Integrated Fixed-film Activated Sludge

Your challenge:


Meet ammonia, BOD, nitrate, or even phosphorus limits: You need your activated sludge-based wastewater treatment plant to consistently hit required total ammonia-nitrogen, cBOD₅, total nitrogen/nitrate, and phosphorus removal levels.

Increase the surface area available to attached-growth biomass: By growing treatment microorganisms as a fixed film on a surface, BioPorts minimizes the washout associated with suspended-growth biomass.

Keep footprint to a minimum: Real estate is at a premium, and a lack of aeration energy or oxygen isn’t always the limiting factor.

Our technology:

Nexom is the exclusive source for BioPorts™ Integrated Fixed-film Activated Sludge (IFAS). BioPorts combines concentrated attached-growth kinetics with Nexom’s unmatched biological treatment expertise to create an intensified nitrification, denitrification, BOD removal, and even biological phosphorus removal technology.

Why do you need a BioPorts system? BioPorts technology installed at your plant allows you to:

  • Customized, intensified biological nutrient removal (BNR) allows you to meet any or all of your BOD, ammonia, nitrogen, or phosphorus requirements.

  • Compact design allows your plant to do more within the basin you already have

  • Combination of superior components and process design expertise ensures your IFAS system is designed for your specific application and will work as intended.


  • Easy upgrade for activated sludge-based treatment plants
  • Handles high strength and/or highly-variable loading
  • Reduces clarifier loading
  • Media size optimized for large surface area while allowing for more coarse screening
  • Operational simplicity
  • Minimizes footprint
  • Nitrification for Total Ammonia-Nitrogen compliance
  • Denitrification for Total Nitrogen/nitrate compliance
  • BOD reduction
  • Enhanced biological phosphorus removal (EBPR)
  • Activated sludge plant upgrades
  • New IFAS installations

How it works

How it works

Retaining and oxygenating biomass to intensify treatment today and be ready for tomorrow.

Understanding the basics of how BioPorts™ IFAS works involves some of the same fundamentals underpinning the related moving bed biofilm reactor (MBBR) process.

Biomass is easiest to retain when it’s fixed to a surface. Whether the intent is to remove BOD, nitrify ammonia, or even denitrify nitrates, growing biomass on a surface minimizes the washout that occurs in a suspended-growth environment. BioPorts provides that surface area—and plenty of it—in the form of dynamic media that is submerged and contained in a tank.

While the biofilm is fixed on the media, the media itself circulates in the tank. The integrated aeration in the tank not only ensures high dissolved-oxygen levels throughout, it also moves the media within the tank, enabling a more even distribution of loading and oxygenation to the biomass.

As a result, BioPorts™ IFAS can accommodate rapid increases in loading or flows. Because there is ample surface area for biomass expansion and basin mixing effectively distributes the biofilm-laden media, loading and oxygen throughout, BioPorts IFAS installations are able to address high strength or highly-variable loading more effectively than traditional activated sludge basins.

A BioPorts IFAS system also reduces loading to your clarifiers. Because the BioPorts media retain more of the treatment biomass in the basin, your IFAS system can treat substantially more BOD or nutrients, while contributing less mixed liquor suspended solids (MLSS) loading to clarifiers.

Flow enters the fully-aerated tank and encounters the biofilm-coated media. Coarse effluent screens prevent the patented BioPorts media from leaving the tank. Depending on the configuration, multiple tanks in series can be used to meet low effluent requirements and/or address several different contaminants and nutrients.

BioPorts Components

BioPorts Media: 600-14

Media Design
Biofilm coverage
US Metric
Outer diameter 0.70 in 18 mm
Cylinder length 0.55 in 14 mm
Biologically-active surface area 179 ft²/ft³ 589 m²/m³
Material High-density polyethylene (HDPE) with carbon black added for UV protection
Specific gravity 0.96
Max aerobic fill capacity 67%
Max anoxic/anaerobic fill capacity 50%

BioPorts Media: 900-09

Media Design
Biofilm coverage
US Metric
Outer diameter 0.67-0.78 in 17-20 mm
Cylinder length 0.35 in 9 mm
Biologically-active surface area 287 ft²/ft³ 942 m²/m³
Material High-density polyethylene (HDPE) with carbon black added for UV protection
Specific gravity 0.96
Maximum aerobic fill capacity 67%
Maximum anoxic/anaerobic fill capacity 50%

Media Screens

BioPorts media retention screens are fine enough to keep the biofilm-carrying media from escaping the basin, but coarse enough to allow particulates to pass through and prevent the screen from fouling or blinding.

Media screens can also be arranged in parallel to better accommodate variable flows. Vertical screens with above-surface access ports can be used to enable better access for effluent sampling or occasional screen maintenance.

Fixed grid aeration

Thanks to the integration of Nexom and EDI, our aeration capabilities are the envy of the industry. Most BioPorts facilities are designed with EDI fixed grid aeration within our basins to optimize performance with minimal O&M.

In fact, based on that aeration expertise, Leeds, Alabama's BioPorts MBBR is able to achieve optimized mixing and oxygen-transfer with ~25% of the energy typically required.

What it Delivers

IFAS transforms maricopa County, AZ treatment facility

The BioPorts™ process is the best choice for roughing high influent BOD, polishing ammonia, or upgrading to IFAS. In place at dozens of installations across North America, BioPorts MBBRs or IFAS installations deliver as promised and ensure that operators sleep well at night knowing they have the system in place to beat their BOD and nutrient limits.

Want to know what BioPorts could do for your system?

Submit your RFP today and our on-staff professional engineers can help you size and design a BioPorts MBBR to meet your wastewater treatment requirements.



There are many factors which can influence the cost of a BioPorts system, including design flows, loading, treatment requirements, and existing infrastructure. The best way to determine the cost for your specific application is to submit your RFP to our project development team.


Based on its small footprint design and modular scalability, BioPorts is among the most simple wastewater treatment solutions to upgrade, whether your focus is further nitrification or BOD removal, denitrification to meet Total Nitrogen limits, or beyond.


Almost never. The media is sized so that it can be retained by coarse effluent screens for no downstream media loss, and it is built from durable HDPE that means the BioPorts media that you start with should last the life of your installation.

Have a question that wasn’t answered here?

Contact one of our product specialists (or your local Nexom rep) and we’d be happy to answer it.