Background The production of potato starch uses large amounts of water and energy. Increasing environmental requirements along with the need to remain competitive are encouraging potato starch factories to find alternatives to disposing of fruit water. In the EU, where around half of the world’s potato starch is produced, the Sixth Environmental Action Plan and the recent Action Plan on energy efficiency aim to both increase energy efficiency and encourage the more efficient use of natural resources. The potato starch industry consumes around 1,000m3 of natural gas per hour and discharges in wastewater the equivalent of 2.9 million people’s wastewater. Objectives The project aims to reduce the environmental impact of the potato starch industry by developing an environmentally and economically sustainable production of potato protein at industrial scale, thereby reducing consumption of water, discharge of wastewater as well as increase the quality of the product – potato protein. By transforming fruit water to high-value protein, Karup Kartoffelmelfabrik can take steps towards producing fertilizer concentrate and biomass for energy production, as well as towards treating process water for reuse in the production process. Results This LIFE project has enabled the beneficiary to develop a process for recycling its wastewater. The water is rich in organic matter, and the project aimed to extract the protein contained for industrial use and animal food production. The process developed removes at least half of the nitrogen from the wastewater. The waste product, which contains phosphorus and potassium, is then dried so that it contains just 10% water and can be sold as fertilizer sludge. The beneficiary built a new factory and achieved two main improvements: • A better heating and heat exchange system for the process, along with better decanting and drying of the end product; and • A system for separating the potato proteins into fractions. The project experienced excellent energy savings of around 60%. Other results include a 55-60% reduction in nitrogen discharge compared to traditional starch production plants, and a 40% reduction of water consumption. In economic terms, the total energy and electricity costs have been calculated at € 0.11 per kg of protein, compared to figures for the starch industry based on EU data from 2001 amounting to € 0.34. At the site, the fruit water is transported directly from the starch factory through pipes to the protein factory where acid is added. With heating of the water, the protein precipitates and is separated in a decanter. The factory also functions as a demonstration site and serves to show other interested parties how energy saving and environmental improvements can be achieved. Karup Kartoffelmelfabrik is also aiming to produce a protein that has a low solanine content. Solanine is a toxic substance in potatoes that have been exposed to sunlight, making them turn green. The company is investing in a demonstration unit that extracts a large percentage of solanine for the protein. This unit will enable the protein to be sold to a wider customer base.