Zoo cuts carbon footprint with Ecodrum system

Natural waste is a fact of life, whether you live on land or in water, walk on two legs or four. It might not make the best topic for dinner conversation, but with the addition of two elephants in the future, the Birmingham Zoo is making plans to deal with the addition of the waste of two more elephants with an Ecodrum.

“It’s a contained, natural compost system,” said Stephanie Slade, the zoo’s vice president of living collections, describing the new machine.

While the Ecodrum will be a large addition — its capacity is 10 tons — Slade said the zoo and former president William Foster planned long ago to integrate something similar for the elephants and other hay grazers. A spot near the elephant habitat is already designated and built specifically for the Ecodrum, and it was built so it is already at a functional level for zookeepers. 

Slade also said because it is enclosed, it hides any smells guests may have been encountering during their visit.

“While for me that’s part of the zoo experience, that’s probably a lot of people’s least favorite parts of the zoo experience, the smell of it,” she said.

The elephants alone eat more than 200 pounds of hay per day, and combined with the zoo’s other hay consumers, they can produce seven to eight tons of byproduct each week. This waste will now go in the Ecodrum to produce a usable byproduct.

Slade said the drum is built on a mechanical corkscrew system to turn the waste, and the drum will contain the natural heat that is created through composting. This gives the byproducts everything needed to make it functional.

“At the end of all this turning, at the end of about two weeks, out comes this usable product,” Slade said. That usable product is mulch. “We use a ton of mulch around zoo grounds,” she said. Although it takes two weeks from start to finish for the byproduct to be transitioned into mulch, the setup of the Ecodrum is such that staff can continually add waste without stopping the process.

Slade said the composted mulch won’t be placed in areas that people come in direct contact with, such as playgrounds, but it will be used in areas like flowerbeds and along walkways. She explained that using the composted mulch is not only better for the zoo — it is organic, local fertilizer and nearly eliminates the need to purchase mulch — but it is also fits withinits mission for ongoing conservation.

Instead of using Waste Management to ship the byproduct off-site, as the zoo currently does, this composter will allow staff to cut out a large portion of their carbon footprint by composting it in-house. It greatly reduces chemicals used in standard mulch that would flow into local waterbeds after rains and lessens the number of mulch bags that get thrown away. And, there is less waste going into the landfill.

“You kind of get to hit on every little step along the way,” Slade said. 

Slade said composting used to be less attainable but now it has gained traction, and it is easier for companies and organizations to take part. Eventually the zoo plans to incorporate education about the Ecodrum and its process throughout the zoo so visitors can learn more about composting and its benefits. The education will also show which animals are contributing. 

“It’s continuing to allow us to live our mission, to live our AZA accreditation and to walk our talk,” Slade said. “I think that’s what I like the best about it.”