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Construction methods and sustainability

Learn how King County Wastewater Treatment Division uses safe and sustainable construction methods.

Construction methods 

Learn how King County uses different construction methods to create safe underground working conditions with minimal impacts to nearby neighbors. 

Video 1. Secant piles (2:52)

King County Wastewater Treatment Division uses long cylinders of concrete called secant piles to keep construction workers safe and protect, homes, streets and utilities. Watch the video to learn more!

Video 2. Soil mix wall (3:12)

The King County Wastewater Treatment Division uses soil mix walls to create safe work areas and minimize construction vibration and noise for nearby neighbors. Watch this video to see how the method works.

Video 3. Sheetpile driving (3:07)

King County Wastewater Treatment Division may use sheet pile driving to create safe underground work conditions. Watch this video to understand how using a vibratory hammer to install sheet piles works well in small spaces.


Video 4. Microtunneling (2:16)

When the King County Wastewater Treatment Division projects need to go under roads or water bodies, microtunneling is often the right way to build. Check out the video on how we do it.


Video 5. Horizontal directional drilling (2:16)

Learn how King County Wastewater Treatment Division uses Horizontal Directional Drilling (HDD) to reduce surface impacts of underground pipe installation. HDD allows construction crews to install a pipe without digging a trench. This is especially useful when the surface contains homes, buildings, and environmentally sensitive areas.

Video 6. Open cut (3:33)

King County uses “Open cut” construction to install pipes that run close to the surface. This video shows how open cut construction affects drivers, bikers and neighbors, and what King County does to minimize impacts from the work.

Video 7. Street work construction techniques (2:38)

King County Wastewater Treatment Division projects often includes work in streets. This video shows how street work construction affects drivers, bikers and neighbors, and what King County does to minimize impacts from the work.


Video 8. Sewer Pipe Lining (4:04)

Learn how King County repairs and protects pipes from degradation using a technique called “lining.” See the above- and below-ground processes used to apply an adhesive liner to the sewer pipe’s interior and to keep crews working inside the safe.

Sustainable construction 

Learn how King County diverts construction waste from landfill through recycling and salvage, and designs facilities to be "green" and energy efficient. 

Video 9. Georgetown Wet Weather Treatment Station - making construction sustainable (3:56)

This treatment station will collect and clean up to 70 million gallons per day of wastewater and stormwater that would have spilled into the Duwamish River in heavy rains. King County wanted construction to be just as sustainable as the new facility will be. See how the Georgetown project team and our contractor worked together to make the demolition phase fit that goal.

Video 10. Energy-efficiency reaps rewards for sewer utility ratepayers (2:27)

The wastewater treatment process is energy intensive, and WTD is the largest user of electricity in all of King County government. King County will protect regional water quality while reducing energy consumption at the South Treatment Plant in Renton thanks in part to a generous grant from Puget Sound Energy. The PSE grant will help cover the cost to install new two energy-efficient agitation air blowers that pump air into wastewater so beneficial bacteria can more efficiently break down and treat pollutants.

Video 11. Barton roadside rain gardens (2:37)

See how King County used green infrastructure to build a CSO control facility in West Seattle. King County's Barton CSO Control project constructed 91 roadside rain gardens on 15 blocks in West Seattle. The project, completed in 2015, is a type of green stormwater infrastructure

Video 12. Roadside rain gardens and their neighbors (2:30)

Visit King County’s Barton CSO project’s roadside rain gardens, and hear from project neighbors.

Video 13. Barton roadside rain gardens -- before and after (0:55)

How do roadside rain gardens transform a neighborhood? This video slideshow offers a "before" and "after" glimpse of our Barton CSO Control Project in West Seattle.

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