PENE MITCHELL AND PAUL HARREY started small … with a bucket of worms … but their passion for sustainability has led them to the creation of OSCA – an on-site, commercial , waste-to-compost technology, designed to convert tonnes of organic waste into nutrient rich compost.
THIS PAIR of techno doctorates believes they have designed a machine that will solve the problem of large scale food waste from restaurants, schools and resorts, producing useful garden compost and taking pressure off our landfill sites.
A state government grant gave Pene and Paul the chance to build the first two of their composting units on their new property at Palmwoods. They’ve come a long way from their Worms Downunder worm farms that convert school and cafeteria food waste to a liquid soil conditioner.
Paul is an industrial designer and has a doctorate in electronics manufacturing. Pene is an architect and she has a doctorate in sustainable architecture. Their common interest is sustainability. In fact, that is how they met … at a sustainability conference in Tokyo.
“We realised that worm farms are OK,” says Paul, “but they struggle on a larger scale, and they need someone to look after them. So we realised we needed a composting system that could be run by a computer.”
OSCA looks very basic, and it is. Inside its tube-like structure, organic waste is broken down quickly and naturally, using an aerobic process. This involves the use of an auger to aerate, agitate and move the waste through the machine.
Through the action of the beneficial bacteria in the machine, the waste is effectively pasteurised as temperatures reach in excess of 60 degrees Celsius.
It’s silent, odourless and, remarkably, the whole system runs on the same energy as it takes to run a light bulb.
It can obviously cope with soft foods, but what about challenges like coconuts and animal bones? Paul calls this a contamination issue.
“We have worked very hard to ensure OSCA doesn’t break down. We have had knives and forks and bowls go through and they just get rumbled around. Where there is something that can physically stop the paddles, we’ve designed the machine so that it senses there is something wrong and sends an alarm signal. So it is very safe.”
It looks simple and Paul says it isn’t new technology. “There are other companies around the world doing this, but ours is slightly different. We have three Australian innovation patents on it.”
“For me it’s about keeping it simple,” adds Paul. “Making it engineered so that the parts don’t wear out. It’s fully stainless steel and there is a very heavy duty gear box which we think will last forever, because it’s only running once every half hour. It provides a huge amount of torque.
“If you typically mulch a food waste you effectively reduce its volume by 50 per cent. If you then take out some of that moisture as well, you further reduce the weight. Food waste is something like 75 per cent water. So really, all we are currently doing is taking dirty water to landfill.
“We are very keen to take food waste out of the landfill equation because food waste decomposes very quickly. Food company bins have to be emptied on a regular basis to avoid smells and other health issues. So, there’s a real cost issue in getting rid of food waste.
It is early days but Paul and Pene are talking to RSLs, local food caterers, large pubs, zoos, and local shopping centres about installing OSCA units. They are also keen to keep this technology local, with all components made on the Coast or in Brisbane.
The couple have been approached by consortiums of like-minded restaurants for example, where one of the restaurants could house the OSCA machine which the others all use to process their food waste.
Needless to say, there’s more to marketing OSCA than feeling good about making compost. The cost is crucial.
“We spoke to a local RSL that was paying $50,000 a year for their total waste disposal,” explains Paul. “So we worked out that one of our small machines, which can process up to a tonne of waste a week (and is on the market for about $35,000), could handle all the food waste disposal and save them $25,000 a year.”
“The whole theory is to put a unit on-site and leave it there,” adds Pene. “So people can see that they are closing the waste cycle. They can put organic waste in, and then use the resulting compost on their gardens – restaurants can use the compost to grow their food. It closes that loop.”
In terms of marketing their new industrial product they are happy to sell the units either outright, to lease them, or rent them out. “
Maintenance is minimal,” says Paul. “It’s been designed so really the servicing will be mainly safety checks. The gear box doesn’t require any servicing. Bearings will need to be re-greased, but apart from that it is a very robust system.”
For Paul and Pene OSCA is not only a test of their design and development capability but it’s a test of their belief in sustainability. They see each OSCA owner as sending a very clear message that what’s important to their company is taking responsibility for their own waste.
And the generated compost can be used on-site given away to staff or even their suppliers and customers.
“It’s not acceptable to put this stuff in the ground any longer,” says Paul warming to his subject. “We are in serious trouble in terms of climate change, and that message can be passed on to their staff and their customers.”
“We’re land filling something like 14million tonnes a year of organics in Australia. On the Sunshine Coast one of our largest contributions to greenhouse gases is our landfill sites.”
Long term Paul would like to see OSCA exported, as he wants to see a world-wide reduction in organic waste-to- landfill practices, and an increase in organic matter returning to the soil where its benefits include carbon and water storage.
“Our passion is sustainability,” says Pene with a determined smile. “Once we have got this waste issue resolved we will move on, maybe into electronics waste. Our passion is just to make a change.”
For further information about OSCA, phone: 07 54459704 or email [email protected]