Zoos are turning the droppings of animals into compost
By MARC BENJAMIN
Fresno Chaffee Zoo’s waste is no longer going to waste. Zoo officials have embarked on a new project to cart dung from elephants and other vegetable-eating animals to a corner of the zoo’s service yard. The plan is to water, turn and age the scat for several weeks until it turns into compost and can be used for landscaping.
In addition to saving on hauling and composting costs, Chaffee Zoo in Fresno, California, might start marketing its end product later this year, officials said.
“With all the talk we do about the environment, we want to practice what we preach,” said Steve Feldman, spokesman for the Association of Zoos and Aquariums. “More and more zoos are starting to recognize and use this valuable resource.”
Tucson’s Reid Park Zoo donates some of its composted waste to a farm operated by a community food bank, where produce is grown and then sold at local farmers markets, said Jed Dodds, education co-ordinator for Tucson Zoo.
At the zoo in Columbia, South Carolina, manure entrepreneurs are selling “comPOOst;” in Seattle’s Woodland Park Zoo, it’s known as “Zoo Doo”.
John Davis, curator of mammals and manager pf the comPOOst operation in Columbia’s Riverbanks Zoo, said the soil additive is helping keep the landscaping lush. And purchasers also say good things.
“We have return customers who say they are pleased with how it’s working,” Davis said. “But, I can’t say it’s that much better than (other) compost.”
The money earned through sales pays for conservation programs that Riverbanks Zoo participates in around the world, Davis said.
Woodland Park Zoo sells its Zoo Doo to the public by the truckload or in containers. There are 28 different types of animals that contribute to the zoo’s programme, said Dan Corum, the zoo’s self-proclaimed curator of “endangered faeces.”
Corum said the zoo earns about US$15,000 (RM46,500) from Zoo Doo sales annually and also saves about US$60,000 (RM186,000) by not having to send millions of tones of waste to the landfill each year.
One of the nation’s longest-running composting projects is at the North Carolina Zoo in Asheboro. Over 13 years, the zoo has saved US$1.5mil (RM4.65mil) in landfill and landscaping costs, said Gin Wall, curator of horticulture.
“We use every bit we can get.” Wall said. “It has more than paid for itself.”
Chaffee Zoo employees on doo-doo duty are mixing elephant dung with leftover straw, landscape clippings and fruit and vegetables that can’t be used as feed. Eventually, they’ll also use dropping from the zoo’s zebras, giraffes and addax to create the compost material.
Only herbivore eliminations are used; the fecal material from carnivores can contain parasites, but samples also are being taken to ensure that parasites haven’t been left behind by herbivores, said Scott Barton, Fresno Chaffee Zoo director.
Fresno Chaffee Zoo’s two elephants produce about 55 tonnes of stool annually. All the zoo’s waste hauling is paid for by the city of Fresno. If all the zoo’s elephant dung is used in composting, the city would save about US$11,000 (RM34,100) in disposal costs, said Ann Kloose, city of Fresno public utilities spokeswoman.
To become a usable soil additive, the waste is built into windrows; zoo employees must turn, water and take its temperature for weeks, said Greg Gorby, the zoo’s horticulture manager.
Becky Thompson, a local gardener participating in the Fresno zoo’s project, said that for the poop to compost properly, the temperature must remain between 49° and 60°C.
“If it gets too hot, it will kill the bacteria, and if it gets too cold, the bacteria slows down,” she said.
If the pile rises to 71°C or more, it could spontaneously combust, which is why the zoo is acquiring a thermometer to measure internal temperature of its manure piles.
The key to the composting process is the activity of microbial bacteria, which need water, food and a steady diet of fecal material, Seattle’s Corum said.
The corner of the yard where the brown matter is stored at Chaffee isn’t stinky and has not attracted large number of flies.
Zoo poop from plant-eating animals typically is less odoriferous, Corum said.
“We are only working with herbivore manure, which smells notably less than, say the household cat box or the steamer the neighbor’s dog leaves on the parking strip,” he said. “Odour is not an issue with well-managed compost piles. Finished quality compost does smell, in a good way, like forest duff.”
The Fresno Bee/ McClatchy- Tribune Information
