Visit us online at www.discoverycwa.org

Salmon Creek Treatment Plant Improvements Project

Fact Sheet – June 2018

The treatment plant is a vital part of the wastewater system—safeguarding public health, environmental quality and our community’s economic future. This project will provide for a planned increase in treatment capacity and improve odor control and operational reliability for the facility.

Project OverviewThe Salmon Creek Wastewater Treatment Plant receives and treats roughly 8–10 million gallons of wastewater per day from homes and businesses. All wastewater received at the plant is treated to a high standard before clean water, or effluent, is conveyed and discharged into the Columbia River.

As our community grows, we will need to expand the plant’s capacity to meet the increasing flow of wastewater. Improvements will also be made to the odor control systems and several areas of the in-plant mechanical systems to keep the facility current with regulatory requirements and in good working order.

Increase in Treatment CapacityThe Alliance will expand the biological treatment process to increase the plant’s treatment capacity from approximately 15 million gallons per day to 17.5 million gallons per day within the existing facility footprint. This will be accomplished by constructing a new Aeration Basin and Secondary Clarifier in the middle portion of the plant. Some older structures will need to be demolished to make space for these new facilities. In addition to these new structures, improvements to several mechanical pumping and air supply systems will be made inside existing buildings.

Odor ControlThese improvements will also include installing a new odor control system, which involves collecting air from the first two treatment processes and adding biotrickling filters that treat the air. These methods have proven very effective in reducing odors. In order to help collect the air, aluminum covers will be added over the Primary Clarifiers.

The Discovery Clean Water Alliance is a regional partnership made up of Clark County, Clark Regional Wastewater District, and the Cities of Battle Ground and Ridgefield. It was formed in 2013 to improve sewer service delivery to the partners’ customer bases by leveraging existing resources, controlling future capital costs, and stabilizing rates. The Alliance brings operation and expansion of treatment and transmission services under joint ownership, allowing for shared decision-making between the partners and better long-term regional planning.

For more information about the Alliance, visit the website at: www.discoverycwa.org

About the Alliance

Project benefitsThe project will:

• Effectively expand wastewater capacity to meet planned growth within the community, consistent with the long-term master plan for the site.

• Increase plant capacity while reducing impact to the surrounding area and without increasing the overall footprint of the plant.

• Construct a new odor control system that will continue to comply with air emissions regulations and improve quality of life for neighbors.

• Ensure continued reliable service at a stable, affordable rate.

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Odor Control: Clarifier CoversThe Primary Clarifiers, which remove solid waste and other objects from the wastewater, will get new aluminum covers similar to the photo shown to the right. These coverings will reduce the escape of odors that periodically emit from these areas.

Increased Capacity: New Aeration BasinA new aeration basin will be added to provide more capacity for adding oxygen to bacteria that are treating and stabilizing the wastewater. The new basin will be built on the site of the existing secondary clarifier, which will be demolished.

Increased Capacity: Larger Secondary ClarifierA new 120 foot diameter secondary clarifier will be built to support the new aeration basin, providing more capacity for secondary treatment. A small building will be demolished to allow the new clarifier to be built within the existing plant footprint.

Salmon Creek Treatment Plant Improvements Planning for the FutureIt’s important to plan for the future. Our personal health, the community’s economic health, and the health of our rivers and environment depend in large part on treating the wastewater we all generate so that it can be returned safely to the environment. As our community grows, we continue to make investments to ensure our system adequately meets our needs.

The Salmon Creek Treatment Plant Improvements Project is part of the Phase 5 expansion program, a planned future investment which will build on four previous expansions over the past 40 years. The Phase 5 expansion will take place over several years and will be performed as two separate and independent projects. In addition to this project, Phase 5 also includes the Columbia River Outfall and Effluent Pipeline Project, which will add a new transmission pipe and discharge mechanism from the plant to the Columbia River. You can read more about how this project will improve our water quality at www.discoverycwa.org.

Staying ahead of reliability and resiliency needs is vitally important. By proactively planning now, the Alliance ensures that ample wastewater treatment facilities can provide reliable service at an affordable rate well into our future.

Odor Control: Biotrickling FilterTwo new biotrickling filters will be constructed to reduce odors. Odorous air collected from the first two steps in the treatment process moves through a silo-like structure that contains a plastic media growing a layer of bacteria called a biofilm. Multiple types of bacteria live on the surface of the media where they break down various organic compounds which cause odors.

Increased Capacity: Biosolids Conditioning EquipmentA new processing system will be added that will help make the final biosolids product drier, which will reduce the number of truck trips required through the neighborhood by about 10 percent.

Increased Capacity: New BlowerA fourth blower, a machine that provides air to the aeration basin, will be added to this building.

Increased Capacity: Chlorination SystemA small amount of liquid bleach will be kept on site and used on an as-needed basis to discourage growth of certain bacteria that are harmful to the treatment process.

Demolished Structures

Visit us online at www.discoverycwa.org

FundingPlanning, design and construction costs for the project are covered in the Alliance’s Capital Plan, which includes funding for all long-range planning projects such as this one. The operations and maintenance costs associated with power and general maintenance for the odor control system will be factored into the annual operating costs for the plant. In total, the project is anticipated to cost approximately $24 million. Those costs are allocated to the two funding members of the Alliance partnership – the City of Battle Ground and the Clark Regional Wastewater District. The City and the District, in turn, make the final decisions on what rate and charge structures are appropriate for their customers in paying for the project. The City and District have included the project costs in long range financial planning efforts to ensure overall affordability of rates and charges for everyone.

Project Timeline There is a great deal that needs to be completed before construction can begin, including detailed design and engineering, acquisition of the necessary permits, and selecting a construction contractor through a competitive bid process.

2017 2018 2019 2020 2021 2022Current Phase: Planning and Preliminary Design

Permitting

Final Design, Bidding and Construction Early milestone for odor control system.

Stay Up to DateThroughout the project, interested community members can follow progress and provide feedback through the Alliance website, www.discoverycwa.org.

For More InformationContact Adrienne DeDona, Public Outreach Manager, at (360) 903-4792 or adrienne@ jla.us.com.

Reliable, expandable sewer service is essential to our economy and the health of our communities and environment.

Salmon Creek Treatment Plant Improvements Fact Sheet — Page 4