Waste products from New Zealand's food processing industry – such as potato scraps and grape skins – could be transformed into high-value soil conditioners and animal feed, according to new research.

University of Canterbury environmental science professor Brett Robinson is spearheading a project that aims to turn biological waste products, which can contaminate waterways and are dumped at great expense into landfills, into new products that could deliver a $1.6 billion boost to New Zealand's economy.

'Each year, New Zealand sends 2.2 million tonnes of untreated industrial food processing biowaste into landfills,” says Brett.

'This costs $270 million a year and results in greenhouse gas emissions equivalent to eight million tonnes of carbon dioxide annually.”

Circular economy

Transforming this biowaste into high value products, such as soil conditioners and nutritionally balanced animal feeds, would help reduce New Zealand's carbon emissions and bring economic and environmental benefits.

'We want to create economic and environmental value from biowastes by ensuring the nutrients they contain are harnessed to improve our soils and feed our animals rather than degrading our waterways and contaminating soil.

'Our overarching goal is to reuse and recycle our waste, helping to make our agricultural economy more circular and our food production more sustainable in the long-term.”

Professor Robinson estimates the potential economic benefit of the research is more than $1.6 billion a year.

This includes reduced disposal costs, new product sales and reduced reliance on imported products like phosphate fertilisers and PKE, which costs about $300 million a year.

Reducing contaminants in the environment and food supply would also enhance New Zealand's reputation in overseas markets, says Brett.

Repurposing waste

The project team plans to develop new microbiological (using bacteria and fungi) treatments that can be used to turn waste products such as grape marc – stalks and skins that are a by-product of wine production – into balanced animal feed that improves animal health and wellbeing.

Artificial intelligence methods would be used to select which microbes can transform specific biowastes efficiently.

New Zealand's milk processing industry produces nearly 800,000 tonnes of solid biowaste and 190 billion litres of liquid effluent annually.

Brett says bioreactors at milk processing plants could transform this waste into a valuable soil conditioner instead of it being disposed of on nearby land.

He says potato waste is also an issue, with 30 per cent of potatoes going to waste, when the peel, slivers and rejects have potential to be transformed into useful animal fodder. The seafood, meat and horticulture industries also produce significant waste streams.

Locally sourced

Brett says providing locally sourced animal feed and soil conditioners would make New Zealand more self-sufficient, and would increase soil carbon, reducing the need for expensive fertilisers.

'This research is a critical part of New Zealand's agricultural future as we face increasing competition from countries who are producing synthetic meat and milk. We need to show that we can produce high quality meat and milk in a sustainable, clean environment.

'We want to work with farmers to find the best outcome for both our economy and the environment and we're engaging with the industry to find the best solution.”

The UC-led project is in collaboration with scientists at Manaaki Whenua Landcare Research, Plant and Food Research and Lincoln University.