King County’s Wastewater Treatment Division will do its part to support regional environmental priorities in 2016 by investing more than $196.8 million in dozens of vital sewer improvement projects.

Projects entail upgrading aging facilities so they continue to operate reliably and adding new capacity to serve the region’s rapidly growing population.

Other priorities include investments in projects that will support the cleanup of Puget Sound and the Lower Duwamish Waterway, and controlling overflows of stormwater mixed with sewage during heavy rains.

King County operates a regional wastewater treatment system that includes 391 miles of sewer lines, 47 wastewater pump stations, 19 regulator stations, four stormwater treatment facilities, three regional wastewater treatment plants, and two local treatment plants in Vashon and Carnation. The system serves 1.6 million people across a 424-square-mile area in the central Puget Sound region including parts of Snohomish and Pierce counties.

The announced projects come on the heels of news that solid credit ratings and favorable financial market conditions continue to benefit ratepayers served by King County’s Wastewater Treatment Division for sewer improvement projects that safeguard the environment and support continued economic growth.

On Monday, the King County Council approved a bond refinancing of $281.5 that will yield about $65 million in savings over the next 25 years.

Here is a highlighted list of projects scheduled for 2016 throughout King County’s regional wastewater service area:

East King County

Lake Hills/NW Lake Sammamish Interceptor Upgrade: King County will budget $4 million in 2016 to begin design on a project to upgrade 21,000 feet of aging pipeline in Redmond that has been in service for as long as 60 years. The new pipeline will increase system reliability and accommodate population growth.

North Creek Interceptor Project: The County will invest $22.8 million to complete construction to repair and replace a 2-mile pipeline that has been serving the Bothell area since 1970. The new pipeline will increase system reliability and accommodate population growth in this portion of the service area.

Sunset/Heathfield Pump Stations and Force Main Upgrade Project: In 2016, King County plans to invest $4.7 million to upgrade two pump stations in Bellevue as well as connecting sewer pipelines. The project also entails upgrading the Eastgate Trunk structure near I-90, which enables wastewater from these pump stations to get to King County’s South Treatment Plant in Renton.

North Mercer Island and Enatai Interceptors Upgrade: In 2016, King County will budget $1.7 million to continue project planning and design to replace sewer pipelines that have served neighborhoods in North Mercer Island, southwest Bellevue and the town of Beaux Arts Village since 1970. The new pipeline is being designed to serve these communities for the next 60 years.

South King County

South Treatment Plant Improvements: King County plans to invest $12.7 million to replace or upgrade critical treatment plant equipment including pumps motors, and drives, which will improve system reliability, reduce maintenance costs and increase energy efficiency.

Kent-Auburn Conveyance System improvements Project (Phase B): This year, King County will invest $3.1 million to expand the capacity of the wastewater conveyance system in the south portion of its service area. Construction will include installing new sewer lines and replacing aging pipes in Pacific, Algona and Auburn. Work will also include modifications to piping at the Pacific Pump Station in Pacific.

Regionwide

Lower Duwamish Waterway Superfund: King County will budget $4.8 million to work on Superfund activities to address historically contaminated sediments in the waterway. King County will also maintain its involvement in the Lower Duwamish Waterway Group in 2016, which is currently working with EPA and the state Department of Ecology to identify a Superfund cleanup strategy.

Conveyance System H2S Corrosion Rehabilitation: King County will invest $3.9 million to repair and replace sewer pipelines throughout its service area that are deteriorating or damaged as a result of corrosion caused by hydrogen sulfide gas, which commonly occurs in sewage.

WTD Resiliency and Recovery Program: King County plans to invest $2.7 million to assess and retrofit sewer infrastructure and buildings in preparation for potential seismic events. The program goal is to protect public safety by avoiding or minimizing critical system damage that could occur during a natural disaster.

Seattle

Fremont Siphon Replacement Project: King County is budgeting $12 million to begin construction on a new pipeline beneath the Lake Washington Ship canal to carry untreated wastewater from Seattle’s Fremont neighborhood to the West Point Treatment Plant in Magnolia. The current pipeline has been in service for more than 100 years.

Georgetown Wet Weather Treatment Station: King County will invest $13.4 million to continue design on a new facility in Seattle’s Georgetown neighborhood that will treat up to 70 million gallons of stormwater and sewage that currently flows directly into the Duwamish River during heavy rains.

Rainier Valley Wet Weather Storage Project: In 2016, King County is budgeting $9.7 million to begin construction a new underground tank and sewer pipelines in Seattle’s North Beacon Hill and Columbia City neighborhoods, which will control overflows of stormwater and sewage into the Duwamish River during heavy rains.

West Point Treatment Plant Improvements: King County plans to invest $12 million on a number of improvements at its largest treatment plant. Projects include  upgrading and replacing aging equipment to ensure reliable operation and continued compliance with permit conditions.

Murray Combined Sewer Overflow Control Project: In 2016, King County will invest $12.5 million to complete construction on an underground storage tank at its Murray Pump Station in West Seattle. The tank is designed to contain up to 1-million gallons of stormwater and wastewater during heavy rains, which will protect public health and the environment by controlling combined sewer overflows that occur near Lowman Beach Park.