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Even pig poop is useful!

Posted on 11 October 2016.

Ellie Fini, an American engineer, has discovered that pig manure can be used to replace oil as a binder in ecological asphalt.

Worldwide 163 billion liters of liquid pig manure are produced annually – the challenge is finding recycling options.

The idea of eco-friendly durable asphalt using pig manure germinated in the head of an American engineer and professor in Greensboro, Ellie Fini, along with her team at the Agricultural & Technical State University of North Carolina.

Worldwide, 163 billion liters of pig manure needs recycling

Their discovery is simple: there is an oil in the liquid pig manure produced by intensive farming. Once extracted, this oil can act as a binder which, mixed with gravel and sand, for example produces asphalt that can be used to build roads.

This "bio-adhesive" binder has a number of advantages. And the first of those is it means it’s possible to avoid using oil-based hydrocarbons.

The second is making not only ecological asphalt, but also one that is more durable and more resistant. Which in the United States, where the car is king, is a really strong argument... Especially since it costs only 56 cents per gallon to process (a gallon is 3.8 liters).

And finally it limits water contamination - one of the consequences of the open manure lagoons that can be seen everywhere - especially in the United States.

The discovery made by Ellie Fini and her team opens up interesting perspectives for making use of the 163 billion liters of pig manure produced annually worldwide!

In the wake of their discovery, in February 2013 Ellie Fini, Mahour Parast and Daniel Oldham set up a company called the Bio-Adhesive Alliance. Crowned with numerous awards since then, their invention received the approval of the very serious National Science Foundation. Bio-Adhesive Alliance now wishes to develop its bio-adhesive, dubbed the PiGrid, for use in asphalt but also for roofing and sealing applications.

An alternative binder

Other methods of recycling slurry and manure are currently being studied: one of them is to reduce the amount of ammonia in the manure to make it less harmful than conventional fertilizer; another is to extract the methane for use as an energy source. A great circular economy loop - from farm to farm!