, wastewater, and chemical industries.

The challenge of wastewater modeling

Modeling hydraulic processes in wastewater treatment requires more than just technical expertise—it calls for a multidisciplinary team with practical, on-the-ground experience. Achieving optimal results involves not only simulating fluid behavior but also understanding the intricate interactions between chemistry, biology, solids handling, civil engineering, material selection, equipment integration, and cost-efficiency.

With over 30 years of experience and a technical unit combining broad technical knowledge and deep industry insight, THINK Fluid Dynamix^® delivers dependable and innovative solutions tailored to real-world challenges.

CFD simulations bring a wide range of advantages to wastewater treatment, including enhanced process efficiency, reduced operational costs, and greater environmental sustainability. These digital tools are applied to a variety of systems and processes — from inflow screening and analyzing flow distribution in channels and pipelines, to optimizing mixing and aeration in tanks, assessing the behavior of oxidation ditches, clarifiers, anaerobic digesters, and more. Additionally, these simulations are used in product development, such as the CYBERFLOW^®-Accelerator, allowing for the design and validation of innovative treatment components and equipment before physical prototypes are built.

Figure 1: CFD simulation of the CYBREFLOW^®-Accelerator

The CYBERFLOW^®-Accelerator

To make the INVENT CYBERFLOW^®-Accelerator a revolutionary flow generator it introduces innovative design principles.

This is made possible by a holistic, fluid mechanical optimization approach, which considers not only on the propeller design, but the interaction of the flow with the entire machine.

This approach focuses on optimizing all aspects for the design and application including:

Turned flow direction for vortex free flow pattern:
Conventional flow generators suffer from turbulent inflow hitting the propeller, causing major efficiency losses. The CYBERFLOW^®-Accelerator eliminates this issue by ensuring a completely undisturbed upstream flow, enabling higher flow rates with less energy input.

“Anti-vortex” fin:
Standard propellers generate inefficient radial and tangential flows that create vortices and waste energy. The CYBERFLOW^®-Accelerator uses an anti-vortex fin to eliminate these losses and recover energy by converting unwanted flow components into useful axial flow.

INVENT Power Trim Technology^®:
Instead of aligning the shaft horizontally like traditional systems, the CYBERFLOW^®-Accelerator angles it slightly upward. This reduces friction at the tank bottom and improves efficiency

Fluid mechanically optimized base frame:
The optimized base frame avoids bulky rectangular tubes and instead uses cast metal structures with minimal surface and drag. This fluid-optimized design minimizes resistance and maximizes flow efficiency.

Conclusion

The CYBERFLOW^®-Accelerator show cases the possibilities behind computational fluid dynamics (CFD) in wastewater treatment. Engineered through advanced CFD simulations and a holistic design philosophy, each design element is purpose-built to enhance performance, reduce operational costs, and support sustainable treatment processes. As a result, the CYBERFLOW^®-Accelerator is more than just a product; it is a demonstration of how THINK Fluid Dynamix^® transforms deep scientific understanding into powerful, real-world engineering solutions for the future of water and wastewater treatment.

Figure 2: CYBREFLOW^®-Accelerator

Author: Lea Diehl

November 10, 2025

Unleash the SBR’s full potential

By aeckPress Release

How to unleash the Sequencing Batch Reactor’s full potential

A Sequencing Batch Reactor (SBR) is a fill-and-draw type of conventional activated sludge treatment system. This approach was developed over a century ago and has proven to reliably treat municipal and industrial wastewater. More recent developments in wastewater treatment technology have made the SBR even more of an advantageous treatment method. With a variety of technologies available, it’s important to understand both attributes and challenges presented by the SBR to ensure the best possible outcome for a project.

