PWTech Sludge Dewatering and Thickening

PWTech® Volute Dewatering & Thickening Press

Envirep/TLC is the exclusive manufacturer's rep for PWTech® dewatering and thickening volute dewatering presses in Pennsylvania, New Jersey, Delaware, Maryland, Virginia, and West Virginia.

About PWTech®

Process Wastewater Technologies (PWTech) is a leading manufacturer of sludge dewatering and thickening technologies and combined sewer overflow (CSO) and sanitary sewer overflow (SSO) products located in Baltimore, MD. The Volute™ Dewatering Press is an innovative sludge dewatering device that offers many advantages over other dewatering devices such as belt filter presses, centrifuges, and traditional screw presses. The key to the process is the unique dewatering drum design that dewaters the sludge in a single, compact operation. The Volute™ Press is similar to a traditional screw press with a significant improvement. Traditional screw presses use a screw inside a perforated drum screen that needs to be shut down frequently and be cleaned by the operator using a pressure washer. The PWTech® Volute™ Press uses both fixed and moving rings instead of screens. The sliding of these rings next to each other keeps sludge from clogging the narrow spaces between the rings. Therefore, head loss does not build up, and the screen does not need pressure washed by the operator.


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  • Very low power consumption
  • Highly effective dewatering with high cake solids, low capture rates, and low polymer consumption
  • Minimum operator attention
  • Low maintenance costs
  • Fully automated capable of starting up, operating, and shutting down
  • Enclosed to minimize odors and noise
  • Easy to operate and maintain
  • Very low wash water usage


The Volute™ Press has a smaller footprint than other technologies, allowing it to be installed in places that are not possible with other dewatering technologies due to low ceilings or limited footprint area. Therefore, the construction cost of a larger building for installation is not required.


The PWTech® Volute™ Dewatering Press is used for a wide range of sludges:

  • Municipal wastewater treatment sludges including primary, waste activated (WAS), fixed-film, MBR, undigested, aerobic, and anaerobic digested
  • Potable water sludges, including alum, ferric, and powdered activated carbon (PAC) sludges
  • Paper mills and textile processing
  • Chemical manufacturing plants
  • Food and beverage manufacturing
  • Landfill leachate treatment


The Volute™ Dewatering Press is fully automated and capable of starting up, operating, and shutting down without operator interaction. The control panel with a programmable logic controller regulates sludge wasting from the wastewater process, clarifier, digester, or thickener. The fully automated dewatering process includes the flow meter, polymer feed system, mixing, flocculation, dewatering, and discharge conveyors. All components of the dewatering system work together, automatically starting up, operating, and shutting down as needed.


Pilot testing plays a crucial role in selecting and optimizing the sludge dewatering equipment. Every type of sludge requires a different approach since each sludge is unique in its composition and properties that influence the performance of the dewatering equipment. Pilot testing of the dewatering equipment confirms that the equipment will work properly with the specific sludge. It also allows the dewatering process to be optimized and provides essential data, including the expected throughput, cake solids, polymer consumption, and capture rate.

Pilot testing also provides the opportunity for training the plant staff in the operation of the equipment.

PWTech® offers pilot testing with full-sized Volute™ thickening and dewatering presses to successfully demonstrate the dewatering performance at your facility. The pilot test trailers include all the equipment needed for the testing, including the sludge feed pump, polymer feed system, flow meter, and PLC-based control system.

Please contact Envirep/TLC if you would like more information on the Volute™ press or if you would like to set up a pilot test.


PWTech® provides excellent service after the sale, providing optimal, long-term, trouble-free operation of your equipment for many years. Please inquire with any questions, such as how to operate, check and maintain equipment.



Our team at Envirep/TLC is well versed in all fields of water and wastewater systems. We can help you select the right thickening and dewatering equipment based on your requirements. Talk to one of our engineering experts today at 717-761-7884 or email us at


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