KWS Manufacturing

Pivoting Shaftless Screw Conveyor for Biosolids Load Out Tsawwassen First Nation Sewage Treatment Plant

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End User or Owner

Tsawwassen First Nation SSTP DB
Tsawwassen, BC

Consulting Engineer

Associated Engineering
Toronto, Ontario


Maple Reinders, Inc.
Langley, BC

Plant Name and Location

Tsawwassen First Nation SSTP DB
Tsawwassen, BC

General Description

The Tsawwassen First Nation is a First Nations government whose lands are located in the Greater Vancouver area of the Lower Mainland of British Columbia, Canada, just north of the international boundary with the United States at Point Roberts, Washington. A new wastewater treatment plant was constructed through a design-build contract with Maple Reinders Inc., one of Canada’s leading design/build contractors. The plant comprises a sequence batch reactor system with tertiary treatment capability. The plant will be developed in phases and will eventually have sufficient capacity to service all Tsawwassen Lands.

KWS Environmental provided a shaftless screw conveyor system to receive dewatered biosolids from a centrifuge located on the floor above the loading area and evenly distribute it to one of two loading bay dumpsters. A low cost, reliable system to load through two loading bays was required and KWS provided a unique solution.

Design Parameters

  1. Material: Dewatered Biosolids
  2. Solids Content: 23-percent by weight
  3. Material Density: 0.88 to 1.04-Kg per Cubic Meter (55 to 65-Lbs. per Cubic Foot)
  4. Maximum Design Capacity: 2.7 to 4.5-Metric Tons per Hour (91 to 180-Cubic Feet per Hour)
  5. Duty: 24 Hours per Day, 7 Days per Week

KWS Advantages

KWS provided a fully engineered system including mechanical, controls and instrumentation design. All KWS equipment is manufactured in the United States which allowed KWS to easily meet the delivery requirements of the project. Project management and startup services were also available at a moment’s notice. KWS offered a unique yet proven design utilizing a self-supporting, pivoting shaftless screw conveyor to distribute biosolids into dumpsters. The design eliminates the need for multiple conveyors, slide gates and sophisticated controls to distribute biosolids cake evenly into the load out containers.

Maple Reinders and the Owner were impressed with the ability of KWS to provide a complete package including a shaftless screw conveyor, supports, controls and after-sales service.

Special Features

The self-supported, pivoting shaftless screw conveyor is a unique design developed by KWS Environmental for loading biosolids into trucks or dumpsters. The design has been proven with many installations in North America. The equipment was designed and certified for a high seismic activity zone. The conveyor load out system controls were integrated with the centrifuge panel to allow automatic loading of dumpsters. Minimal operator attention is required during normal operation with very low maintenance. These features were important to the Tsawwassen community since they have limited experience with solids handling equipment.


"The equipment was easy to install and we appreciated the participation of KWS during interface coordination meetings. This helps ensure everything worked as planned."

Patrick Hamlin, Project Manager – Maple Reinders

Biosolids / Sludge

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