17-Year-Old Turns Food Waste Into Biodegradable Paper Towels

A 17-year-old student from California has developed an experimental method to turn food waste into biodegradable absorbent sheets that could potentially be used as paper towels.

The project explores a way to address two environmental concerns at the same time: the large amount of food waste generated every year and the environmental impact associated with disposable paper products.

The research was presented at the International Science and Engineering Fair. It focuses on recovering cellulose, a fibrous material found in plants, from discarded food scraps and converting it into a usable biodegradable material.

How food waste is converted into absorbent sheets

The process begins by drying food scraps and reducing them into smaller particles. The material then goes through acid, alkaline and bleaching treatments designed to remove unwanted components and isolate cellulose-rich fibres.

The recovered cellulose is then combined with pectin, a naturally occurring plant-based polymer. The mixture is formed into thin sheets and subsequently treated with calcium chloride.

Calcium ions help connect charged groups within the pectin, creating a stronger internal structure. This step is important because absorbent materials need to take in liquid while also maintaining their structure when wet.

Absorption versus strength

Laboratory testing showed a trade-off between absorption speed and wet strength.

In some formulations, calcium-based crosslinking reduced absorption by around 20% to 40%. However, the treatment significantly improved the material's ability to remain intact when wet.

Wet strength increased from approximately 0.19 newtons in uncrosslinked material to as much as 0.34 newtons after calcium treatment. The prototypes, which were tested as 5-by-5-centimetre sheets, absorbed approximately 5 to 6 millilitres of liquid per sheet.

The most promising versions had effective pore sizes of around 20 to 30 micrometres. Researchers also tested different sheet weights and concentrations of pectin to study how these factors affected performance.

Could food-waste paper towels be cheaper?

The project also examined the potential economics of producing the material at a larger scale.

The estimated cost could be around USD 2.98 for 100 sheets, compared with approximately USD 3.40 per 100 sheets for the sustainable paper towel used as a benchmark.

However, these figures are only projections and do not establish that the material can currently be produced commercially at that price.

Commercial production would need to account for several additional costs, including collecting and transporting food waste, processing the raw material, chemicals, energy, equipment and quality control.

Another challenge is the varying composition of food waste. Different types of fruit and vegetable scraps can contain different amounts and forms of cellulose, which could make it difficult to produce sheets with consistent properties.

Potential uses beyond paper towels

The technology could potentially have applications beyond disposable paper towels. With additional research and development, materials made from recovered cellulose, plant-based pectin and calcium reinforcement could potentially be explored for wipes, packaging and absorbent mats.

Each application would require different characteristics, including the appropriate combination of strength, softness, stiffness and liquid absorption.

From laboratory prototype to sustainable material

The food-waste paper towel remains a laboratory-stage concept and requires further research, testing and development before it could become a commercially available product.

The project nevertheless demonstrates how discarded plant-based material could potentially be converted into useful biodegradable products. By recovering cellulose from food waste instead of treating it only as waste, the approach points towards another possible route for developing more sustainable disposable materials.