The STM-Aerotor™ combines activated sludge and fixed film in a compact biological treatment system that requires a low power input. The unique media of the STM-Aerotor provides both the fixed film surface area and the vehicle for coarse bubble aeration. The STM-Aerotor design allows for efficient aeration without the need for diffusers, air piping, control valves, diffused aeration blowers, or supplementary mixers.

IFAS process systems have been employed for wastewater treatment because they have many distinct advantages.  First, the IFAS process can accomplish more treatment than conventional activated sludge in an existing footprint.  Second, complete nitrification occurs at much lower sludge ages than conventional activated sludge plants.  Finally, the improvement in sludge settling makes operation of an IFAS plant much easier.  Most IFAS systems use a free-floating or structurally supported media in a diffused aeration basin, but the STM-Aerotor does not.  The STM-Aerotor has all the advantages of the IFAS process without the need for energy intensive diffused aeration or mixing equipment.

The STM-Aerotor™ has been used in different applications throughout the world.  The compact nature of this system works well for small package plants in new communities, resorts, campgrounds, and truck stops.  The ability to handle variable loading rates works well for industrial plants such as wineries, food processing, refineries, and dairies.  The modular design works well for small treatment plants (less than 5 mgd) that may expand or require nutrient removal in the future.

Advantages
• Low energy requirement
• Small footprint
• Improved sludge settling
• Stable process
• No odors