Cow manure transformed by researchers into manufacturing-grade cellulose

Tanya Weaver Wed 7 May 2025

Collected at: https://eandt.theiet.org/2025/05/07/cow-manure-transformed-manufacturing-grade-cellulose-new-study

Researchers have extracted cellulose strands from cow manure and turned them into manufacturing-grade cellulose for use in everyday items such as surgical masks and food packaging.

Cellulose is one of the world’s most commonly used manufacturing materials and can be found in items including cling film, paper products, textiles, foods and pharmaceuticals. 

While cellulose can be extracted organically from plants, it is more often than not produced synthetically using toxic chemicals.

Cellulose also exists in the manure of grass-eating animals, such as cows, because they do not fully digest plant material.

Manure is a growing problem worldwide, as farmers are producing more manure than they can legitimately use as fertiliser.

Research in 2019 estimated that the amount of animal waste is due to increase by 40% between 2003 and 2030 to at least five billion tons. 

Looking to enable a true circular economy, a research team from University College London (UCL) and Edinburgh Napier University decided to experiment with this waste product from the dairy farming industry. 

In a new study, they used the cellulose extracted from manure as a raw material in their ‘pressurised spinning’ manufacturing process. 

Pressurised spinning or pressurised gyration was first invented in 2013 by a team from UCL Mechanical Engineering led by Professor Mohan Edirisinghe.

This manufacturing technology uses the forces of pressure and rotation simultaneously to spin fibres, beads, ribbons, meshes and films from a liquid jet of soft matter. 

Professor Edirisinghe, senior author of the study, said: “Our initial question was whether it could be possible to extract the tiny fragments of cellulose present in cow manure, which is left over from the plants the animals have eaten, and fashion it into manufacturing-grade cellulose materials.

“Extracting the fragments from dung was relatively straightforward using mild chemical reactions and homogenisation, which we then turned into a liquid solution. But when we tried to turn the fragments into fibres using pressurised spinning technology, it didn’t work.”

Through a process of trial and error, the research team discovered that using a horizontal rather than vertical vessel containing surface nozzles and injecting the jet of liquid into still or flowing water caused cellulose fibres to form. 

They then changed the consistency of the liquid to create other forms, each of which have different manufacturing applications.

Edirisinghe said: “We’re still not quite sure why the process works, but the important thing is that it does. It will also be fairly easy to scale up using existing pressurised spinning technology, the vessels for which were designed and built in the UCL Mechanical Engineering workshop.”

The researchers claim that this technique – called horizontal nozzle-pressurised spinning – is an energy efficient process in that it does not require the high voltages of other fibre production techniques such as electrospinning.

While the research team are hopeful that existing pressurised spinning machines can be adapted to the new process, the greater challenge will be the logistics of sourcing and transporting cow dung.

Yanqi Dai, first author of the study from UCL Mechanical Engineering, said: “Dairy farm waste such as cow manure is a threat to the environment and humans – especially through waterway pollution, the release of greenhouse gases into the atmosphere when it decomposes and the spread of pathogens. It is also often a burden on farmers to dispose of properly.

“Horizontal nozzle-pressurised spinning could be a huge boost to the global dairy farming industry by putting this problematic waste product to good use and perhaps creating a new source of income.”

The study has been published in The Journal of Cleaner Production.