In an analysis, a team of scientists has come up with ways to use pig manure to generate electricity. A large amount of pig manure, created by thousands of animals in giant hog farms can pollute rivers, poison groundwater and pump out clouds of methane and carbon dioxide. So, finding alternative uses for the slurry - to generate electricity, makes a lot of sense. The problem was that no one has been certain which way of doing it makes the most electricity for the least greenhouse gas production.
Now, according to a report in New Scientist, a Danish team has analyzed the various ways in which firms in that country treat pig manure and use it to generate electricity in systems such as anaerobic digesters or incinerators. In anaerobic digestion, bacteria break down waste material by warming it in an oxygen-free vessel, releasing methane, which is used in gas turbines. Incinerators burns the material to boil water and drive a steam turbine.
The team, led by Trakarn Prapaspongsa at Aalborg University, found that for high-efficiency energy production, anaerobic digestion is the answer to convert pig poo into ‘green’ power. But if minimising greenhouse gas emissions takes priority, the best option was to separate the solid from the liquid waste, dry the solids and incinerates them.