By DOUG GRAVES

Ohio Correspondent

COLUMBUS, Ohio — No pleasant conversation likely comes from cow or elephant dung, but researchers say this yucky material turns out to be an excellent source of cellulose for paper manufacturing.

Researchers presented findings this spring at the 255th National Meeting & Exposition of the American Chemical Society (ACS) in New Orleans, which featured more than 13,000 presentations on a wide range of science topics. ACS, the world’s largest scientific society, is based in Columbus, Ohio.

The idea for this manure project had its start in Crete, where Austrian Dr. Alexander Bismarck noticed goats munching on summer-dry grass in the small village where he was vacationing.

“I realized what comes out in the end is partially digested plant matter, so there must be cellulose in there,” said Bismarck, a Ph.D. at the University of Vienna. “Animals eat low-grade biomass containing cellulose, chew it and expose it to enzymes and acid in their stomach, and then produce manure.

“Depending on the animal, up to 40 percent of that manure is cellulose, which is then easily accessible. So, much less energy and fewer chemical treatments should be needed to turn this partially digested material into cellulose nanofibers, relative to starting with raw wood.”

After working with goat manure, Bismarck and several of his graduate students took a look at dung from horses, cows, and eventually elephants. He realized the supply of raw material is substantial, as parks in Africa are home to hundreds of elephants that produce tons of dung every day, and enormous cattle farms in the United States and Europe yield mountains of manure.

“In the U.S. where there are plenty of farm animals such as cows, ‘upcycling’ manure into paper products could be a cheap and environmentally sound method to get rid of this pervasive agricultural waste,” Bismarck explained.

The researchers treat the manure with a sodium hydroxide solution; this partially removes lignin, which is a class of complex organic polymers that form key structural materials in the support of tissues of vascular plants and some algae. The lignin can also be used later as a fertilizer or fuel. The sodium hydroxide solution also removes other impurities, including proteins and dead cells.

“To fully remove lignin and to produce white pulp for making paper, the material has to be bleached with sodium hypochlorite,” Bismarck said. “The purified cellulose requires little if any grinding to break it down into nanofibers in preparation for use in paper, in contrast to conventional methods.”

Assisting Bismarck in this research is Andreas Maultner, also of Austria.

“You need a lot of energy to grind wood down to make nanocellulose,” Maultner said. “But with manure as a starting material, you can reduce the number of steps you need to perform, simply because the animal already chewed the plant and attacked it with acid and enzymes.

“You inexpensively produce a nanocellulose that has the same or even better properties than nanocellulose from wood, with lower energy and chemical consumption.”

According to Bismarck, members of his team are working with an industrial consortium to see if the dung-derived nanopaper could be used as reinforcement for polymer composites or filters that can clean wastewater before it’s discharged into the environment.

And, yes – the nanopaper could be used to write on. The resulting paper is also sturdier than conventional paper such as newspapers, and can be produced with consistency.

But there’s more. Researchers are also investigating whether the process can be made even more sustainable, by first producing biogas from manure and then extracting cellulose fibers from the residue. Biogas, which is mostly methane and carbon dioxide, can then be used as a fuel for generating electricity or heat.

There are other uses for animal waste. Last year, scientists from China used panda poop to make facial tissues. In India, a mud and cow manure paste is often applied to the floors of rural homes, as the mixture forms a waterproof layer that helps insulate the houses from heat. The same nation has learned the smoke from burning cow dung repels insects, including mosquitoes, leading to the use of it as a pesticide in some areas.