Joint Utilities Sewage Lagoons Treatment Plant


South End Sewer Area West Map [PDF - 720 KB]
South End Sewer Area East Map [PDF - 522 KB]

Wastewater is pumped to the Inlet Works Facility where large particles are removed by a mechanical screen. In addition, grit is removed in settling channels.

The wastewater is then piped to a completely mixed and aerated lagoon cell where it is mixed with micro organisms. The micro organisms consume the organics producing more micro organisms.

The treated wastewater is then piped to three settling cells arranged in series. The micro organisms settle to the bottom of the settling cells. The treated wastewater, less the micro organisms, flow to the disinfection systems’ contact cells.

If additional treatment is required the first two of the three settling cells have floating aerators that can be turned to increase the treatment capacity of the facility. Normally this is not required.

The treated wastewater that has flowed to the disinfection cells is chlorinated at the beginning of the first disinfection cell to kill any germs that may be present.

The disinfected effluent is then de-chlorinated at the end of the second disinfection cell to remove any chlorine that is left in the effluent before it is released to the outfall in the Cowichan River.

In 2002/2003, a new phosphorus removal system was constructed at a cost of $270,000 to reduce the amount of phosphorus that will be discharged to the Cowichan River.  Phosphorus is typically reduced from an average of 4.5 ppm to less than 1 ppm.

  • Cost - $3.9 million dollars
  • Population Served in 1998 - 20,500
  • Design Flow Capacity - 31,400
  • Design Flow Capacity - 17,280 cubic metres per day
  • Treatment Process - One Complete Mix Aerated Lagoon, Two Facultative Lagoons / Part Mix Aerated Lagoons, One Settling Pond, Chlorine Disinfection & Dechlorination
  • Funded - Municipal
  • Consultants - Delcan (Civil / Environmental) and Shaflik Engineering (Electrical)
  • Contractor - C-1 Construction
  • Commissioned - March 2000