Plant Improvements at Salem's Geren Island Water Treatment Facility

Salem invested over $50 million for the design and construction of a state-of-the art ozone treatment facility at Geren Island to ensure our community has safe and resilient drinking water long into the future.

Benefits of Ozone

• Ozone treatment offers many benefits:
• Destroys cyanotoxins
• Makes it easier to ensure safe drinking water
• Works well with the other treatment steps on Geren Island
• Produces good tasting water, year-round
• Reduces how much chlorine is needed
• No ozone is left in the water after it has done its job

How Ozone Works

Step 1: Oxygen Supply

Ozone (O3) is made from oxygen (O2). We are using super-cooled liquid oxygen. The liquid oxygen is first warmed and converted to oxygen gas. The oxygen gas is then sent to an "ozone generator."

Step 2: Ozone Generation

The ozone generator uses an electric charge to turn oxygen gas (O2) into ozone gas (O3). Once formed, ozone gas moves to a "contactor" chamber where it dissolves into and begins to clean our drinking water.

Step 3: Ozone Injection and Contactor

In the contactor chamber, ozone gas (O3) dissolves into the water. Here, it destroys cyanotoxins (if they are there) and breaks down any remaining materials that may affect the taste or smell of the water.

Step 4: Dissolved Ozone

Under normal operating conditions all of the dissolved ozone is used in the treatment process. If all the dissolved ozone (O3) isn't used up, it will go through a process to turn it back into oxygen gas (O2) before it is discharged back into the atmosphere.

Integrating Ozone into the Existing Geren Island Water Treatment Plant

We have a multi-step approach to destroying cyanotoxins. The ozone contact chamber will be located downstream of the existing roughing filter. The roughing filter removes cyanobacteria (the primary source of cyanotoxins). Any remaining cyanotoxins will be destroyed by ozone treatment. Water will then be cleaned in the slow sand filters and chlorinated.

Ensuring a Safe and Sustainable Water Supply

We are investing in a groundwater system on the Geren Island Water Treatment Plant. Groundwater wells can provide another source of water that is protected from cyanobacteria and storm events that impact the North Santiam River.

Long-Term Solution for Removing Cyanotoxins

The City of Salem will use the new ozone treatment system to remove cyanotoxins. Ozone is one of the strongest disinfectants used to treat water – it is even stronger than chlorine. Ozone also makes our water crystal clear, improves the taste, and can remove odors. Once in operation in spring 2021, ozone will be our robust, long-term insurance policy against cyanotoxins.