Fill-and-draw batch processes have been applied in wastewater treatment since the early 1900’s when Ardern, Lockett, and Fowler developed the activated sludge processes (ASP) process in their laboratories in Manchester, UK (Ardern and Lockett 1914, Ardern and Lockett 2015). Since the development of the ASP, continuous flow ASP dominated over the fill-and-draw batch processes due to the lack of automation that we have today. In years past, manually adjusting valves, switching on and off pumps and the lack of level controls etc. made the process onerous. However, the development of control systems and mechanical equipment in the 1960’s, 1970s, and 1980’s (Pasveer 1958, Irvine 1971, Wilderer and Schroeder 1986) laid the foundation for reviving the SBR process as a solution for municipal and industrial wastewater treatment. While the SBR process was quickly becoming more popular in small and medium sized plants, another approach to the SBR process was developed: the cyclic activated sludge process (Goronszy 1979, 1985, Demoulin and Goronszy 1997, Demoulin et. al 1999). It was developed and applied in larger wastewater treatment plants using the process names CASS¹ and ICEAS². Similarly, more recently developed processes incorporate cyclic activated sludge reactors which are continuously fed with fresh wastewater while treated water is intermittently decanted from the reactor.

In more recent years was the development of a new SBR process, the Aerobic Granular Sludge (AGS) Process Technology, (de Bruin et. al 2004, Prout et. al 2015, Prout et. al 2017) which has received a lot of attention. An advantage of this process is the production of larger sludge granules than that of conventional activated sludge flocs. Larger flocs mean faster sludge settling. This larger floc size also allows for an anaerobic core, an anoxic mid layer and an aerobic outer layer in a single sludge granule compiling anaerobic, anoxic and aerobic driven process steps (e.g. P‐Removal, Denitrification, and Nitrification) (see Figure 1).

Figure 1: Aerobic Granular Sludge Floc

If properly designed , AGS applications offer the potential for achieving:

Higher MLSS without the use of plastic carriers
Better settleability
Reduced reactor volumes
Smaller footprints
Shorter cycle times
Lower capital investments
Higher process safety
No need of internal re‐circulation pumps
Less sludge production
Decreased energy consumption
Reduced operating costs

This is why few commercial wastewater treatment system providers, other than the Dutch pioneer Royal Haskoning DMV, have attempted to develop, establish and market their own adaptions of the AGS. All current AGS advancements are based on the SBR principle of using one or more complete mixed reactor(s) where the AGS is supposed to develop. This means to unleash the potential advantages of the AGS process, challenges which come along with the SBR concept, listed below, must be mastered.

Precise hydraulic and load equalization of the flow is required and usually leads to large upstream mixing and equalization
It is necessary to overdesign the mechanical equipment because of limited runtime per process
Accurately scaling up from lab‐scale and/or pilot scale to life-size and large-scale plants is challenging and requires in-depth understanding of fluid mechanics to be more reproducible.
The prerequisite of obtaining completely mixed reactors can significantly limit the reactor, process, and equipment

Some technologies require precise equalization of hydraulics and loading. Controlled anaerobic feeding of raw wastewater into the settled sludge blanket is crucial for the kick‐off of granular sludge formations. To achieve this, the most common approach is to feed the reactor through a bottom feeder with flow throughout the bottom of the entire reactor and install a static decanter at the water surface as illustrated in Figure 2.

Figure 2: Typical AGS Reactor configuration with bottom feeder and static surface decanter

This approach works best in smaller circular or rectangular tanks with pipe works providing equal distribution of the raw wastewater throughout the bottom of reactor with the use of a static decanter at the top and when the required piping does not become too complex and expensive and does not result in too much of a hydraulic loss. The approach limits the volume per reactor module to smaller volumes and is the reason why these plants require large equalization basins upstream of the biological reactors, because an equal flow distribution at the bottom can only be achieved for the one exact hydraulic flow to the reactor for which the feed systems was designed for. The slightest deviations from the designed influent flow will lead to non‐uniform feed and distribution of raw wastewater in the sludge blanket, improper functioning of the static decanter and the operation of the plant as a whole. A further disadvantage of the bottom feeder system is the high hydraulic loss which is required to achieve equal flow distribution across the bottom of the reactor. Treatment dependence on precise flow makes treatment performance sensitive to minor flow fluctuations which can be caused by something as simple as sludge clogging the feeder piping.

