Wastewater Treatment Plant



The Resort Municipality of Whistler wastewater treatment improvements were first constructed in 1976. By 1984, more stringent provincial standards and increased flow demanded upgrading of the existing liquid handling facilities. In the 1990's due to the explosion of growth in the Whistler area (the highest in Canada in recent census), plant expansion was again mandated to ensure the discharge standards are met.

With completion of the latest expansion in 1997, the Whistler Wastewater Treatment Plant is equipped with an influent pumping station, headworks, and primary and secondary clarification systems capable of 52,000 bed unit capacity. The biological and solids handling systems are capable of 42,000 bed unit capacity.

The last three expansions were designed by Dayton & Knight, Consulting Engineers.

The plant SCADA system provides the WWTP with an automated control system and process monitoring and data aquisition. Some 300 I/O points are linked to the SCADA system. These include analog system providing real time measurements of such parameters as plant flows, pump speeds, tank levels, and process temperatures. The SCADA system incorporates the linking of 4 PLC's and 4 computer workstations using a fibre optic hub system. In addition, local and remote acess to the SCADA system is provided along with an alarm paging system for plant alarms outside of normal hours.

The Resort Municipality of Whistler operates one of the most advanced wastewater treatment facilities in British Columbia. The process includes primary, secondary and tertiary treatment using ferrous chloride for phosphorus removal. The treated wastewater meets all the requirements of the Ministry of Environment including receiving water standards for recreational use.

Liquid Flow

Wastewater from the RMOW trunk sewer enters the influent pump station. Pickle liquor is added to the wet well to aid in the settling and removal of phosphorus. Three 80 hp pumps lift the wstewater to the headworks area. Mechanical bar screens them, removes rags, plastics and other debris and grit separators remove the grit from the wastewater.

(Photo - Headworks)

The wastewater flow passes through the primary sedimentation tanks where heavy particles sink and are raked to the sludge sumps for removal to the ATAD digesters. Floating lighter materials are skimmed off and discharged to a skimming tank for disposal.
The wastewater is then distributed over the plastic media in the trickling filter. Here dissolved organics are absorbed onto the growing biomass. Excess sloughed off biomass and the liquid wastewater are then pumped to the solids contact tanks.

The cloudy trickling flilter effluent is mixed in the solids contact tanks with return biological solids from the secondary clarifiers. The contact occurs for 10 to 20 minutes before settling is again provided in the clarifier. A portion of the settled solids are returned to the solid contact tanks to be remixed with the trickling fliter effluent, with the rest wasted to the front of the plant to be removed with the primary solids.

The secondary clarifier effluent is then dosed with chlorine and contacted in the chlorine contact tank for 60 minutes to ensure disinfection. Sulphur dioxide is injected at the tank discharge to remove all free chlorine. The treated wastewater is then discharged to the outfall in the Cheakamus River.

Solids Flow

The Whistler Wastewater Treatment Plant uses the state of the art autothermal thermophilic digestion process (ATAD) for solids stabilization. This process produces a high grade retail use biosolids which meets EPA 503 standards.

The primary and waste biological solids from the primary sedimentation tanks are pumped to the ATAD for digestion and high temperature pasteurization. Treatment is coordinated in the four ATAD digesters. Solids are volatilized by over 50% at temperatures above 55C, producing a thin brown slurry of high nutrient value and minerals.



(Photo - Belt Filter Press)

The digested solids are then cooled and dewatered to a dry cake by the 2-metre belt filter press. The dewatered solids are then used for topsoil production, forest application or for cover material at the landfill. In winter, the biosoleds are stored in a covered building for later use in the summer season.








(Photo - Dry Cake)


The Whistler Wastewater Treatment Plant is classified as a Level IV plant.

Thanks to David Sivyer of the Whistler Wastewater Treatment Plant. If you would like to submit a profile of your operations - water or wastewater, please contact the EOCP. It's your chance for a free EOCP cap!




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