Promoting themselves internationally is important for the Adelaide Convention Centre’s business, but many of the staff’s ambassadorial efforts are being outshone by a bunch of worms.

The Adelaide Convention Centre has won a series of local and international awards for sustainability practices. Strangely then, when CEO Alec Gilbert travels overseas people just want to talk to him about worms. 

The Centre’s worm farm is like almost any other, but bigger and located just off a little city backroad. Covering a 6m² area and containing about 450,000 worms depending on the time of year, the farm has chewed through more than an estimated 24 tonnes of food scraps since it was installed in 2008. 

The worms are only a small part of a broader sustainability program run by Alec and his staff, but other measures such as chemical-free cleaning and use of wind energy for power just don’t seem to have the same traction.

Alec Gilbert checks in on the worm farm

“The word of mouth is remarkable, you go around the world for work and different people will stop you and say ‘oh, you’re the guys with the worm farm’,” says Alec. 

The big silver dome that houses the worms has recently been forced to move as construction work at the Centre took over their former home near the riverbank. Now tucked in an incongruous corner off a deliveries road, the farm is waiting to be installed in its final location underneath the building where it will be artificially temperature controlled as necessary. 

Over the past six years, use of the worm farm to dispose of food waste associated with kitchen preparation – in combination with a biobin for things the worms won’t eat and donations to OzHarvest and Foodbank SA – has almost entirely stopped the flow of food waste from the Convention Centre to landfill. 

Some of the surplus vegetables from this stock are destined to become worm food

This obvious environmental benefit is not all the worm farm has achieved though, with Alec relating some unexpected side-effects. 

“Quite often when we’re recruiting staff they actually say that they like the culture of our organisation and they like the things we’re trying to achieve. Certainly people mention that in their interviews,” he says.

Event planning manager, Philip Wells, is also in charge of overseeing the Centre’s ongoing sustainability program and he says the worm farm has sacted as a community outreach measure. Having recently taken a tour of a Year 6 class to visit it, and then a branch of the Country Women’s Association to see it in the same week, he knows best the kind of reaction it engenders. 

“That’s quite deliberate as well,” says Philip. “We’re a Government-owned facility so we’re more than happy to share the news. It’s the public’s venue so it’s really good we’re seen to be responsible and approachable.”

The output from the hundreds of thousands of worms who chew their way through the chefs’ discarded vegetable peels and stubby carrot ends is a mix of dry “castings” and a liquid waste that can be used as a potent fertiliser. 

The castings are largely added back into the worm farm along with things like grass clippings, shredded paper and egg cartons to keep the environment healthy, but the liquid fertiliser finds its way into a variety of homes and garden beds. 

“Actually at one stage we had one of our client evenings and we had a little gimmick where we had these little package sample bottles of worm poo and worm pee that each person got,” says Alec. “But also the staff often take it, we used to use it around the gardens but of course that’s all been dug up at the moment, and Council accept it.”

“Some of the Community Gardens around the place use the by-product,” adds Philip.

With a lifespan of between 10 and 15 days and an impact across areas as diverse as sustainability, marketing and community outreach, it’s entirely possible that the worms are some of the most productive employees at the Adelaide Convention Centre.