Omaha zoo uses compost farm to manage animal waste
OMAHA, Neb. — Elephants poop 12 times a day.
Each massive pachyderm eats 100 pounds of hay every day. They spend 18 hours a day eating or pooping.
Somebody has to clean up that mess, 20-pound pitchfork scoops at a time.
Anyone who owns a dog knows that nature doesn’t reclaim your puppy’s poop as fast as your furry friend can produce it. Now imagine your dog is an elephant. Now six elephants. Now six elephants plus a herd of giraffes, a handful of rhinos and a smorgasbord of other critters that, no matter how long you pray, just won’t stop defecating.
That’s a heck of a load.
At the Henry Doorly Zoo & Aquarium, managing animal waste is a nonstop battle. It’s one that requires heavy lifting, long hours and a smart plan, one that took decades to evolve.
The zoo has stored its animal waste in a gigantic pile down a southern hillside for decades. It’s a pain to get to, but at least it’s out of the way.
Longtime zoo director Lee Simmons planned to build a concrete poo chute that would allow zookeepers to wheel containers full of waste to the edge of a ramp atop the hill, then spill the goods down onto the hillside. He even had six concrete footings poured — which are still in place today — but the project was never completed.
Until recently, the zoo simply piled all its animal dung on the hillside bordering the BNSF Railway and let it return to the earth naturally.
“The guys from the rail yard would call (a couple times) and say, ‘Hey, your (dung) pile is on fire,’” said Dan Cassidy, a longtime zoo employee and current vice president of animal management. “It’s not part of our proud past.”
The zoo experimented with on-site composting techniques, but Cassidy said none of the ideas worked out very well. Recently, the zoo built a concrete pad on the same hillside and hired a compost farm to haul away its animal waste every month, the Omaha World-Herald reported.
Instead of melding into the hillside, zoo poo now goes back into landscapes, garden beds and, in some cases, hay fields.
To illustrate the digestive life cycle of an elephant’s breakfast, let’s follow the hay.
Regional farms stock a drive-thru hay barn north of the Asian Highlands exhibit. A semitrailer backs up to the rear of the elephant barn so zookeepers can keep the hay supply running.
The zoo’s six elephants forage for 18 hours a day. They strip bark from branches and chomp on produce, but hay makes up the bulk of their diet. Each animal eats about 100 pounds of it every day, and elephants digest less than half of what they eat. That means that their waste is packed with hay and other food remnants. Elephants leave droppings 10-12 times a day, each at least twice the size of a large burrito. Zookeepers said elephants, rhinos and giraffes produce an overwhelming majority of the zoo’s animal waste, more than all the other species at the zoo combined.
Every morning at 8 a.m., zookeepers turn on music and start scooping. It takes about two hours, using shovels and pitchforks, to clear the main indoor living space of feces and hay. Then it’s another hour to clear additional pens. They return in the afternoon for another hour or two to clean again.
All the poo at the zoo winds up in an area called the “Baja.” On the hillside south of the elephant and lion habitats, a roughly 8,000-square-foot concrete pad stores piles of sticks, mulch and excrement.
A side-dumping truck from Ashland compost farm Soil Dynamics hauls the zoo’s compost away about once per month. A John Deere loader carves into the steaming mountain of animal waste and packs it in the dump truck. Each load weighs about 25 tons, and it takes many loads over about a week to clear the zoo’s stockpile. The dump truck delivers the load to a compost farm bordering the zoo’s safari park in Ashland. There, it is mixed with grass clippings, wood chips and food waste from local schools and processed into usable compost. The final product is delivered to local landscapers, nurseries and gardeners.
That compost that began with a few bites of hay now returns to the earth. Some of it may even be used to grow new hay. And the life cycle starts anew.