Batch wastewater treatment often suffers from discontinuous operation of main equipment such as pumps, mixers, aeration systems, blowers, etc. resulting in over design of equipment Instead of selecting and designing these expensive components for continuous operation, the equipment, depending on the cycle strategy needs to be selected to pump, mix, aerate and decant the wastewater in a fraction of a 24 hour day.

An example of this for the aeration system and blowers is provided in Figure 3, below. In a continuous flow process the aeration system design is made based on daily actual oxygen requirement (AOR). Since the aeration system must continuously supply the oxygen to the constant inflowing raw wastewater, the required hourly capacity of the aeration system can be calculated by dividing the daily AOR value by 24. This value is the benchmark which is set to 100. Peaking factors are neglected since they apply in both cases. Typical SBR cycles can vary from 3 to 6 hours resulting in 8 to 4 cycles per day respectively.

The cycle incorporates the following phases: fresh feed of wastewater, mixing, aeration, settling, and decanting. Assuming that only 3h per cycle can be used for aeration and we use a cycle strategy with 4 cycles a day the total aeration time per day is only 12h instead of 24h. Therefore, the installed aeration system capacity needs to be 2 times for batch processes than what is required by continuous flow reactors with the same capacity. For example, if 2,000 diffuser elements are required for a continuous flow system project, 4,000 are required for a batch process with the same aeration depth. This applies to other equipment as well (e.g. 6 vs 12 blowers or 450 kW vs 900 kW respectively). All of which must be purchased, installed, and maintained resulting in greater capital and operations and maintenance costs.

Some SBR processes’ aeration phases overlap with the fill phases resulting in lowered water depth in the reactor reducing the overall aeration efficiency causing the aeration system design has to compensate. This applies to other equipment such as pumps and piping. This example demonstrates the necessity of investing in processes alternatives with holistic designs which consider processes, reactor, and other equipment.

Precise up-scaling of processes and reactor designs from lab‐scale to pilot scale and from pilot scale to large scale; and possibly from large scale to even larger scale can be extremely challenging. Scale‐up ratios of 1:10 are usually straight forward, but the potential to make mistakes is plentiful. To successfully up-scale not only geometrical similarity is important, but also reactor behavior and retention time must to be maintained. If not all scale‐up targets can be met at the same time and an experienced engineer must decide which parameters are most important.

An example is that lab‐scale basic principles are often examined in circular vessels of a dimension of 200 – 300 mm and volumes are measured in liters. Equipment for mixing, aeration and pumping comes from the laboratory and/or a local aquarium shop. This setup usually is sufficient to prove feasibility and to determine basic parameters such as air flow and biological reduction rates. However, because of the size of the reactors, mixing is usually not the limiting process due to the oversized air bubbles providing an abundance of mixing along with the oxygen transfer. This step up from lab‐scale to pilot scale is the reasonably poses the first challenge because aquarium and lab equipment usually is not available on a larger scale and industrial-sized equipment usually is not available in pilot scale. Therefore large scale equipment is often used in pilot‐scale and the similarity of lab‐scale and pilot‐scale very often cannot be truly reproducible. This is not necessarily a problem as long as the process works in pilot scale and the process parameters can be adjusted accurately. The transfer from pilot scale to large scale (e.g. 20m³ to 1,500m³) is more challenging, but manageable. This step is not successfully achieved due to the limited availability of large scale basins and because of the challenge of achieving geometric similarity of the large scale basins. For aeration system design, the floor coverage is almost never similar and feed piping usually has to follow real live availability and budget restrictions. The list of challenges associated with up-scaling go on, but with a thorough understanding of fluid dynamics and wastewater treatment this process can be more accurate and reproducible.

Figure 3: iC³ – Reactor Module

This process leverages the unique features of the HYPERCLASSIC^®-Mixing and Aeration System (Hoefken et. al. 1991, Hoefken et. al. 1993, Hoefken 1994, Hoefken et. al. 2001, Hoefken et. al. 2004) which is ideally suited for intermittent processes

The primary feature of the INVENT SBR is characterized by the iC³ reactor module which is a drawn‐out rectangular basin with multiple HYPERCLASSIC^®-Mixing and Aeration Systems mounted in series to create individual complete mixed zones (cascaded).Wastewater continuously enters through a specially designed inflow distributor at one end and clear treated water intermittently leaves the reactor through operated decanting systems on the opposite end. This design makes it possible develop and operate an optimized SBR cycle strategy which can vary from zone to zone. Figure 3 shows an iC³ Reactor module in a schematic representation.

