Tuesday - September 8, 2015

Green design features reduce carbon footprint of Lake Oswego and Tigard’s new water facilities

VFDs for the pump motors at the new intake

Solar panel array on the electrical building at the new water treatment plant

Native species and grasses were planted at the Bonita Pump Station

Being green is not easy, but the Lake Oswego Tigard Water Partnership was determined to incorporate energy-efficient elements in the design and construction of its $254 million water supply system.

In 2008, the cities of Lake Oswego and Tigard joined together to form a partnership to replace, upgrade and expand Lake Oswego’s old and undersized water supply system infrastructure, to ensure a long term, reliable supply of high-quality drinking water for both communities.

Partnership facilities under construction, including a new river intake pump station (RIPS) on the Clackamas River in Gladstone, an upgrade at the water treatment plant (WTP) in West Linn, a new reservoir in Lake Oswego, a new pump station in Tigard, and more than ten miles of large diameter welded steel pipe through four communities were designed with green attributes in mind and a requirement for a minimum 75-year operating life.

River Intake Pump Station – Gladstone

The Partnership recently received an Energy Trust award for implementing energy saving features into the new RIPS. This included installation of variable frequency drives (VFDs) for the pump motors at the new pump station.

VFDs allow the pump station to minimize energy demands and work more efficiently to achieve the daily flow requirements. The VFDs enable the new pumps to operate at different speeds to match water system demands. In addition, VFDs reduce wear and tear on motors, thereby decreasing maintenance costs and prolonging equipment life.

With the installation of the new VFDs, this facility will reduce its energy consumption footprint by more than half a million kilowatt hours per year.

In addition, new fish screens at the intake, along with river channelization that was completed upstream of the new structure, make the new RIPS much more “fish friendly” than the previous intake. Extensive native species and shrubs were also planted in nearby Cross Park, and will be planted at the RIPS this fall. 

Water Treatment Plant – West Linn

Green design features and sustainable construction methods abound at the new water treatment plant:

  • A Large solar panel array installed on the new electrical building has 110 panels and a 30 kilowatt capacity. Power produced by the array is distributed to the treatment plant grid. Unused power is distributed back into PGE’s grid.
  • Energy efficient LED lighting installed in all new structures.
  • VFDs on three pump motors and reduced voltage soft starters on two motors, reduces the energy consumption footprint at the plant by more than one and a half million kilowatt hours per year.
  • Garden roofs on the finished water pump station, electrical building and administration building reduce storm water runoff and roof temperatures, thereby reducing heating and cooling needs.
  • Screw presses instead of commonly used centrifuges to de-water plant solids saves an additional 32,000 kilowatt hours per year.
  • A water source heat pump uses water produced in the plant to provide building heating and cooling saving additional energy over conventional roof-top heat pumps.
  • During demolition of the existing buildings, all concrete is crushed and reused on site, steel is sent to an offsite recycler, and wood is sent to a chipping facility for reuse.
  • The washwater recovery basin recycles water used during the filtration process.
  • The sand pumps recycle sand in the ballasted flocculation process.
  • Pervious materials used for driveways and sidewalks reduces runoff and, on-site swales and ponds allow rain to infiltrate and replenish groundwater.

Waluga Reservoir 2 – Lake Oswego

  • The site underwent extensive invasive species removal, which was replaced by native trees, shrubs and flowering plants. Native plant materials require less water and maintenance, while providing habitat and food sources for local wildlife.
  • Excavated rock was crushed and reused on site.

Bonita Pump Station - Tigard

  • Invasive species were removed onsite and a vegetated corridor was created around the pump station, which acts as a buffer zone to protect the surrounding wetland area. Native erosion control grass and a variety of native plants, selected from the Clean Water Services approved list, were installed at the site to help enhance the wetland area.
  • Skylights help reduce the need for conventional lighting
  • All pump motors utilize VFDs and reduced voltage soft starters.

More than ten miles of large diameter, welded steel pipeline – Gladstone, West Linn, Lake Oswego, Tigard

  • Hydraulic analysis methods were used to optimize design for maximum flow efficiency and reduced pumping costs.
  • High performance coatings and linings were used to minimize friction losses in pipelines and protect against corrosion.
  • Double lap welds on every joint provides a high degree of protection against seismic forces.
  • Cathodic protection systems supplement high performance pipe coatings for increased corrosion protection and longevity.

Designing green takes more effort, however, these techniques allow the Lake Oswego Tigard Water Partnership to plan for current and future water needs in a responsible, environmentally-friendly manner.