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How Does Vancouver Wastewater System Work

How Does Vancouver Treat Its Sewage?

Cities all over the world are struggling with how to treat their sewage. As cities grow, the amount of sewage they produce grows with it.

In most cases, discharging untreated sewage into rivers and oceans can lead to environmental disasters and public health crises. There are a lot of different ways to treat sewage, and each city has to find the best solution for its own situation.

In this article, we will discuss how Vancouver treats its sewage and what are the benefits and drawbacks of its system. Before we get into that, let’s first understand where does the sewage go in Vancouver.

Where Does The Sewage Go In Vancouver?

wastewater to sewerline

Vancouver’s population has been growing steadily for years, and as a result, the amount of sewage produced by the city has also been increasing. In Metro Vancouver, there are about 440 billion liters of wastewater (or sewage) treated every year.

This sewage comes from households, industry, and stormwater runoff. Then, collect it through a network of pipes or sewers and then transport it to one of Metro Vancouver’s five wastewater treatment plants. These are:

Four of these sewage water treatment plants treat the wastewater in two ways, the primary treatment, and the secondary treatment. The oldest water treatment plant is the Iona Island Wastewater Treatment Plant which uses the most basic and oldest sewage treatment technology and only the primary treatment. 

Iona Island Wastewater Treatment Plant
Photo: Iona Island Wastewater Treatment Plant

After Iona Island Wastewater Treatment Plant primarily treats the sewage water, they discharge the wastewater into the Georgia Strait (Mouth of the Fraser River). Georgia Strait is an ecologically sensitive river which makes this process dangerous for the environment. However, the program to upgrade Iona Island Wastewater Treatment Plant is ongoing and will be fully operational with both the primary and secondary treatment before 2030.

The other four sewage water treatment plants, Annacis Island, Lions Gate, Lulu Island, and Northwest Langley, use both primary and secondary treatment before discharging the treated wastewater into the environment. This means that the treated wastewater is much cleaner and poses less risk to the environment, people’s health, and aquatic life.

Why Do We Need to Treat Waste Water?

Untreated sewage can contain harmful pathogens that may cause disease if ingested or come into contact with skin. Treating the sewage before discharging it into the environment helps to protect human health and the quality of receiving waters, such as lakes and rivers.

In Vancouver, residents are fortunate to have a modern wastewater treatment system that uses a combination of physical, chemical, and biological processes to remove pollutants from our sewage.

The only drawback to this system is that it requires a lot of energy and money to operate, which is why it is important to do your part to help the environment by minimizing your water consumption and disposing of household hazardous waste properly.

What are the Wastewater Treatments?

Wastewater Treatment Plant

As mentioned above, there are two most common types of sewage treatment, primary and secondary. However, there’s also a more advanced treatment which is called tertiary treatment. Let’s discuss each one in more detail.

Primary Treatment

The first step in primary treatment is to remove large objects from the wastewater, such as sticks, leaves, and rocks. The treatment plant performs this process by letting the sewage water flow through a screen.

After that, the sewage water settles in a large tank for a period of time. During this time, the heavier solids (such as sand and grit) will settle to the bottom of the tank, while the lighter ones (such as grease and oil) will float to the top. Then discharging the wastewater from the tank, removing solid waste, and sent to a landfill.

Secondary Treatment

After primary treatment, the sewage water goes into the secondary treatment tank. In this tank, the sewage water is mixed with bacteria that break down the organic matter in the sewage water. The sewage water is constantly mixed and aerated to ensure that the bacteria have enough oxygen to do their job.

After secondary treatment, the sewage water is sent out into the environment, usually a river or the ocean.

Tertiary Treatment

In some cases, the sewage water undergoes tertiary treatment before discharging into the environment. Tertiary treatment is a more advanced form of sewage treatment that removes chemicals and organic matter from the sewage water. This treatment can remove 99% of the contaminants in the sewage water.

This type of treatment is usually only done when the sewage water from secondary treatment is going to be used for a specific purpose, such as irrigation or industrial uses. Vancouver’s government aims to upgrade all of its sewage water treatment plants to provide tertiary treatment in the near future. With tertiary treatment, the sewage water is much cleaner and poses less of a risk to the environment.

Does Vancouver Have A Combined Sewer System?

Yes, Vancouver does have a combined sewer system. In a combined sewer system, both stormwater and sewage flow through the same pipes to the treatment plant. During dry weather, the system treats and discharges wastewater into the environment.

However, during periods of heavy rainfall or snowmelt, the volume of water flowing through the sewer system can exceed the treatment plant’s capacity. When this happens, the treatment plant discharges wastewater directly into the environment without treating it.

The City of Vancouver is monitoring and working on upgrading its sewer system so that it can handle more water during periods of heavy rainfall or snowmelt. By upgrading the sewer system, the city can efficiently cure and discharge wastewater into the rivers or ocean.

Does Vancouver Dump Raw Sewage In The Ocean?

Step by step process of how wastewater (sewage) is treated for disposal

No, Vancouver does not dump raw sewage in the ocean. The city has a state-of-the-art wastewater treatment system that treats all of the sewage before discharging it into the environment.

In some cases, during periods of heavy rainfall or snowmelt, the treatment plant may be bypassed, and untreated wastewater may be discharged into the ocean. However, the city is working on upgrading its sewer system to reduce the number of times this happens.

What Are The Benefits Of Vancouver’s Wastewater Treatment?

There are many benefits of Vancouver’s wastewater treatment system. By treating the sewage before discharging it into the environment, the city is able to protect local waterways and the ocean from pollution.

The city’s treatment system also helps to keep the local environment clean and healthy. By removing contaminants from the sewage water, the treatment system helps to improve the quality of the water in rivers and oceans. This, in turn, benefits the plant and animal life that rely on these bodies of water for their survival.


Vancouver puts a lot of effort into keeping its sewage clean and safe, both for the environment and for the people who live there. Vancouver’s sewage treatment system is one of the most advanced in the world, and it is constantly being improved.

The city is always looking for new ways to make its sewage treatment more effective and efficient and to protect the environment. We also need to do our part to keep our sewage clean and safe. We can all help by using less water, disposing of waste properly, and not dumping anything down the drain that could harm the treatment process.

John Relampago

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