Gold Bar Wastewater Treatment Process 

At Gold Bar, solid, organic, and chemical waste is separated from wastewater so that it can be safely re-introduced into the ecosystem. Wastewater enters the plant from two large sewer channels, and then undergoes several treatment phases before it is ready to exit the plant and enter the North Saskatchewan River via the plant's main outfall pipes.

Gold Bar treats an average of 268 million litres per a day with a peak primary treatment design capacity of 910 million litres per day, and peak secondary/tertiary treatment capacity of 420 million litres per day. Note: 310 million litres per day is the plant's overall design capacity.

Pre-treatment

Large solid matter and grit is screened and removed from the raw wastewater. As it passes through the grit tanks, large rakes and screens separate the larger solids material (plastics, paper, rags, metal, grit, etc.) from the influent stream. This is necessary to prevent damage to equipment, and allow for the following treatment procedures to focus on removing the organic matter and pollutants.

Primary Treatment

Once all the grit and screened solids have been removed, the wastewater enters the primary clarifiers. It still contains a large amount of sludge and scum (partially-dissolved waste). In the deep clarifier tanks, the heavier sludge settles to the bottom while the scum rises to the top. Both sludge and scum are then scraped and skimmed off and piped away for separate treatment, while the primary effluent travels on to the next treatment phase. By the end of this process, approximately 50% of pollutants are already removed.

Secondary Treatment

The remaining approximate 50% of pollutant loading is more difficult to remove. Most of these solids will not settle out by gravity alone and therefore cannot simply be scraped out by rakes or machines.

However, rather than use chemicals to aid treatment, Gold Bar employs biological reactions to further clean the effluent. In the bioreactors, microorganisms are introduced into the primary effluent in ever greater number. As they continue to grow and multiply, these microorganisms feed on the dissolved organic matter and other pollutants, breaking them down.

The effluent is then sent to the secondary clarifiers. As in the primary clarifiers, gravity and mechanical rakes separate matter from the effluent. In this case, the microorganisms bind together as a 'floc', settle to the bottom and are separated by mechanical rakes. Most of this floc is channeled back into the bioreactors, while a small portion is removed and broken down with the rest of the solid waste. All solid waste is treated separately in fermenters or digesters. Again, no chemicals are used.

Tertiary Treatment

Modifications to the secondary bioreactors allow the microorganisms to perform the further task of removing even more impurities, namely the nutrients phosphorus and ammonia. Once these nutrients and the dissolved solids have been take care of, the clear final effluent is ready for disinfection. Disinfection occurs in the UV facility by exposure to high-intensity ultra-violet light.

The water is now treated and meets regulatory standards to be returned to the North Saskatchewan River via the plant's main outfall.