AccuFAS® Submerged Fixed-Film System Components

Brentwood’s AccuFAS system consists of a series of individual bio-reactors integrated with aeration, support, and restraint components. These reactors are built from individual blocks of media which are cross-stacked to form towers within the aeration basin. The construction of these discrete reactors involves erecting a pre-engineered support system, AccuPier®, over a diffuser grid with restraints that ensure the towers remain fixed in place.

Brentwood bio-accufas System Components

The unique tower design of distribution and vertical flow media, as well as proper spacing of towers within the tank, complement the aeration system to distribute liquid and airflow evenly and allow continuous mixing and scouring. Airlift pumping generated by the diffusers provides excellent mixing, which allows for a thin and effective biofilm layer to be maintained on the media. With lightweight, easy-to-install media that promises a 20-year service life, the robust design of AccuFAS will provide efficient treatment results with minimal system maintenance and no need to replace worn, abraded, or lost media.

Structured Sheet Media

Brentwood’s unique AccuFAS tower designs consist of vertical flow and distribution media, installed in layers for even distribution of air and liquid to allow for continuous mixing and scouring of biofilm.

Structured sheet media has been successful in trickling filter applications since the late 1950s because of its proven longevity, simple installation and operation, and improved stability for biological treatment processes. Capitalizing on experience with over 500 structured-sheet media installations in trickling filters worldwide, Brentwood developed a media structure specifically for submerged applications.

AccuFAS media maximizes air distribution much in the same way that trickling filter media maximizes wastewater distribution. Individual media blocks, consisting of corrugated polyvinyl chloride (PVC) sheets solvent-welded into modules, are cross-stacked to build AccuFAS media towers within aeration basins. The unique tower design combining distribution and vertical flow media evenly distributes liquid and air to allow for continuous mixing and scouring. All Brentwood structured sheet media is fabricated from rigid, self-extinguishing, UV-protected PVC that is resistant to rot, fungi, bacteria, acids, and alkalis commonly found in wastewater.

Supports and Restraints

  • Accupier Support System – A pre-engineered support system for structured-sheet media, AccuPier is a lightweight and robust system that includes field-adjustable bases and cut-to-length stanchions to allow for installation in a variety of tank configurations.

  • Media Restraints – Designed to keep submerged film media in place during operation, restraints are engineered to integrate with AccuPier support components.


  • Aeration Diffusers – The easily maintained aeration system uses cost-effective diffusers mounted under the media towers to provide a high level of oxygen transfer efficiency and to circulate the wastewater by airlift pumping.

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