New technologies for sustainable dairies
The dairy industry comprises 13 % of Europe’s food and beverage industry. To ensure its future competitiveness and reduce its environmental impacts, the sector must minimise its use of energy and water and develop its use of renewable energy. This challenge was taken up by the SUSMILK (Re-design of the dairy industry for sustainable milk processing) project, which focused on four different technologies. They comprised heat pumps, absorption chillers, milk concentration units, and solar thermal collectors in combination with biomass pellet boiler for a 24 hour heat supply. Prototypes were built and tested under real conditions in SUSMILK partner dairies and assessed using life-cycle assessment, exergy analysis and economic analysis. The developed heat pump and absorption chiller utilised available waste heat within the dairy to reduce overall energy consumption. Increased sustainability through innovation Researchers also investigated technology for recovering chemicals and water from clean-in-place (CIP) processes. This is a technique that cleans the insides of pipes and process equipment without the need for disassembly. In addition, the usage of wastewater from dairies as raw material for biogas, bioethanol and lactic acid production was investigated. ‘All these innovations can contribute to a decrease in primary energy consumption and greenhouse gas emissions,’ states Dr Christoph Glasner, the project manager of SUSMILK. ‘They were evaluated and placed in a green dairy model, which will help dairies to implement more resource efficient technologies. The model showed great potential for improving even the best dairies and its wide-scale usage will bring major benefits throughout Europe.’ A typical dairy uses a lot of heat throughout the processing with potentially some waste heat losses. SUSMILK therefore created a heat pump with a maximum output temperature of 120 °C and capable of recovering 80 % of the waste heat. A new absorption chiller was also developed for the cooling needs of the dairy that exploits potentially available waste heat. Spreading the message Pre-concentration of milk using ultrafiltration and nanofiltration units allowed it to be processed without the need for large amounts of energy. This will also help to reduce transportation costs and the sizes of tanks and machinery in the dairy, while increasing the efficiency of production processes for cheese, yoghurt and other products. ‘Key results were the prototypes themselves and the green dairy model, which led to guidelines for the dairy industry,' explains Dr Glasner. Furthermore, an online calculator was developed to give dairies the opportunity to estimate their own potential for energy savings, milk concentration and improvements to their CIP system. Another successful project outcome is the GreenDairyNet, an open innovation platform that brings together food researchers, technology providers and dairy producers. With SUSMILK’s help, the dairy industry in Europe is expected to save energy and water by integrating optimised technology. Looking back over the project’s achievements, Dr Glasner concludes ‘each technology developed was a piece in the puzzle towards a more sustainable dairy processing sector.’
Keywords
Milk processing, SUSMILK, clean-in-place, green dairy, pre-concentration