Summary

This article summarizes the history of SBRs and the development of the INVENT iSBR^®/iGSR^® process. Over the course of 30 years, various challenges related to the overall design and scaling up of the processes have been overcome to achieve groundbreaking results with modern SBR systems. These features include:

Continuous feed with intermittent decanting
Multiple cascaded full-mix reactors per SBR module, and Holistic process, reactor, and plant design.

Authors: Dr.-Ing. Marcus Hoefken, Megan House, Dr. rer. nat. Peter Huber, and Dipl.-Ing. Walter Steidl

October 28, 2025

Find out more about THINK Fluid Dynamix^®!

Optimizing MBBRs with CFD

By aeisemannPress 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.

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

Modern interpretation of the SBR-Process

iSBR^®/iGSR^®-Process – INVENT’s modern interpretation of the Sequencing Batch Reactor Process

Since we have started our business activities in the early nineties we have been in love with the so called Sequencing Batch Reactor process (SBR) for the biological treatment of municipal or industrial wastewater. Batch processes have the great advantage that the reactor behavior is defined, the boundary conditions stay constant and unexpected events are unlikely to occur while running the treatment cycle.

The INVENT HYPERCLASSIC^®-Mixing and Aeration System from the very beginning has been the core of each SBR plant we designed and built. The System can effectively mix without aeration and at a different time efficiently aerate and mix the biomass. This is why it is the ideal basis for SBR and any cyclic or intermittent process.

Figure 1: Schematic diagram of the HYPERCLASSIC^®-Mixing and Aeration System

One of our core competencies has always been to deeply understand and analyze fluid mechanical correlations and to use this understanding to design superior products for the water and wastewater industry.

The focus of our activities is on the essential unit processes

Mixing
Mass transfer
Solid/liquid separation

In these areas good fluid mechanical design can make a real difference and improve overall process efficiency and save energy. This is how whole product families of advanced mixing systems, highly efficient aeration systems, high performance decanters and innovative filters developed over time.

A second of our core competencies is to deeply understand the treatment processes and to know how to integrate our products into our client’s processes most beneficially.

This inevitably led to a deep understanding of the in and outs and specific requirements of SBRs and a dedicated family of products for this special process.

These include:

Each product can be sized and customized for the individual plant and application to perfectly match each client’s needs and specifications.

In cases in which the client wishes to benefit from and make use of our experience and expertise we can offer our design and engineering package along with our hardware package. We can complement this integrated hard- and software package with installation supervision, start-up and training and supply a complete SBR package. We call this in case of a conventional process design iSBR^® and in case of a granular sludge process iGSR^®. These complete systems can be used in all common wastewater treatment applications such as e.g.

Municipal wastewater treatment
Industrial wastewater treatment
De-ammonification process
Granular Sludge processes

The four main areas in which we have achieved improvements compared to conventional systems in the market are

the key equipment,
the overall reactor design,
the overall process design, and
the overall fluid mechanical design

Overall reactor design

The iSBR^®/iGSR^® reactor design is based on the idea of creating several individual zones in one reactor module, which are positioned in series. This design, which only works thanks to the unique features of the HYPERCLASSIC^®-Mixing and Aeration System, allows for the realization of an advanced process which has

Cascaded reactor design
Runs continuously
And cyclic

We call this iC³-Process.

Cascaded reactor design

Each HYPERCLASSIC^®-Mixing and Aeration System creates an individual zone which are cascaded over the entire reactor. This allows for a much higher process flexibility since we can run different modes and process parameter in the individual zones during the same cycle. The first zones for example can act as a selector while the last zone is decanting.

The individual steps of the iSBR^®/iGSR^®-Process

We differentiate the five different process phases, which happen at different times and four different spatial zones (Zones 1 – i). These zones are defined by the 4 different spatial zones of equal size in which we can divide each SBR tank.

