Dairies are the main economic drivers in rural areas of Europe . However, they produce significant cleaning and processing waste. Wastewater and milk residues, which are normally disposed of, are now being turned into new products such as phosphate-rich fertilizers and bioplastics.
The EU produced 172.2 million tonnes of raw milk in 2018 and demand is expected to increase in the coming years, especially for export. The regional and international population depends on dairy products, but these are part of the food systems that have a great impact on the planet .
According to the European Commission, “food systems remain one of the main drivers of climate change and environmental degradation.” Its “Farm to Fork” strategy, unveiled in May, aims to modify the region’s food system to deliver environmental, health and social benefits and “ensure that the recovery from the COVID-19 crisis places us in a sustainable way “.
One way to do this is to convert waste streams into value-added products . The dairy sector is the second largest agricultural sector in the European Union after vegetables and horticultural plants, with more than 12,000 milk production and processing plants in the member states. For every liter of milk produced, about 2.5 liters of wastewater are generated.
“We recognized that the dairy sector was one of the largest sources of organic waste,” said Dr JJ Leahy, a chemist at the University of Limerick in Ireland Leahy is leading a project called REFLOW, which aims to recover phosphorus from wastewater from dairy processing .
If not properly treated, the phosphorous-rich discharge can cause problems for downstream aquatic organisms. Problems include eutrophication, in which excess nutrients make algae and plants thrive, but leave little light and oxygen in the water for animal species.
“We want to produce a range of phosphorus-rich fertilizers and compare them to conventional phosphorus mineral fertilizers,” said Dr. Leahy.
Commercial fertilizers tend to obtain phosphorus (vital for plant growth and health) from phosphate rock mined, a non-renewable resource.
sewage water
REFLOW, which started in 2019, is developing techniques to remove phosphorus at different stages of the wastewater management process. The pan-European project is based in Ireland, which has a large dairy industry.
Currently, wastewater is treated in a treatment plant, where it is converted into a denser sludge through chemical processes to reduce the volume to be eliminated. REFLOW wants to take advantage of biological techniques to turn wastewater into sludge, so that fewer chemicals are required. “The next step would be to take this, incinerate it and produce an ash,” Dr. Leahy said.The ash could be used as a fertilizer or as a source of calcium phosphate, as a mild fertilizer or even in medical supplements.
Converting the original mud to calcium phosphate adds costs, says Dr. Leahy, so they are studying which products work best in each country. For example, in the Netherlands, where farmers already export phosphate derived from dairy farms in manure, sewage ash could be more economically viable as it would be lighter and therefore cheaper to transport. In Ireland, sludge, proven for its properties and efficacy in plant cultivation, could simply be spread on the ground, replacing commercial products.
Finding sustainable uses for dairy waste is increasingly important as demand for milk grows. In Ireland, in the last year alone, demand for milk has increased by 50%, says Dr. Bill Morrissey, program manager for the AgriChemWhey project, which is exploring how to turn dairy waste into new products.
Six years ago, Dr Morrissey and his colleagues at Glanbia, Ireland’s largest dairy processor, realized, as the demand for dairy increased, that they needed to manage this growth sustainably and that one of the main obstacles it was dairy waste.
Whey permeate
Whey from cheese making now forms the backbone of Glanbia’s sports nutrition section. Whey proteins are predigested, easily absorbed and promote muscle growth , something highly demanded by athletes. However, once the whey protein and solids have been extracted from the dairy waste, the whey permeate (a liquid) is left behind.
Glanbia worked with several research partners to develop a biotechnology process that transforms whey permeate into polylactic acid, a bio-based plastic , which could be used in packaging and fabric, for example.
Its pilot facility can handle about 10,000 liters of whey permeate, but with the new industrial facility, the project is targeting 25,000 tons.
“The polylactic acid produced from the raw material we use is more sustainable than current methods,” said Dr. Morrissey. “It is a second generation raw material, a by-product of a by-product.” From a sustainability point of view, he says it does many things. “This is very important in terms of climate change.”
The company is partially owned by the Sociedad Cooperativa de Glanbia, which is made up of agricultural cooperatives and farmers who benefit from this additional income stream.
“It allows us to manage sustainable disposal, but it also adds value to our farmers’ milk and supports family farms, ” said Dr Morrissey. Irish agriculture comprises many relatively small farms (around 100 cows per farmer), many of which are family-owned and passed down from generation to generation, he says. According to the Irish Statistical Office, of the 137,500 farms in Ireland, 137,100 are family-owned. In their view, the projects on these farms safeguard the rural way of life as global agricultural space becomes more limited.
According to Dr Morrissey, this offers an incentive for people to stay in rural areas, rather than move to cities in search of opportunities, something that is not unique to Ireland. “That is the great part of this project for me: this is a project that can be replicated around the world.”
ArtÃculo original
This article was originally published in Horizon, the EU Research and Innovation Magazine
