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The humble worm turns everything it eats into nutrient-rich fertiliser—even industrial waste. One scientist is bringing worms to big business, reducing rubbish and saving our soil in the process
In terms of worms, Dr Michael Quintern is thinking big.
Bigger than the kindergarten kids with their grubby jars of burrowing worms.
Bigger than the thousands of worms diligently chomping through bucket loads of kitchen scraps in domestic worm farms around the country.
Quintern is proposing large-scale worm projects as a key weapon against industrial waste and soil degradation.
The soil scientist — and long-term worm advocate — holds forth on his favourite topic with almost palpable enthusiasm.
The plan, he says, is straightforward: take the waste from large-scale industry that would normally end up in greenhouse gas-emitting landfills, and put it back into the soil as a valuable resource and soil conditioner.
“We have huge amounts of organic waste going to landfills. At the same time, soils have degraded rapidly in organic-matter content over the past few decades, due to intensive land management. Composting is done quite a lot to very high standards but much of the waste can be dealt with better by vermicomposting.”
His motto? National worming to combat global warming.
Worms have been recycling organic nutrients for over 120 million years. “It may be doubted,” Charles Darwin wrote in 1881, “whether there are many other animals which have played so important a part in the history of the world.”
More than 2,000 years earlier Aristotle described worms as the “intestines of the soil”, and a more accurate description of these super-efficient digesting tubes is hard to find.
Quintern’s job with Scion (the Crown Research Insititue formally known as Forestry Research) is to explore the vermicomposting of different waste streams to both reduce waste and provide an organic fertiliser to meet the needs of specific regions and types of land use.
Around the country, private agricultural enterprises are beginning to incorporate worm farms into their waste management programmes.
“From restaurants and hotels to supermarkets, hospitals and prisons, the opportunities for converting waste material into valuable fertiliser seem endless”
Since 2003 Ashburton Meat Processors has bypassed landfills to place its weekly load of paunch (the contents of an animal’s stomach) and pig hair in an on-site worm farm. Mixed with animal manure, carbon-rich paper and cardboard, the waste is transformed into a rich vermicast that can then be sold.
“It’s so obvious — you think why didn’t I do it before? It’s what nature’s been doing for centuries,” says Mary-Anne Mills from Verkerks, owners of the Ashburton abattoir. “And vermicompost is a natural deodorizer, so it has a good forest-after-rain sort of smell.”
From restaurants and hotels to supermarkets, hospitals and prisons, the opportunities for converting waste material into valuable fertiliser seem endless.
Scion researchers are now looking to worms as an environmentally friendly way of processing the estimated 400,000 tonnes of waste from the pulp and paper mills that end up in landfills each year. Trials combining the waste with the pestilent weed hornwort have been promising.
Worms are also being enlisted in the processing of dairy by-products in a bid to offset the carbon footprint that beleaguers that industry, while also reducing nitrate run-off, replenishing farmland and restoring water quality. Recent trials by Central Wormworx in Cromwell show that vermicast derived from dairy shed waste can be returned to pastures as a form of high quality top-dressing.
“It’s about getting soil living again,” says Greg Walker, director of Wormtech, whose vermicast soil conditioners are winning high praise in the kiwifruit and grape industries.
“People are starting to understand that modern farming procedures aren’t sustainable and that we need to start looking at the basics – at soil structure and at getting living organisms re-established in the soil.”
Even biosolids (the solid matter from sewage treatment plants) can be converted into a safe soil additive. Councils are struggling to find a sustainable way of dealing with this sludge, yet Wormworx has already shown that a mixture of biosolids and fruit pulp can be an effective soil conditioner.
“Drying biosolids for combustion takes a lot of energy and the ashes end up in landfills,” says Quintern. “That’s a great loss of nutrients. Worms will eat the bacteria from the sludge and turn it into vermicast. You couldn’t feed just sludge to worms – it’s very rich, like trying to live off chocolate – but you can combine it with carbon from cardboard or sawdust.”
Quintern concedes there is resistance to introducing biosolids into the food chain but, he argues, there are many life cycles between the original waste and the end product: sludge is converted into vermicast, then into pasture soil, then into grass, then into milk. Compare that to discharging sewage into the ocean, then eating fish from that ocean. That, he says, is a very short cycle.
In combination with other available by-products, processed biosolids could well be used to meet specific regional requirements.
Take the soil in Rotorua. (Rotorua, says Quintern, will be the international capital of worm farming by 2013.)
People used to add a trace of copper to compensate for the natural shortfall in the soil. Yet, thanks to the widespread use of copper pipes and water cylinders, local sludge already contains copper.
“Farmers could use the copper-containing sludge and apply it to their soils. This is what we should be doing. We need skilled councillors to oversee these issues, to understand the needs of different soils and different waste-producing industries.”
Vermicast not suitable for agriculture can be used as a valuable resource for landscaping, reforestation, biofuels (fast-growing forests like willow have a huge demand for organic matter and nutrients) and restoring soil fertility in areas depleted by invasive procedures such as mining.
Quintern is now looking at requests from Pacific and South Asian countries for new ways to treat organic waste.
“We’re looking at producing the highest quality vermicast, then finding the most suitable area to apply it,” Quintern enthuses.
“If we don’t treat our soils well the next generation will be in real trouble, but this way we can raise soil fertility. It’s a win-win situation. And we’re just at the beginning.”