"This is an excellent opportunity for us to educate the children and keep the environment healthy," said executive director Gregory Dunn.

The Makiki facility will have natural ventilation and lighting to minimize the need for electric-powered cooling and lighting. Where possible, building materials will be recycled. Where that's not possible, the best alternative will be selected, Dunn said. For example, all building lumber will be from forests that are certified as being sustainably managed.

The facility will capture water off its roofs, which will be used for irrigation and to flush toilets.

In the design, "we will try to bring the out-of-doors indoors," said nature center O'ahu operations director Ramsay Taum.

Creating a Food web

Another key feature is a hydroponic sewage treatment facility called the Green Machine, which runs visitor center effluent through a series of tanks filled with fish, snails and native Hawaiian plants whose roots hang down in the liquid. By the time the effluent gets to the end of the system, it's clear and clean enough to be used for irrigation.

The Green Machine is operated by Partners in Development. The firm's Chad Durkin said the system has 14 stainless steel tanks capable of operating as two separate 7-tank lines.

"We give the water enough time that by the time it reaches tank 4 or 5, it already meets Health Department R2 standards for irrigation," he said.

"It is basically a food web. As the water moves through the tanks, the quality is changing biologically as well as chemically," he said. There is no odor associated with the facility, he said.

The Green Machine is itself a recycled facility, which was designed by Ocean Arks International and started life as a demonstration plant in San Francisco. It later was used to treat piggery effluent at 'Ewa Beach, and has now been refurbished and installed at Makiki, said Durkin.

A walkway lets visitors view the process from above, so it can be used to teach students and others about the use of natural systems to treat wastewater.

"The system is really oversized for the application, but we're there for education," Durkin said.

Looking for money

Dunn said the Hawai'i Nature Center has run up against higher shipping and construction costs that have driven a $2.2 million budget to near $3 million. The organization is trying to raise money to make up the difference, but may need to find ways to cut costs.

"We're trying to build the structures to LEED certification," he said, referring to conservation-oriented Leadership in Energy and Environmental Design standards. But in some cases, meeting the standards—while it may save money in energy costs or building life in the long run—can be more expensive up front, and the center may need to make sacrifices in some cases to meet budgets, he said.

He said the center is specifically looking for money that will pay for a solar photovoltaic array that will allow the facility to produce its own electricity from sunlight.