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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

More Contact Info

Questions and Answers


Q: What pollutants cannot be successfully treated at the Columbia Boulevard Wastewater Treatment Plant?
A: Toxics like pesticides, herbicides, antifreeze, gasoline and solvents like paint thinner. These types of "household hazardous wastes" can be recycled. You can learn more from Metro online or call Metro Recycling Information at 503-234-3000. 

Q: How is wastewater treated by industries before it leaves their facilities?
Many industrial facilities and businesses must pretreat their wastewater before releasing it into the sewer system or pouring it into storm drains. Some industries, such as dairies and pulp and paper plants, use the activated sludge process that is used in municipal wastewater treatment plants. Some use chemical treatment and filtration and recycle usable materials. Other industries concentrate toxics and transport them to hazardous waste sites. 

Q: Who pays for Portland's wastewater treatment system? How?
The users of the system including residents and industrial customers who discharge waste into the sewers. Residential customers pay sewer user fees which are included in their water bills. "Extra-strength" industrial customers are monitored and billed on separate acccounts. 

Q: How many gallons of wastewater does the average Portland customer produce?
It varies, depending on how much water a customer uses, other than watering plants or lawns. But on average, each customer generates about 100 gallons of wastewater each day. 

Q: What is the cost per gallon to treat Portland's wastewater?
The cost is about 1-cent per gallon for operating and maintenance costs. 

Q: What can people do to help maximize the efficiency of the Columbia Boulevard Wastewater Treatment Plant?
Keep fats, oils and grease (FOG) out of the sewer system. Pour grease into steel food cans, put them in the freezer and throw out with the trash. Keep toxic and nonbiodegradable substances, like plastics, out of the sewers and conserve water.