A $900,000 trial project using insects to process waste is being developed in Thames, and organisers think it may hold solutions for dealing with commercial food waste, agricultural food waste, and even sewage solids.
The NOW Project – Natural Organic Waste Solutions – is being run in conjunction with the Seagull Centre. The three-and-a-half year trial will begin in mid-April.
The project will initially use food waste from Thames Hospital, Richmond Villas, and Bupa Tararu Retirement Village, along with a number of schools and commercial businesses including a mussel farm and a Coromandel brewery.
Collected food scraps will be run through a grinder and placed on trays impregnated with black soldier fly larvae, which are being bred specifically for the project.
The larvae will process the waste during their 10-day growing cycle, and will then be sold as feed for animals, such as fish and chickens. Their manure, known as frass, will be used as fertiliser.
The waste processing facility will be located at the Seagull Centre, in three shipping containers which can each hold up to 500 trays. The containers will be fitted out with ventilation and biofilters, and all food waste and insects will be securely contained.
Trial organiser Louise Deane from the Seagull Centre said larvae were very efficient at processing waste.
“The larvae can eat an enormous amount of food [and] can grow enormously fast,” she said.
“Worms will take six months to process waste – This sort of larvae can do it in as little as a week. You can hear them eating.”
Up to 15 per cent of global greenhouse gases were caused by decaying food waste, Louise said.
“If it’s eaten by insects, the greenhouse gas amounts reduce massively. And they clean up bio-waste.
“People might worry that maggots seem a bit dirty, but what they’re doing is they’re cleaning… they’re quite good at processing the bad things in waste that we need to get rid of.”
The first year of the trial will focus on commercial food waste, and will be based onsite at the Seagull Centre. Once the processes have been refined, the team will look at making its processing facilities mobile, to avoid having to transport large amounts of heavy waste.
The third year of the trial will investigate whether it is possible to safely process human sewage waste.
“It sounds disgusting but we spend an enormous amount of money drying our sewage sludge and then shipping it to landfill and wasting all the nutrients that are in it,” Louise said.
“We really need to cycle all the nutrients in our waste, in our food waste and our manures and put them back into the soil to feed the plants or put them into animals.”
It is this cyclical idea that sits behind the entire project, she said, finding ways to reuse valuable nutrients. Putting the larvae back into the cycle as animal feed will have financial benefits as well as environmental ones.
“A really interesting thing that we’d like to look at is feeding fish,” Louise said.
“If we can find a way of using the nutrients that we already have and using [the larvae] to feed chickens and fish, then we are not having to import soy or fish meal, which is hugely environmentally problematic.”
However, Louise said sewage-fed larvae would not be used as animal feed.
“There are other things you can do with it. We’re working with Environmental Science Research, which is a government research agency, to work out how to do all this safely and cleanly,” she said.
“We’re also working with students from the University of Canterbury on the products that you can make with them – you can actually make soap with the oil from the larvae, [and] adhesive.”
The trial is being funded primarily by the Ministry for the Environment’s Waste Minimisation Fund, along with a $50,000 grant from the Waikato Regional Council, and $90,000 from the Seagull Centre.
“We’re going back to a natural system. It’s actually going to try and work with nature rather than against it, because when you have a monoculture and all the insects are poisoned, there’s nothing to clean up the mess,” Louise said.
“We just want to try and push a solution that’s circular to avoid wasting all these nutrients that we really need to grow our food and to grow our animals.”
