Biological Treatment

  • Aqua-Aerobic
  • MBBR
  • IFAS
  • AvN
  • inDENSE
  • Lagoon Systems

  • AquaNereda
  • AquaSBR
  • AquaDDM
  • Aqua MixAir
  • AquaPass
  • Aqua MSBR
  • Aqua BioMax



The AquaNereda® Aerobic Granular Sludge Technology is an innovative biological wastewater treatment technology that provides advanced treatment using the unique features of aerobic granular biomass. The unique process features of the AquaNereda technology translate into a flexible and compact process that offers energy efficiency and significantly lower chemical consumption.

An aerobic granular biomass is comprised of compact granules, which are a layered microbial community that provides superb settling properties. Within a single tank, the process creates proper conditions to develop and reliably maintain a stable granule, without a supplemental carrier. The layered aerobic and anaerobic zones within the granule allow for simultaneous processes to take place in the granular biomass, including enhanced biological phosphorus reduction, and simultaneous nitrification and denitrification.


Retrofit of existing tanks, increasing treatment capacity
Upgrade of existing treatment systems to meet BNR requirements
New plant construction
Municipal and industrial

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AquaNereda Brochure 2017 AquaNereda Brochure 2017 (741 KB)



The AquaSBR® sequencing batch reactor provides true batch reactor technology with all phases of treatment accomplished in a single reactor. All components are easily accessible and the advanced decant system ensures optimum quality effluent withdrawal.

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AquaSBR brochure 2018 AquaSBR brochure 2018 (625 KB)



Operation of the AquaDDM® Mixer

The AquaDDM establishes a powerful down-flow mixing pattern that transports surface liquid downward and increases mass transfer. Flow entrainment and regenerative flow create high reactor turnover rates for efficient mixing.

Ideal Solution for Anoxic Mixing

The AquaDDM® is the ideal mixer for use in anoxic basins for denitrification and phosphorus reduction and provides unrivaled mixing and uniform top-to-bottom blending of the basin. Unlike horizontal mixers, side-entering mixers and submersible mixers, the AquaDDM® provides efficient intermixing of the basin contents - and does not employ any gear reducers, submerged bearings or submerged seals. The AquaDDM® will greatly reduce or eliminate short circuiting, and eliminate dead spots in the basin.

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AquaDDM Brochure 2012 AquaDDM Brochure 2012 (3355 KB)


Aqua MixAir

The Aqua MixAir® system provides separate mixing with the AquaDDM® Direct Drive Mixer and an aeration source such as the Aqua-Jet® surface aerator or Aqua-Aerobic diffused aeration. The system has the capability to cyclically operate aeration and mixing to promote anoxic/aerobic and anaerobic environments with low energy consumption.



The AquaPASS system incorporates the unique flexibility of a time-managed process configured in a flow-through activated sludge scheme. The system employs time-based aerobic and anoxic phasing via the Aqua MixAir system to meet critical nutrient removal objectives. Independent aeration and mixing allows necessary nitrification, denitrification, as well as phosphorus removal to occur within a single basin. This concept also decreases overall power consumption of the system. The AquaPASS system utilizes four (4) treatment steps: Anaerobic, Staged Aeration (multiple discrete anoxic/aerobic events), Phase Separator, and Pre-Anoxic. The stage functions can be designed for optimum conditions based on wastewater characteristics to meet specific effluent objectives.

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AquaPASS Brochure AquaPASS Brochure (1348 KB)



The Aqua MSBR system utilizes the Aqua MixAir system by providing separate mixing with AquaDDM® direct-drive mixers and an aeration source of Aqua-Aerobic diffused aeration. This system has the capability to cyclically operate the aeration and mixing to promote anoxic/ aerobic and anaerobic environments with low energy consumption. In addition, the Aqua MixAir system can achieve and recover alkalinity through denitrification, prevent nitrogen gas disruption in the settling phase, promote biological phosphorus removal, and control certain forms of filamentous bacteria.

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AquaMSBR Brochure 2012 AquaMSBR Brochure 2012 (3356 KB)


Aqua BioMax

Dual Treatment System

The Aqua BioMax dual treatment system is a unique combination of rotating biological contactor (RBC) technology and cloth media filtration. The package unit utilizes multiple RBC disks that are vertically mounted and closely spaced on a steel shaft, providing a large surface area for bio film growth. The disks rotate out of the wastewater to provide aeration for efficient BOD removal and nitrification. A cloth media drum filter follows the RBC to collect and remove the biological solids prior to the effluent discharge. This cloth media filter eliminates the need for a secondary clarifier. The Aqua BioMax system is an ideal solution for low flow applications (up to 100,000 gpd) where economical treatment and simple operation are critical.

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AquaBioMax Brochure 2012 AquaBioMax Brochure 2012 (826 KB)

World Water Works

MBBR: World Water WorksMoving Bed Biofilm Reactor (MBBR) technology

Moving Bed Biofilm Reactor technology

Moving Bed Biofilm Reactor (MBBR) processes improve reliability, simplify operation, and require less space than traditional wastewater treatment systems.

