Alfa Laval - AS-H Iso-Disc

AS-H Iso-Disc

The high-performance cloth media filter captures solids to produce reuse-quality filtrate in a continuous operating process. The polishing filter is designed for tertiary filtration and final polishing in municipal and industrial wastewater treatment.

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Simple, efficient and flexible solution to your water filtration requirement

  • High-quality filtrate with California Title 22 Water Reuse Certification
  • Easy to operate with fully automatic filtration and uninterrupted operation during backwashing cycle
  • Easy to maintain due to individual filter element monitoring and maintenance
  • Small footprint-to-flow ratio
  • Robust design

The Alfa Laval Iso-Disc waste water filter is designed to fit your specific needs flexibly. The wastewater system can be easily expanded. Both square and rectangular cassettes fit within the path of the incoming water and are available to cater different installation configurations. It also allows for individual visual assessment of the effluent flow rate and quality.

Top performance

Performance of the Iso-Disc cloth media filter is second to none. The cloth media is capable of solids capture down to less than 10 microns. The pile cloth media allows for complete cleaning during backwash, utilizing filtered water from inside the filter plate.  If required, the cloth media can be replaced and the filter plate re-installed in a matter of minutes, all while the filter continues to function without interruption.

pile cloth filters for wastewater treatment
Iso Disc wastewater filter system filtrate discharge

The gravity driven, continuously operating filter uses completely submerged filter media, which gives 100% active filtration area all the time. The outside-to-inside flow through the pile cloth media provides much better depth filtration compared to screens. All internal or submerged components are corrosion-resistant stainless steel or non-metallic materials. For retrofits, the square or rectangular filter plates easily fit into existing basins and require only a low driving force of 30 cm water column.

Produce high-purity filtrate from applications such as tertiary filtration, process streams, surface water treatment and other water reuse as you handle solids and hydraulic loading with a small footprint-to-flow ratio.

How it works


Use of the fixed-filter media design reduces overall horsepower and permits removal of each individual filter plate while the filter remains in operation. During backwash, the filter plates remain fixed while the dynamic, bi-directional, linear backwash manifold serves as a header for removal of solids from the pile cloth media.

At the beginning of the backwash cycle, which is initiated by headloss across the filter, electrically actuated valves segregate the backwash header and clean the filter plates on that portion of the header. This ensures complete cleaning of the filter cloth while minimizing the rate at which backwash water is returned to the treatment facility.

The Iso-Disc cloth media filter can be installed into a concrete structure (supplied by others), pre-fabricated carbon steel with epoxy coating, or stainless steel tanks.

A unique advantage is incorporated into the Iso-Disc design that allows filtrate isolation and sampling from each filter plate individually, as well the ability to remove an entire filter plate from the system without filter shutdown. The design also eliminates rotating underwater seals thereby ensuring filtrate quality, while guaranteeing no cross-connection between influent and filtrate, and requiring less maintenance. 


Case Stories

Reclaimed wastewater save City of Meadows nearly $25,000 annually

"This lake changed our community and we are proud of the fact we are using reclaimed water. The success of the Iso-Disc filter has made all of this possible." Mayor Charles Jessup and Utility Director, Dan McGraw

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Keeping the Credit River clean

"The Iso-Disc filters are running well operationally and compliance wise, and they have reduced our maintenance significantly." Ashley Barrie, Supervisor, Wastewater Plant Operations, Region of Peel.

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