Dairies produce a significant amount of waste (milk residue and wastewater) when cleaning and processing. About 2.5 liters of waste is generated per liter of milk produced. To top it off, dairy is the second-largest agricultural sector following vegetables. There are over 12,000 milk processing and production sites across the European Union member states alone. In 2018, the EU produced 172.2 million tons of raw milk.
Since the demand is expected to increase and all industries, including dairy, are facing pressure to become as sustainable as possible, researchers have developed a way to turn the waste streams from dairies into valuable products: bioplastics, phosphate-rich fertilizer, and even clothing.
The European Commission stresses that food systems are still one of the key drivers of environmental degradation and climate change. Dr. JJ Leahy, a chemist at Ireland’s University of Limerick, is leading a project called REFLOW, which aims to retrieve phosphorous for fertilizers from dairy-processing wastewater. He said:
We recognized that the dairy sector was one of the biggest sources of organic waste.
We want to produce a range of phosphorous-rich fertilizers and test them against conventional phosphorous mineral fertilizers.
Phosphorous is vital for plant health and growth, but current commercial fertilizers obtain the mineral by mining it from phosphate rock, which is a non-renewable resource.
Furthermore, the phosphorus-rich effluent from dairies’ wastewater can cause problems in lakes and rivers. The excess of nutrients causes some plants and algae to thrive, resulting in eutrophication – a condition of little oxygen and light in the water for animal species to survive.
A different project based in Ireland called AgriChemWhey is developing another way to use dairy waste – but from Whey production. In the making of whey powder (popular among athletes as a protein supplement for muscle growth), the whey protein and solids are extracted from the dairy waste leaving whey permeate (the liquid) behind. To make use of the whey permeate instead of just discarding it, the researchers developed a biotechnological process to transform it into polylactic acid, which is a bio-based plastic that can be used in fabric and packaging.
Dr. Bill Morrissey, leader of the project, said:
The polylactic acid produced from the feedstock we use is more sustainable than current methods. It is a second-generation feedstock – a byproduct of a byproduct. From a sustainability point of view, it ticks a lot of boxes. This is very important in terms of climate change.
As a bonus, these projects help to safeguard the rural way of life for family-owned farms as farming space globally becomes more constrained. Being able to convert their waste into a valuable resource is an additional source of income for the people. So, they don’t have to move to cities in search of an opportunity to make more money.
