The escalating global water crisis is heightening the imperative for us all to save this precious resource. The dairy industry’s milk processing plants are employing state-of-the-art technologies to recycle and reuse water, and so significantly reduce their need to draw fresh water from external sources.
Pioneering Water Conservation
The 2015 World Economic Forum report cited the global water crisis as the biggest threat that our planet will face over the next 10 years. From droughts in the world’s most productive farming regions to the lack of access to safe water for billions of people, water crises will affect the populations and economies of both the developed and developing nations. In fact, figures from UN-Water suggest that by 2025, two thirds of the world’s population could be living under conditions of water stress, and 1.8 billion people will be living in countries or regions with absolute water scarcity.
The agricultural sector accounts for 70% of global water usage, with industry accounting for another 20%, and domestic usage making up the remaining 10% of demand. As the global population rises, increased agriculture, industry and urbanization are driving the demand for water usage across the board. The urgency of our need to conserve water at every level is obvious. Most of us in developed nations will be aware of local, regional or national initiatives that are encouraging us all to save water. Every sector of agriculture and industry will also need to innovate to find ways of minimizing their demand on the world’s water resources.
Becoming water neutral – the zero water plant
Industry is investing heavily in the development of technologies and processes that can reduce the need for water in industrial processes and manufacturing, and enable efficient water recycling. The dairy processing sector is playing a pioneering role in this drive to become water neutral. Given that milk is approximately 85% water there is huge potential for recovering the water contained in the milk to provide most if not all of the water demands of the milk processing plant. Nothing is wasted, so that fresh water demand and waste discharges are both minimised.
A major global food manufacturer has installed a zero water dairy processing plant in Mexico, which saves 1.6 million litres of water per day. This manufacturer is now investing in another zero water milk plant in the US, which it projects could save some 63 million gallons of water every year. During 2015 the firm’s factories — in every product category, not just dairy — withdrew 41.2% less water per tonne of product than they did 10 years ago. The next goal, for 2020, is to achieve an overall reduction of in water withdrawal of 35% compared with 2010.
Dairy processing leaders in water recycling
In New Zealand, three milk powder plants built by GEA for Fonterra and for Yashili use water recovered from milk evaporation to provide both process and potable water. These water recovery plants have capacities to provide from 800 m3 to 5,000 m3 per day of recovered water, at a 90% recovery rate. The recovery plants are fully automated and require only occasional supervision on top of cleaning after every 48 hours of operation.
Water conservation is a key commitment for Fonterra. During the 2013-2014 financial year, for example, water usage at the firm’s Australian operations was reduced by eight per cent per tonne of production, and by two per cent per tonne at its New Zealand sites. Fonterra’s Darnum site is also water efficient and can reuse water when manufacturing skim and whole milk powders.
Yashili’s latest infant formula plant in Pokeno, for example, draws minimal water from external sources. Thanks to technology provided by GEA, the company extracts most of the water required to operate the plant from the fresh milk that it processes. This keeps environmental footprint and disposal costs low.
A global leader in filtration systems
With decades of industry and technological expertise in the dairy processing sector, GEA is a global leader in the provision of filtration systems that are used to recover and recycle condensate from the evaporation stage of milk processing. Technologies for recycling water that can be used for cleaning, and for other non-product-contact operations in industrial processes are relatively straightforward, according to GEA, which worked with Fonterra to design, equip and construct the latter’s milk powder plants. The condensate, which is known as ‘cow water’, is collected from the evaporation plant, and purified through a high pressure reverse osmosis plant that uses membranes to filter out contaminants and unwanted dissolved substances from the condensate. GEA has installed more than 100 reverse osmosis plants globally.
The recycling process needs additional steps if the recycled water is to be used in the product itself. Carbon treatment is carried out to remove unwanted odours, and UV and chlorine dioxide treatment are used to remove contaminants. Minerals are then added to make the water less aggressive to the plant’s systems. This more complex overall process requires a suitable plant design, into which the additional water processing stages can be incorporated efficiently.
Recycled water that has been treated using these technologies can be purified to meet WHO standards for potable water and so can be used in a wide variety of operations in the dairy plant, such as final flushing, cleaning of tanks and pipework, and even as an ingredient in the finished product. GEA technology includes tanks and piping that will satisfy hygiene requirements for processing the recovered water so that it is clean enough to come into contact with the product.
Even when using state-of-the-art technologies and systems to purify recovered water from industrial processes, it may not always be possible to cost-effectively or efficiently purify all recycled water to standards that will permit its use in processing. Even so, there will probably be some use for this water, whether it is to water gardens or to flush toilets. Every gallon of recycled water that can be reused will lessen the burden of supply from the water utilities.
Not just for milk processing
It is quite feasible from a technology and engineering perspective that all new dairy plants could be constructed to incorporate water saving and recycling technologies that will allow them to derive all their required water from the milk that they process, and reduce the demand from external sources. These technologies can also be deployed in existing plants, after careful study of available sources and potential for reuse within the plant. And while water reuse initiatives are being applied very successfully in the dairy sector, it is feasible that the same technologies could also be applied to other sectors of the food industry that require high volumes of water for processing.
“As water resources are getting scarce, the dairy industry has been in the forefront of conservation efforts,” comments Swami Sundaram, GEA Product Manager, Membrane Filtration. “Since the early 1990s, when the first membrane plants were installed to recover water from evaporator condensate and reuse it, the technology has become a common feature for all new installations. It has also facilitated installation of large production facilities even in water stressed areas such as in the Western United States.”
UN-Water claims that over the last century the global use of water has been increasing at twice the rate of the population growth. The imperative to conserve this valuable resource is therefore becoming ever more acute. GEA is proud to offer its process and engineering expertise as a pioneer in the development of robust, efficient, and environmentally sound technologies, solutions and systems for zero water plants in industrial processes.