The STM-Aerotor

The STM-Aerotor is a highly effective addition to most wastewater treatment flow sheets. It combines aeration, Activated Sludge process and Fixed film process in one simple, yet ingenious tank. Mounted on a center shaft, hollow media capture air as the shaft turns, drawing it down into the bottom of the tank. The air is slowly released as coarse bubble aeration. Oxygen transfer efficiency compares favorably to coarse bubble aeration, but without the expense of running blowers or diffusers. Fixed Film growth on the media are in an ideal environment for nutrient removal, and stay optimally reactive due to the roiling waters of the tank. See the video below for a visual demonstration.

The unique STM-Aerotor design allows the process tank to develop anoxic and/or anaerobic zones within the same basin. By controlling the speed of the rotating wheel based on the dissolved oxygen residual or oxygen-reduction potential. The process control system can typically achieve total nitrogen below 2 mg/l. For enhanced biological nutrient removal, the STM-Aerotor system can be combined with additional biological selector zones in separate basins to achieve total nitrogen below 3 mg/l and total phosphorus below 1 mg/l. Effluent quality that is sought after, can be readily achieved with the STM-Aerotor from WesTech.

Stable Process Performance
High process stability and flexibility, even under high loadings, by combining the activated sludge and fixed film processes. Even the most strict effluent standards can be met consistently.

Solid and simple Construction
ISO Monitored Quality System assured construction, including long life polypropylene media, simple low maintenance drive train, nylon lined support bearings for extended life.

Lowest Capital Cost
Tank volume is reduced up to 40% versus conventional aeration.

Lowest Energy Usage
Power consumption is less than half that of a conventional activated sludge system, and only 40% of a comparable sequencing batch reactor.

Advanced Biological Nutrient Removal
The STM-Aerotor can provide consistent simultaneous nitrification/denitrification, as well as biological phosphorus removal, in a single basin.

No Noise or Odor Problems
Simple slow speed mechanism reduces operating noise. The STM-Aerotor process eliminates aerosol misting problems, and results in virtually no odors to annoy neighboring communities.

Improved Sludge Quality
Better Sludge settling characteristics (lower sludge volume index), better dewatering, and smaller volumes of waste sludge.

Many Applications
The STM-Aerotor is applicable to a wide variety of processes and industries. Petrochemical, Food Processing, Municipal Wastewater, anywhere where Aeration and BNR are required.

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