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Large Volume Sewage Treatment Plants: Above 5000 Igal/Day Flow

STP Off-Loaded On-Site

Canwest Tanks offers individually designed large volume sewage treatment plants ranging from 5,000 Igal (22m³/day) to 100,000 Igal (450m³/day). The sewage treatment plants are designed, reviewed, and sealed by a Professional Engineer (P. Eng.) for each application.

Sewage treatment plants can be designed for work camps in remote areas, taking into consideration the specific site conditions as well as RV sites, sub-divisions, malls, and other industrial or commercial applications.

Components are pre-assembled and installed into pre-fabricated fiberglass reinforced plastic (FRP) tanks to facilitate ease of installation. The end product is essentially plug and play with minimal on-site installation. Simply connect the sanitary sewer line to the inlet of the sewage treatment plant, the outlet to the final pump chamber, and the factory supplied aeration blowers to the factory supplied air inlet.

The sewage treatment plants utilize the activated sludge extended aeration process with fixed media, for a simple and robust design, which is reliable and delivers high quality effluent.

Systems can also be configured for nitrogen removal and/or disinfection if required

by your operating permit.

Typical features include:

  • Trash tank or primary clarifier
  • Flow equalization
  • Sludge storage tank
  • Sludge return
  • Reactor chambers connected by “plug flow” to improve mixing
  • Pump chamber if required

Plug Flow System

The wastewater treatment plant (WWTP) utilizes the activated sludge extended aeration process and submerged media. Primary clarification and flow equalization is provided; disinfection using ultra-violet light radiation may also be part of the process but depends on the effluent quality demand, whether it is compliant with Class B or Class C effluent.


Raw wastewater enters the primary clarifier via a gravity sewer. Wastewater is then hydraulically displaced into the flow equalization tank. The flow equalization tank has been designed to store surges in flows into the plant and top release them to the WWTP uniformly over a 24-hour period. The duplex pumps are set on a timer to ensure equal discharge to the WWTP in any one hour. Excess influent is retained or stored in the flow equalization tank and released at a needed rate per hour. This ensures that the WWTP receives influent uniformly over a 24-hour period and safeguards against washout. Wastewater is hydraulically displaced through each of the compartments connected in series before passing through the submerged media. The fixed media is designed to promote colonization of microorganisms on the surface of the media, thereby increasing process stability and sludge settle-ability. Liquid solids separation occurs in each compartment. Clear supernatant then leaves the WWTP and flows into the pump chamber, which will house the UV lamps if this is part of the design.

Access is provided to all compartments of the sewage treatment plant via 600mm diameter access manways to facilitate maintenance. Risers are provided for at-grade access.

Canwest Tanks offers full installation and commissioning support as well as operator training.

Click here to see some examples of our drawings.

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