Overall process design

The continuous inflow and the division of the reactor in individual zones allows for an advanced process design which is explained in this paragraph.

In figure 3 the five basic cycle phases of the iSBR^®/iGSR^®-Process are shown schematically. After phase 5 the cycle repeats itself and jumps back to phase 1. What happens in the individual phases is as follows.

Figure 2: The five main cycle phases of the iSBR^®/iGSR^®-Process

1 Fill/Mix (FM)

In this phase the HYPERCLASSIC^®-Mixing and Aeration System operates at reduced speed and provides mixing without aeration. Anaerobic conditions due to the continuous filling of wastewater are generated in zones 1 and 2; whereas there are mainly anoxic conditions in zones 3 and 4. In zones 3 and 4 the necessary anaerobic conditions are generated for a partial degradation of organic compounds, which may not be degraded under solely aerobic conditions, and also for biological phosphorus removal.

2 Fill/Mix/Aerate (FMA)

During the aeration cycle filling continues and the HYPERCLASSIC^®-Mixing and Aeration System operates at high speed in strong mixing and aeration mode. It efficiently supplies the necessary oxygen for the BOD and COD removal and the nitrification process. Effective mechanical mixing during aeration is very important to maintain and ensure high α-values, to maintain high oxygen transfer rates and to apply the necessary minimum shear stress on the granular biomass.

The HYPERCLASSIC^®-Mixing and Aeration System is a proven technology for aeration in bioreactors with granular sludge. Mechanical mixing during aeration is also desirable to avoid foaming and scum on the water surface. The strong mixing furthermore ensures aerobic conditions and a minimized anaerobic core in the sludge flocs.

Due to the high oxygen demand resulting from the feed of fresh wastewater to Zone 1 of the iSBR^®, Zone 1 stays during this phase mainly anoxic.

3 Fill/Degas (FDg)

After the aeration cycle has been completed and the blowers have been turned off a short period of strong mixing at increased speed of the HYPERCLASSIC^®-Mixing and Aeration System takes place. By this an effective degassing of the sludge flocs is achieved. This improves the sludge settling properties and avoids collection of foam on the water surface.

4 Fill/Settle/Slow Mix 1 (FSPh1)

Due to the anoxic conditions during the settling phase, denitrification processes take place in the first zones of the iSBR^® and the HYPERCLASSIC^®-Mixing and Aeration System at the inlet of the iSBR^®/iGSR^® operates at low speed and gently mixes the fresh wastewater with the increasing sludge blanket at the bottom. At this low speed the sludge blanket is maintained at the desired depth. The feed of raw wastewater into the sludge blanket creates, after a short anoxic phase, anaerobic conditions with Bio-P release. Additionally these anaerobic conditions promote the conversion of bCOD1 to rbCOD2 in the inlet zone (Zone 1) of the iSBR^®/iGSR^® with anaerobic uptake of rbCOD and/or anoxic depletion of the same. This minimizes aerobic uptake of rbCOD, and creates the optimum biochemistry for aerobic granular sludge growth.

5 Fill/Decant/Slow Mix 2 (FDPh2)

During this last step of the iSBR^®/iGSR^®-Process the wastewater inflow into the sludge blanket and the operation of the HYPERCLASSIC^®-Mixing and Aeration System at low speed continues. Anaerobic conditions necessary for Bio-P. are created within the sludge blanket.

In this final phase the iDEC^® begins to withdraw the treated effluent (decant) without disturbing the sludge blanket by our waste sludge retrieval system and thus preventing a contamination of the effluent with sludge. During this phase the excess sludge is removed from the settled blanket to maintain the required food to mass ratio for the process design. As soon as the decanting cycle has been completed and the desired discharge volume has been withdrawn from the iSBR^®/iGSR^®, the decanter raises to its idle position above the water level and the cycle repeats itself.

¹ bCOD: biodegradable chemical oxygen demand

² rbCOD: readily biodegradable chemical oxygen demand

iSBR^®/iGSR^® benefits

Continuous flow operation

The INVENT iSBR^®/iGSR^®-Process uniquely combines the advantages of a batch wise operation with conventional continuous flow across the entire plant. This unique achievement makes large equalization basins in front of the biological reactors unnecessary and further reduces the overall footprint of the plant.

