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Wastewater Treatment Plants For Larger Volume Systems 

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, also RV sites, sub-divisions, shopping malls, and other industrial or commercial applications.

Components are pre-assembled and installed into pre-fabricated Fiberglass Reinforced Plastic (FRP) tanks making the end product an essentially plug and play unit, with minimal on-site installation. Simply connect the sanitary sewer line to the inlet of the first chamber of the Sewage Treatment Plant, the outlet to the final discharge outlet.

The supplied aeration blowers are connected to the air inlet pipe on the tank, and the system is ready for operation. Maintenance is equally simple and is described in the O&M Manual.

The sewage treatment system utilizes the activated sludge - extended aeration process with fixed media, for a simple and robust design, which has proven reliable and will deliver high quality effluent.

Systems can also be configured for nitrogen removal and/or disinfection if required by your operating permit.

Typical equipment fitted into the FRP tank:

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


The Waste Water 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 for timer dose, to ensure equal volume is delivered 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 formation of Bio Film on the surface of the media, thereby increasing contact time which ensures process stability and sludge settle-ability.

The liquid / solids separation occurs in each compartment. Clear supernatant then leaves the WWTP. The treated effluent will then flow into the Pump Chamber (if part of the design), which will house the UV lamps (if required).

Click here to see some examples of our drawings.

Example of Model Numbers for larger Average Daily Flow (ADF) Waste Water Treatment Plants:

HOR600STP - 6,000 gals ADF
HOR900STP - 9,000 gals ADF
HOR1200STP - 12,000 gals ADF
HOR1500STP - 15,000 gals ADF
HOR2000STP - 20,000 gals ADF

The volumes in the above models are nominal, the size of treatment plants can be adapted to the required Average Daily Flow.

Access is provided to all compartments of the sewage treatment plant via 600mm or 762mm diameter access manways to facilitate maintenance. Risers are provided for at-grade access.

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