Researchers on a global scale have been interested in using biopolymer fibres in concrete to improve specific properties of the material. The exploitation of the biopolymer fibres, feathers, can be beneficial to the environment by lowering the amount of waste produced and disposed by the poultry production industry.
On an international level, the poultry industry produces a large amount of waste, with about a third of each chicken being discarded and only two-thirds being sold for food consumption. In addition to being wasteful, this production has a negative carbon impact on the environment because incineration is the most popular method for disposing of such materials.
Data gathered from producers in Malta shows that approximately 70,000 tonnes of waste is incinerated per month. This is the resultant amount of waste from slaughtering approximately 6,500 chickens per day, amounting to 1.2 million chickens per year.
By minimising waste in the chicken production industry and reducing costs with the replacement of synthetic reinforcing fibres in the concrete matrix, a circular economy can be created by attempting to employ these by-products in construction materials, another industry with a very high carbon footprint.
The poultry industry produces a large amount of waste, with about a third of each chicken being discarded
A study, authored by Prof. Ruben Paul Borg and Elisabete Spiteri Cornish from the University of Malta’s Faculty for the Built Environment and Prof. Everaldo Attard from the Institute of Earth Systems, and supported by the Malta Council for Science and Technology (MCST), investigated the potential use of waste biopolymer feather fibres in cement-based materials and biochar as fertiliser.
Waste biopolymer feather fibres were assessed, with different fibre lengths and with varying fibre volume percentages. The researchers developed an operating procedure, including washing and shredding, to transform the feathers into a product ready for inclusion in concrete and mortar.
An advanced experimental investigation was conducted to assess the performance at the different stages of the concrete production cycle from the fresh state when it is cast, to the hardened and long-term durability properties.
Its fresh properties were determined with respect to different tests, whilst the early stage crack behaviour was also assessed together with the mechanical properties, durability and environmental life cycle impact.
The results showed that bio-polymer feather fibres significantly improved the properties of concrete. The concrete had better plastic shrinkage, compressive strength, and improved ductility. Insulating panels with bio-polymer feather fibres were also produced, to be used in a wide variety of building products.
The study also investigated the potential of converting meat and bone meal waste into a soil amendment. Results show that this type of biochar helps in improving plant growth and performance.
Sound Bites
• Concrete is the second most consumed material in the world, after water. Concrete is necessary and increasingly used. Its large environment impact is due to the large carbon footprint of the binder: cement. It also uses massive natural resources. More sustainable concrete can be produced by using industrial by-products and recycled waste.
• Meat and bone waste is not fit for human consumption but it is rich in protein (40-50%), fat (10-15%), calcium (8-12%), phosphorus (4-6%) and other minerals such as potassium, sodium, magnesium and iron. Some companies convert this into pet food, but this raised safety concerns. Biochar production is a way to incinerate the waste and turn into a useful, safe product.
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DID YOU KNOW?
• The global poultry production industry creates a total of 68 billion tonnes of waste per year. Poultry waste is taken to the incinerator to be disposed of safely.
• Feathers are mostly made of keratin, similar to the protein found in human hair and nails.
• Concrete is brittle and cracks. Therefore different types of fibres are introduced to mitigate this and improve its tensile properties, including ductility.
• When organic material is burnt in the presence of oxygen, only minerals remain in the ash. In the absence of oxygen, carbon and other minerals remain in the char.
For more trivia, see: www.um.edu.mt/think.