Modular design

Our INVENT iSBR^®/iGSR^® are based on a modular design. The individual modules consist of either a single or a double train of HYPERCLASSIC^®-Mixer/Aerators and 3, 4, 5, 6 or i of them in series. The size of the base modules selected depends on the overall plant capacity which is required, the local conditions and the overall design approach. We prefer plant designs with several individual modules because they offer a higher flexibility and operational safety.

Unique equipment package

INVENT’s unique equipment package used in the iSBR^®/iGSR^®-Process sets us apart from all other approaches on the market. The flow conditions we can create with the INVENT HYPERCLASSIC^®-Mixing and Aeration System are unparalleled and make this process possible. The virtual wall effect ensures the desired reactor behavior. The versatile mixing conditions allow for the safe granular sludge growth. The high aeration performance and quick response times facilitate reliable process control. And if you compare the HYPERCLASSIC^®-Mixing and Aeration System with standard membrane aeration systems which are still commonly used, it has a significantly higher performance under process conditions (α- value) and most importantly it does not age and does not loose aeration performance over time.

Our iDEC^®-SBR Decanter allows for short decanting times. Our high efficiency iTURBO^® High-Speed Blower further reduces the energy consumption and our iFILT^®-Diamond Filter can further reduce the amount of suspended solids in the effluent if locally required or if the water shall be re-used e.g. for irrigation purposes. But the star is the team. Having developed all this products in house means that we could optimally design them for the purpose and the use in INVENT iSBR^®s and iGSR^®s and they optimally work with each other to supply the highest performance in each INVENT project.

Reactor design

Our iSBR^®/iGSR^®-Design is optimized for this special process and for the equipment used. It allows for maximum mass transfer optimal reactor behavior, small overall footprint and high operational safety and performance. For the reactor design Typical Flow Diagram of an iSBR^®/iGSR^® plant we use the most modern fluid mechanical simulation tools as well as dynamic simulation for the optimization of the overall process performance and specific load conditions.

Process design

The unique iSBR^®/iGSR^®-Process allows for aerobic granular sludge production under continuous flow conditions. This is only possible using a cascade of complete mixed stirred tank reactors we create with HYPERCLASSIC^®-Mixing and Aeration System and the cyclic process conditions.

Summary

INVENT over the years has been improving the Sequencing Batch Reactor process and is now offering the advanced proprietary iC³-Process in its iSBR^®/iGSR^® packages to selected clients.

Authors: Dr. Peter Huber, Marcel Huijboom and Dr. Marcus Höfken, INVENT Umwelt- und Verfahrenstechnik AG, Germany

June 4, 2025

INVENT – 30 Years + Annual Report 2024

30 years, one mission: the INVENT success story continues – for clean water worldwide

Innovative strength and the certainty to do the right thing – this is the foundation on which one of the world’s leading water and wastewater treatment companies was able to emerge from a university research project in just three decades. A success that the 150 employees of INVENT Umwelt- und Verfahrenstechnik AG are celebrating together in 2025. However, it will not stop at looking back. INVENT sees its 30-year success story above all as an incentive to courageously push ahead with new projects, even in challenging times – in a commitment to the responsible use of one of the most valuable resources of our time: Water.

When an innovative scientific project was formed at the Chair of Fluid Mechanics at the Friedrich-Alexander University Erlangen-Nuremberg, Germany, in 1995, it not only marked the birth of INVENT, but also the start of ambitious new developments for modern water and wastewater treatment. In 2025 INVENT looks back on the successes achieved with joy and honors them with a summer anniversary celebration to which around 300 employees, companions and partners from three decades of the company are invited.

“With a highly specialized, energy-saving product range and innovative process technology, we have set new standards for the biological wastewater treatment of the future. As a result, we are now one of the top 5 in the industry worldwide – a great success and at the same time a driving force for future innovations,” says Dr. Marcus Höfken, founder and current CEO of INVENT, summarizing the company’s success story.

