ExtremeDuty™ Sludge Mixer
ExtremeDuty: Vigorous Mixing of Anaerobic Digester Contents
For nearly 30 years, WesTech has been supplying mechanical sludge mixers for wastewater treatment plants. The current sludge mixer has evolved over the years as a result of WesTech striving to meet and exceed our customers’ needs.
WesTech ExtremeDuty™ Sludge Mixers provide vigorous mixing of digester contents to prevent stratification and improve the anaerobic digestion process. They reliably speed gas production while reducing foaming and scum accumulation.
This rugged design was originally developed to reduce the high service costs of egg-shaped digester mixers. It has proven to be so reliable that the ExtremeDuty Sludge Mixer is now used for maximum efficiency and durability in all WesTech digester mixing applications.
The stellar performance of the durable ExtremeDuty Sludge Mixer is proven in more than 700 installations, with an unprecedented full five-year warranty.

Benefits and Features
Features and Benefits
Unmatched five-year comprehensive warranty
- Includes parts, labor, and removal, if specified
Ragless reversible impeller
- Dynamically balanced three-blade cast iron impeller is self-cleaning
- Forward and reverse pumping re-entrains foam and settled solids
Bearing and seals
- Double-thrust and spherical roller bearings prevent wear
- Mechanical and double-lip seals ensure complete protection and increase abrasion resistance
Grease lubrication and spent return system
- Lowest volume of grease usage (less than 20 L/year)
- Low pressure system protects seals
- Low viscosity “triple aught” (000) grease is readily available for purchase
- Spent grease is returned to the top of the mixer (not wasted into tank), providing up-to-date information on the condition of the seals and bearings
Mixer housing
- Rigid design eliminates the need for stabilizers or centering devices
Impeller shaft
- Designed to avoid natural frequencies that cause vibration and minimize deflection
- Precise machine tolerances assure a quiet and smooth running system
Seal tube
- Designed to create a liquid seal so the mixer can be removed without releasing pressure or draining the digester
Design flexibility
- Internally mounted on the digester cover
- Externally mounted with supports on the ground and two holes through the tank