MBBR technology employs thousands of polyethylene biofilm carriers operating in mixed motion within an aerated wastewater treatment basin. Each individual biocarrier increases productivity through providing protected surface area to support the growth of heterotrophic and autotrophic bacteria within its cells. It is this high-density population of bacteria that achieves high-rate biodegradation within the system, while also offering process reliability and ease of operation.

This technology provides cost-effective treatment with minimal maintenance since MBBR processes self-maintain an optimum level of productive biofilm. Additionally, the biofilm attached to the mobile biocarriers within the system automatically responds to load fluctuations.

Process BenefitsMedia

Compact Design
A fraction of the size of conventional systems

Capacity can be easily upgraded by simply increasing the fill fraction of biofilm carriers

Single Pass Process
No return activated sludge stream required

Load Responsive
Actively sloughed biofilm automatically responds to load fluctuations
Minimal Maintenance
No F/M ratios or MLSS levels to maintain

MBBR processes are an excellent solution for common wastewater applications including:

  • BOD Reduction
  • Nitrification
  • Total Nitrogen Removal


Moving Bed Biofilm Reactor systems deliver a flexible, cost-effective, and easy-to-operate means to address current wastewater requirements and the expandability to meet future loads or more stringent discharge requirements within a compact design.

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WWW - MBBR Brochure WWW - MBBR Brochure (1049 KB)

World Water Works

IFAS: World Water Works

Integrated Fixed-Film Activated Sludge

Integrated Fixed Film Activated Sludge (IFAS) process is a state-of-the-art biological process used in treatment of municipal and industrial wastewaters for BOD removal, nitrification and denitrification. The process is a hybrid of suspended growth and fixed-film (attached growth) process and may be viewed as a combination of Activated Sludge and MBBR process. It is simply an Activated Sludge process with submerged but floating plastic media in aeration tank.  The plastic media is usually made of HDPE, polyethylene or polypropylene with specific gravity less than 1.0. In addition to the suspended growth bacteria in the aeration tank, the large surface area of the plastics provide abundant surface for bacterial growth. This increases the overall biomass concentration in the aeration tank enabling it to treat higher loads at lower reactor volume. It is usually assumed that most of the BOD removal is done by the suspended growth bacteria while most of the nitrification is performed by the nitrifiers that grow on the plastic media. Medium or coarse bubble diffusers uniformly placed at the bottom of the reactor maintains a dissolved oxygen (DO) concentration of > 3 mg/L. To retain the media flowing out of the tank, screens are placed on the downstream walls. A clarifier or a DAF is placed downstream of the MBBR tank to separate the biomass and the solids from the wastewater. The concentrated sludge from the clarifier/DAF is recycled to the aeration tank as in an Activated Sludge process. 

For denitrification, anoxic IFAS tanks are used. The anoxic tank is similar to aerobic MBBR tank described above except that no oxygen is supplied. The tank contains no diffusers and the media is kept in suspension in the reactor through submersible mixers. Other feature such as the screen is the same as aerobic reactor although the design may be slightly different.

There are hundreds of IFAS installations worldwide. IFAS is used in treating municipal wastewaters and the industrial wastewaters including effluents from food and beverage plants, steel mills, oil refineries, petrochemicals, chemical plants, paper mills and any industries requiring wastewater treatment for BOD removal, nitrification and denitrification. IFAS is widely used for upgrading existing Activated Sludge plants designed for BOD removal only to nitrification and nitrogen removal.

World Water Works


A new process control system offered by World Water Works that controls the important balance between Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB). AvN utilizes a patented process that applies selective pressure to aid in the segregation of the desired bacterial populations. This allows wastewater treatment systems to achieve more efficient removal of Total Nitrogen in the mainstream process at the lowest total energy cost possible.This unique technology can achieve very high removal rates of TN with very little carbon.

World Water Works


inDENSE™ technology solves the problem of floating or bulking sludge which can affect the treatment capacity and performance of many of wastewater treatment facilities. The inDENSE™ technology uses hydrocyclones to generate separate sludge streams based on their density. The lighter fraction, made up of poorer settling sludge is wasted from the plant, while the denser, better settling sludge is retained in the system. This selective wasting practice can greatly improve the wastewater treatment facility's sludge settling volume index (SVI).Furthermore, by preferentially selecting for the more dense bacteria, organisms such as GAO and PAO's are naturally selected for. This provides the opportunity to achieve BIO-P in the existing system for chemical free phosphorus removal.

EDI's IDEAL™ Lagoon System

The Intermittently Decanted Extended Aeration Lagoon, or IDEAL, consists of an EDI floating lateral aeration system with Magnum fine bubble diffusers, two chains of BioReef BioCurtain, a static decanter with flow control valves, an overflow pipe with Storm Mode™, process controls, and a blower package. The simple operation of the IDEAL provides easy, cost-effective operation while the sophistication of the design provides high levels of BOD, TSS and ammonia removal.

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