2024: Solid annual financial statements in challenging times

In the economic turbulence of the recent past, success cannot be taken for granted. INVENT is therefore all the more satisfied at the end of a year in which the German mechanical engineering industry registered a drop in turnover of over 7%. In contrast to the industry trend, INVENT was able to match the previous year’s record pre-tax profit. Incoming orders also remained at a stable high level in 2024 after the record year 2023 (over EUR 40 million).

Commitment to Germany as a business location

In times when there sometimes is too much talk about challenges and too little about opportunities, INVENT remains committed to Germany as a business location. The expansion of the production facility in Erlangen-Dechsendorf continued in 2024. The modern plant now offers optimal conditions for the production of the iFILT^®-Diamond Filter, an innovative product in tertiary wastewater treatment that sets new standards with its performance, sophisticated energy and resource efficiency – especially in the fight against microplastics and trace substances.

In addition, construction work began on a new production hall at the headquarters in Erlangen-Eltersdorf in 2025, which will expand production capacity and secure the location in the heart of Central Franconia in the long run.

International location decisions bring resilience in challenging times

INVENT is rooted in Germany and at home in the world. International expansion therefore remains a central component of the corporate strategy.

INVENT subsidiaries were founded in Argentina and Uruguay in 2024 to strengthen access to the growth markets in South America.
The USA remains a key market for INVENT, which is why the company plans to open its own production site in South Carolina in 2025. It will mark a new chapter in the North American strategy and guarantee optimal options for action locally, even in times of customs disputes.

Dr. Marcus Höfken: “North and South America are becoming increasingly important for us. The current developments confirm our decisions to expand our local sites. They allow us to act faster, more flexibly and with a greater focus on our customers.

A lasting mission: working for clean water worldwide with innovative solutions

In its commitment to global trade, INVENT is committed to a strong drive; it is the same mission that laid the foundation for 30 years of successful innovation: “Our goal remains to be a technological leader – and at the same time to be perceived as a powerful partner in the water industry worldwide. We want to contribute to solving water problems all over the world with high-quality future technologies – and we are ready to be present wherever our solutions are needed,” says Dr. Marcus Höfken.

For INVENT Umwelt- und Verfahrenstechnik AG, there is no doubt that the demand for innovative water and wastewater technology will continue to grow worldwide. The company’s course is therefore set, even in challenging times: INVENT remains focused on growth with a spirit of invention, a sense of responsibility and passion – in Europe, in America, worldwide.

May 30, 2025

Check out our iGSR^® video!

Products for Oil, Gas and Petrochemical Industry

By aeisemannPress Release

Wastewater Treatment for the Oil, Gas and Petrochemical Industry

INVENT develops, produces and distributes innovative mechanical equipment, process technology and plants for the treatment of water and wastewater. The company became well known through the development and market introduction of energy-saving and multitasking hyperboloid mixers as well as mixing and aeration systems for wastewater treatment.

INVENT offers a wide range of efficient stirring and mixing solutions for almost every application in the water, wastewater and processing industry. In the field of aeration technology the scope of products includes a variety of membrane aeration systems for biological wastewater treatment which have been developed and optimized for different applications. These are distinguishable by their functional principle, construction and material, so that an optimal solution can be offered for almost all industrial and municipal requirements. The layout and design of an optimum mixing and/or aeration system is a very complex task. It requires a large amount of competence, know-how and experience. In the case of industrial plants e.g. in the oil, chemical or petrochemical industry, it is most important to understand the production process to a certain degree because this significantly influences the wastewater composition.

An INVENT system solution comprises, depending on the customer’s requirements, the plant design, basic and detailed engineering, project management, delivery of the mechanical components, installation of the plant and the training of plant personnel. The mechanical components, such as mixers, aeration systems, filter, pumps, blowers, fittings and instrumentation, control and automation systems, are carefully selected for an INVENT system solution and coordinated with each other. INVENT takes responsibility for the entire scope of the delivery. This approach reduces the number of interfaces and potential sources of failure.

