Correction appended

Theis headed for greener pastures with its plan for the first biodigester at a U.S. zoo.

The $1.1 million project will convert the 400-500 tons of manure and other organic waste produced annually at the zoo into methane-rich gas to power the 18,000-square-foot

The biodigester will also produce compost for the animal habitats, gardens and public spaces on the zoo's 125 acres, saving it $70,000-$80,000 in energy costs and another $30,000-$40,000 in waste disposal fees.

With construction scheduled to launch in June, the project could be completed by October.

The estimated cost for the project "is a pretty big barrier to entry for most zoos," COO Gerry VanAcker said. "But we expect a return on investment in close to 10 years."

The Detroit Zoo has set a goal to be zero-waste by 2020. And the biodigester "gets us a lot closer to that goal," he said, while generating 7 percent to 8 percent of the zoo's annual electricity needs.

The project has been in the works for the past couple of years.

Two renewable-energy grants totaling $27,000 from thefunded a two-part feasibility study conducted by's Anaerobic Digestion Research Education Center.

With the rest of the grant, the zoo hired, Detroit, to develop a blueprint for the facility, which will be northeast of the administration building.

Detroit-basedis contractor on the project.

Thegave a $600,000 grant, thanks to zoo trustee John Erb.

And the MEDC has committed up to $100,000 for the project through the Public Spaces & Community Places program, which provides matching grants for public space projects supported through online crowdfunding platform

The zoo plans to chip in $100,000 from its 2015 capital budget and has $100,000 grant proposals in to theand the

Although the biodigester is not a typical community place-type project, "we saw this as a great opportunity because it is a place that attracts a significant amount of the public and it brings such a huge, important aspect of sustainability and promoting green elements," said Lisa Pung, community assistance team manager at the MEDC.

The biodigester is expected to produce three-quarters of the electricity needed for the health complex, which functions like any hospital with X-rays, surgeries, medication dispensing and a nursery.

MSU's Anaerobic Digestion Research Education Center will help launch the biodigester and operate it for the first year under a $100,000 contract, VanAcker said.

Zoo employees will shadow the MSU team so they can take over the operation after the first year. Estimates are that the biodigester will take just eight to 10 hours of staff time each week to operate, VanAcker said.

The zoo doesn't expect byproducts from the biodigester to trouble neighbors.

"The only times the smell is exposed are when the doors are open," VanAcker said. And "with all the bells and whistles we have in the design, it's going to be nearly impossible to explode."

The remaining compost left after the waste has released the methane gas may be used in gardening, and the zoo plans to use the majority of it on its grounds, VanAcker said.

Currently, the zoo collects organic waste in a truck that's much like a trash hauler and transports it tofor composting.

"We won't have to do that anymore, so we save the expense of tipping fees and won't have to replace the truck," VanAcker said.

Thein Munich, Germany, operates a biodigester, and theis in the initial phases of developing one through a public-private effort Detroit benchmarked, VanAcker said. None are operating at U.S. zoos.

"Detroit is clearly leading the way with the biodigester," said Doug Piekarz, CEO of theand past vice chairman of the' green scientific advisory group.

"We had looked at (one) ... but weren't able to do it because of code issues. ... Our solid-waste authority is attempting to work through those issues."

Conservation is a focus area for all AZA-accredited zoos and aquariums, Piekarz said.

In the end, you would do this where the ROI is reasonable, he said. And "based on what I know about Detroit's situation, they've gone about this exactly right."

The zoo project is likely to serve as a role model for other U.S. zoos, Piekarz said.

"Now we have someone to point to to say, 'If they could do it, why can't we?' "

Sherri Welch: (313) 446-1694. Twitter: @SherriWelch

Correction: The original version of this story incorrectly implied that the Michigan Economic Development Corp. was contributing $100,000 to fund the biodigester project. It has been corrected to state that the Detroit Zoo plans to invest $100,000 from its own capital budget in the project.