Blackwater is LEED golden for Port of Portland building

Oct. 1, 2009
Green plumbing and mechanical contractors can add another weapon to their water conservation arsenal — blackwater recycling.

PORTLAND, ORE. — Green plumbing and mechanical contractors can add another weapon to their water conservation arsenal — blackwater recycling. A product created by Worrell Water Technologies, Charlottesville, Va., is being installed in the Port of Portland's new headquarters office building at Portland International Airport that will recycle blackwater from the toilets and send it right back to flush the toilets.

The product in the Port of Portland office building is called the Tidal Wetlands Living Machine; its end product is tertiary treated water.

The 205,000-sq.ft. building will also incorporate a 10,000-sq.ft. green roof, a ground-source heating and cooling system, active/passive radiant ceiling panels, daylighting for the office and garage, and water efficient fixtures. The port authority is shooting for a Leadership in Energy and Environmental Design Gold certification for the $241 million structure, which is scheduled for completion next spring.

The Living Machine system will be an architectural centerpiece in the lobby of the new office building, which is adjacent to the airport terminal building.

The Living Machine system is a proprietary, on-site ecological wastewater treatment approach that produces recycled water out of both gray and blackwater without chemicals, odor, by-products or high energy usage.

The current version of Worrell Water Technologies was formed about three years ago from a group of companies owned by Tom Worrell, William Kirksey, senior vice president, Worrell Water Technologies, told CONTRACTOR. The first patent on the Living Machine was issued about a half dozen years ago. The company has around 20 employees, most of which are scientists and engineers.

The biggest difference between the Tidal Wetland system and conventional water treatment, Kirksey explained, is that conventional systems are once-through processes. The Tidal Wetland system cycles the water through treatment cells 10-12 times a day.

“We cycle water like a tidal wetland,” Kirksey said. “It contains a packed bed of treatment media, which is common for water treatment systems in that there is a lot of surface area for biofilms to grow. But where we differ is that we cycle the water through in a way to allow bacteria to get a lot of oxygen without having to force oxygen into the water, which uses a lot of energy.”

The rapid cycling brings in oxygen at high levels with low energy cost and also shrinks the footprint. Kirksey noted that a typical rule of thumb is 150-sq.ft. for every 1,000 gal., so, for example, if you have a 10,000-GPD system, you would need 1,500-sq.ft.

Kirksey said that what looks like lobby planter boxes is the majority of the system. Any kind of on-site wastewater treatment plant is going to have a primary tank to catch indigestible solids and plastics. The one in the Port of Portland project is just outside the building underground; that's the main subsurface item other than connecting piping.

The effluent moves from the primary tank into it the first wetland cell.

“We have a dosing set up so that incoming polluted water or sewage water is mixed with treated water from the back end of the system in order to equalize loading across the system rather than overloading the first cell and having light treatment on the last cell,” Kirksey explained.

Worrell Water assembles its own tanks made from a plastic tank that's typically used for sewage treatment. The firm customizes the tanks with pumps, float switches, and other controls. They tend to use a lot of Grundfos pumps. They have their control panels built for them.

“Typically we have six cells, although we have done some installations with four,” Kirksey told CONTRACTOR. “We usually have four main cells and two polishing cells at the end. The water at the end is tertiary treated water. The levels for Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and total nitrogen are 10 mg/l. Those parameters are the typical permit limit. Our most recent systems have been producing treated water at less than 5 mg/l concentrations.”

Because most employees of Worrell Water would be more at home wearing lab coats than with tool belts, they depend on mechanical contractors to get the systems installed. Worrell might have three contracts on a project, Kirksey explained: a design-assist contract with the architect, an installation oversight contract with the general contractor and an O&M contract with the owner, although they would subcontract that out to a contractor.

As part of its ongoing focus on sustainable practices, the Port decided to build its new offices atop a new seven-story parking garage that was already in Port expansion plans, and design the new three-story office building as a showcase for sustainable practices.

“The Port of Portland is committed to incorporating sustainable practices in all of our operations,” said Stan Watters, director of development services and information technology at the Port. “The Living Machine is truly a centerpiece for the comprehensive green building strategy we have initiated for this entire project. The Living Machine system is also an important part of our effort to obtain LEED Gold certification for this building.”

The Port of Portland had multiple objectives for the wastewater system in its new headquarters. It had to be sustainable, cost-effective, attractive, and allow reuse, but above all, it had to provide advanced wastewater treatment. The system will treat up to 5,000-gal. of wastewater a day and then use UV light to ensure no bacterial contamination before it is pumped back up to the office to a quality suitable for re-use in toilet flushing.

The Living Machine system at the Port of Portland is designed to fit within a 700-sq.ft. area in the lobby.

“Port office visitors and employees will only see lush vegetation in packed gravel, unaware that underneath are holding tanks, or cells, that are alternately flooding and draining to create multiple tidal cycles each day for water treatment and recycling,” said Kirksey.

Architectural firm Zimmer Gunsul Frasca is working with Worrell Water Technologies to ensure the Living Machine system is aesthetically appealing.

“The Living Machine system is the single most impressive green strategy of the building,” said Doug Sams, project architect and associate partner at ZGF Architects LLP. “It hasn't been done on a building of this size in Oregon. It supports the Port's larger environmental goals and showcases to others how sustainable principles can be applied in large commercial settings.”

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About the Author

Robert P. Mader

Bob Mader is the Editorial Director for Penton's mechanical systems brands, including CONTRACTOR magazine, Contracting Business and HPAC Engineering, all of which are part of Penton’s Energy and Buildings Group. He has been  with CONTRACTOR since 1984 and with Penton since 2001. His passions are helping contractors improve their businesses, saving energy and the issue of safeguarding our drinking water. He is a graduate of the University of Notre Dame with an A.B. in American Studies with a Communications Concentration.

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