The recently launched INVENT Granular Sludge Reactor (iGSR^®) is the first system that fully exploits the potential of granular activated sludge also for large plants: Reduced process times, higher purification performance with a reduced footprint, low energy consumption and reduced life cycle costs, at the same time delivering high reliability. Its modular concept can be adapted to any plant size. Its design offers a higher level of process stability for hydraulic peaks and load fluctuations than any other system. The iGSR^® is already in operation in various plants worldwide, with more facilities currently under construction.

INVENT’s engineering and consulting services range from fluid mechanical optimization of hydraulic structures or processes (Think Fluid Dynamix^®) to solving chemical engineering problems, flow simulations using CFD or simulations of entire wastewater treatment plants. These tasks are supported by laboratory research, if necessary.

We offer turnkey solutions for your water project in the oil, gas and petrochemical industry!

February 11, 2025

Floating solution for pond treatment plants

click here for the product video

Floating HYPERCLASSIC^®-Mixing and Aeration System conquers Swedish industrial plants

The innovative Floating HYPERCLASSIC^®-Mixing and Aeration System gaining popularity in industrial plants across Sweden, particularly in lagoon wastewater treatment facilities operated by pulp and paper manufacturers. These facilities are specifically designed to address the challenges associated with wastewater treatment and require efficient aeration technologies.

In Sweden, lagoon wastewater treatment plants are widely utilized for treating wastewater from the pulp and paper industry. However, traditional aeration technologies such as surface aerators, membrane aerators, and submerged aerators often encounter issues such as underutilization of volume, poor circulation, and high maintenance requirements. The HYPERCLASSIC^®-Mixing and Aeration System is the solution to these challenges by being mounted on a floating platform, enabling aeration close to the bottom and ensuring effective mixing of wastewater through high turbulence.

The adoption of the HYPERCLASSIC^®-Mixing and Aeration System has resulted in significant improvements in treatment performance at wastewater treatment plants within the global process industry. Notable enhancements include increased mixed volume, extended mixing range, and improved sludge quality. Additionally, the system’s flexibility and robustness contribute to reduced maintenance costs.

One example involves the replacement of a membrane aeration system in a Swedish industrial wastewater treatment plant with a lagoon capacity of approximately 50,000 m³. By utilizing the HYPERCLASSIC^®-Mixing and Aeration System, aeration performance increased by approximately 30% without the need for additional blowers. This led to reduced maintenance costs and overall more efficient wastewater treatment.

In another case, a Swedish industrial wastewater treatment plant replaced three surface aerators with just one HYPERCLASSIC^®-Mixing and Aeration System in 2021 This resulted in consistent dissolved oxygen concentrations near the shore. Maintenance requirements decreased significantly, with only an oil change needed every two years. The system’s flexibility allows for adjustments in aeration capacity or switching to agitation mode without aeration to prevent sludge deposits on the lagoon floor.

In the north of Sweden, an industrial wastewater treatment plant retrofitted its lagoon with six mixing and aeration systems and two mixing systems to accommodate higher production volumes. Consequently, some surface and submersible aerators previously in use were decommissioned. The HYPERCLASSIC^®-Mixing and Aeration System is mounted on a floating steel platform, with an optional maintenance platform for easy access during oil changes. Connected to a compressed air supply, the system does not require any other fixed or high-maintenance equipment in the tank. Installation on land and subsequent lifting into the lagoon are straightforward. Once secured in place and connected to the process air, the system can be put into operation.

The meticulously planned design facilitates straightforward installation on land and seamless lifting into the lagoon afterward, as illustrated. Lastly, the Floating HYPERCLASSIC^®-Mixing and Aeration System is securely positioned as intended, connected to the process air, and put into operation.

INVENT‘s extensive expertise in wastewater treatment is evident in the successful deployment of the Floating HYPERCLASSIC^®-Mixing and Aeration System. Engineers in Erlangen consistently develop comprehensive solutions tailored to meet specific needs. The production of these systems primarily utilizes regional materials and services. Since its inception in 2019, the floating mixing and aeration system has proven to be highly effective and is gaining popularity not only in Sweden but also in other regions.

September 9, 2024