Odor Control --
Working in your neighborhood to protect public health and the environment

On this page: Being a good neighbor | A regional system | Odor control devices | News releases | More information Tips for reducing household sewer odors How to report sewer odor complaints

King County continues to do extensive research and pilot studies to test and develop cost-effective, cutting-edge odor technology. Improvements are being planned at both treatment plants and throughout our system.

Sometimes odor prevention solutions can be as simple as resealing a manhole cover. Other problems can be more complex.

The Wastewater Treatment Process. Click image for large version.

Some odors occur naturally, such as along beaches in the summer, and can’t be dealt with by any agency. Don't be discouraged. It will go away with cooler weather and rain.

Being a good neighbor

King County protects public health and the environment by treating 200 million gallons of wastewater every day. Being a good neighbor by controlling odors is a part of the normal operation of every treatment facility. We continuously monitor our existing treatment plants, pipeline network and pump stations for odor releases and we respond in the following ways:

• Add chemicals or biological enzymes at certain points in our pipeline network
  
• Install odor scrubbers using either wet chemicals or activated carbon in high-odor areas
  
• Chlorinate wastewater entering the treatment plant
  
• Continually explore solutions to odor issues
  
• Respond immediately to citizen complaints.

The Wastewater Treatment Division makes every effort to respond to odor complaints promptly and effectively.

A Regional System

The King County Wastewater Treatment Division protects public health and our regional waterways by safely transporting and treating wastewater from much of King, south Snohomish and parts of Pierce Counties. Two hundred seventy-five miles of pipes carry wastewater from areas as far north as Mill Creek, east as Black Diamond, west as Vashon Island, and south as Lake Tapps. Thirty-four local sewer districts within the wastewater service area own and operate local collection systems and send wastewater to King County's larger pipelines. Local agencies are responsible for billing residents for wastewater collection and treatment.

Sometimes, sewer odors may come from your local system, not the King County system. Each district is responsible for maintaining its system and controlling odors. Many King County sewer manholes have "METRO" on the lid. If you wish to identify which sewer agency serves you, look on your sewer bill. Call your agency if there are odors near your house.

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Odor Control Devices

Wet Chemical Scrubber–Foul air is forced through a “rain” of a chemical and water solution. The solution absorbs the odors.

Activated Carbon Scrubber–Foul air is forced through a bed of activated carbon granules. The granules absorb the odor.

Biological Treatment–Foul air is passed through a biologically active filter (or scrubber) where bacteria digest contaminants and neutralize odors.

Chemical Addition to the Wastewater Flow– Chemicals are added directly to the flow of wastewater, usually through a manhole at locations where odors have been troublesome. The chemicals reduce bacterial growth and neutralize odors.

Contained Facilities–Some processes at the treatment facilities are enclosed in buildings, and the air is scrubbed before it’s released into the environment.

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News releases

• News Release, July 14, 2003 - Council Approves Plan to Reduce Odors at Wastewater Treatment Facilities
• News Release, July 10, 2003 - Sims commends council committee for endorsing odor prevention policy for wastewater treatment
• This Week, June 9, 2003 - Work of Odor Control Task Force nothing to sniff at

For more information

• Odor Control brochure, (PDF file, 529KB)
• Odor Prevention Policy Recommendations, Regional Wastewater Services Plan, Odor Control Strategy, March 18, 2003 (PDF file, 2.5MB)
• Odor Control at the planned Brightwater Treatment Plant.
• Please contact Doug Marsano by e-mail or at 206-684-1235.

For questions about the Wastewater Treatment Division Web site, please send an e-mail message. For general information about the division, contact us at:

Department of Natural Resources and Parks
Wastewater Treatment Division
201 S. Jackson St., Suite 505
Seattle, WA 98104-3855
Phone: 206-684-1280
Fax: 206-684-1741
Telecommunication device for the deaf (TTY): 711

Updated: Dec. 7, 2006
 

Related Information:

Regional Wastewater Services Plan