[Australia] Pig effluent could be used to grow algae or seaweed that is fed back to pigs as part of a closed-loop system for intensive piggeries.
- Researchers prove pig poo can be used to help grow algae
- Algae can be fed back to pigs or help to produce methane to generate electricity
- Pig manure can also help reduce use of costly fertiliser
Researchers at Murdoch University’s Algae Research and Development Centre have proven they can grow some aquatic species on untreated pig waste, despite the high concentration of ammonium.
Centre director Dr Navid Moheimani said algae grew naturally in harsh conditions and was a potentially protein-rich source of food for pigs and other animals.
“The algae normally contains one third carbohydrate or sugar, one third protein and one third lipid [fat],” Dr Moheimani said.
“A lot of algae do not produce a lot of cellulose, which means they are very easily digestible.
“The other very important thing for us is to find out what sort of other bacteria like pathogens are coming in with the feed and so we’re also testing that.”
Even if the algae was too contaminated to use as a feedstock, Dr Moheimani said it would greatly increase the production of methane in on-farm biogas systems.
Biogas systems capture methane from manure, turn it into electricity and export it to the national grid.
At Blantyre Farms near Young in New South Wales, they paid $1 million three years ago for such a system.
Edwina Beveridge, who runs the 25,000 pig operation, said her investment paid for itself in two and a half years.
“It used to cost us about $15,000 a month for electricity and gas and now we get paid about $5,000 a month for selling excess electricity,” she said.
The farm is one of seven piggeries sharing $7 million a year from the Commonwealth’s Emissions Reduction Fund for its greenhouse gas abatement through methane capture.
“So not only did the biogas project have good economical sense, it’s good for the environment as well,” she said.
“Who would think a pig farmer could also be a renewable energy supplier?”
Refined manure helping to reduce fertiliser use
Despite producing just 0.4 per cent of Australia’s greenhouse gas emissions, the pork industry has been at the forefront of research into carbon abatement and finding other profitable uses for effluent.
Investments by Australian Pork Limited and the Co-operative Research Centre for Pork are yielding benefits for small and large piggeries and potentially for Australia’s broad acre crop producers.
It used to cost us about $15,000 a month for electricity and gas and now we get paid about $5,000 a month for selling excess electricity.Edwina Beveridge
In the West Australian wheat belt, early field trials showed crops grown with a combination of manure and synthetic fertilisers performed better than those using only fertilisers.
Dr Sasha Jenkins said wheat was grown with pellets of refined pig manure applied with varying rates of fertilisers in a conventional air seeder.
“Basically I think about 25 per cent of their costs are going into synthetic fertilisers, so if they utilise the manure, the refined manure product, we’re hoping to reduce the amount of synthetic fertiliser they use,” she said.
“That’s obviously going to reduce the operation costs of the industry and increase their productivity.”
The field trials found big differences in the amount of greenhouse gases released by the treated soil to what would occur in Europe.
According to Australian Pork Limited’s manager for environmental research and development, Janine Price, those findings have been groundbreaking for Australia, which has until now relied on European models.
“That’s extremely significant because that base-line data that’s been generated from that project and other projects goes into the Australian accounts inventory,” she said.
“So we can now actually say this is what’s going on in Australian feedlots, in piggeries, on broiler farms, on egg layer farms. That’s now going into the national accounts.
“It’s also being upgraded in all our industry models so when we run our greenhouse calculators and our nutrient balance calculators we have up to date data into that.”
Photo: The pork industry is at the forefront of research into carbon abatement and finding other profitable uses for effluent.
View original article at: Pig manure could help grow feed for piggeries, cut greenhouse gas emissions, research shows