Modern water treatment will grow in importance for residue-free fresh water in the future
The United Nations (UN) have found that water consumption has been rising by approximately one percent annually since the 1980s. This rise is fueled by growing populations, socioeconomic developments and the changing of consumption habits.
Worldwide water demand will continue rising at this level until 2050 – increasing to 20 to 30 percent above today’s water consumption levels. The UN also expects climate change to widen the gap between supply and demand. This will even affect regions where water shortages had been hitherto unheard of. For example, a number of dry summers in Germany have drastically reduced the water table.
Water-product relationship grows as the center of attention
Richard Clemens, Managing Director of the VDMA Food Processing and Packaging Machinery Association and the Process Technology trade association, summarized the upcoming conditions: “We can expect falling availability with large increases in global demand, meaning a more critical evaluation of water origin and the water-product relationship. For that reason, the topics of water treatment and recycling up to disposal, as well as the hygienic design contributions for water consumption reduction will increasingly be made the focus of our attendance at drinktec.”
Clemens’ assessment is based on solid reasons: First, every liter of water and wastewater generates costs, which are expected to rise. Second, global players want to create standardized production methods that incorporate water-use into the design processes. Third, new sources must be found and developed into fresh water in response to water scarcity and deep water protection needs. Fourth, water is an aspect of corporate social responsibility, which has affected consumer purchasing decisions and the approval processes for both new and expansion investments for a long time. For example, look at Mexico: A 65-percent complete brewing operation owned by the US company Constellation Brand was prohibited from beginning operations because the brewery would draw off water desperately needed by the region.
Clean water demands are on the rise
Simultaneously, demands for residue-free water to be utilized for bottled water, brewing water, mixing water and dilution water are growing. Residue-free water means state-of-the-art analytical systems cannot find any undesired substances in the fresh water, regardless of the water source. This is an immense challenge, as professor Stefan Schildbach, from the Food Technology department of Fulda University of Applied Sciences, explains: “We are living in an era dominated by people. Almost no natural resources exist that are undisturbed by anthropological influences, and that particularly applies to water.”
Just a few examples of this are blood lipid reducers, painkillers, antirheumatics, analgesics, roentgen contrast mediums, plastic particulates and hormones found in the water table. New or stricter thresholds like those covering uranium bromate and perfluorinated compounds are also being introduced.
Today, the “residue-free” demand is being achieved technologically more and more via membrane processes. As well, other technologies like ion exchangers and lime precipitation serve their purposes. An exchanger is an appropriate method for removing individual ions like nitrate or uranium. Lime precipitation is a low-cost method for the appropriate raw water composition that produces little wastewater. Selective adsorbers are also implemented that can target and remove ions such as arsenic.
RO plus EDI – a fascinating alternative
However, the trend is moving firmly toward membrane separation via ultra- or nanofiltration and reverse osmosis (RO). These processes quantitatively separate nearly all organic and inorganic substances, and then bring them to the desired quality level for fresh water via high-purity salts or blending water according to technological or internal company guidelines.
Dirk Scheu of Krones AG states that a new and interesting variant of this is the combination of reverse osmosis and electrodeionization (EDI). Above all, says Scheu, this applies to table water or alkaline water production, which is becoming more attractive worldwide as part of an acid-based diet. In EDI processes, the raw water substances are separated out via an ion-exchange resin and ion-selective membranes to a value smaller than 0.1 mg/l.
To summarize the advantages, Dirk Scheu says that: “Up until this point, necessary water clarity could only be achieved via two consecutive reverse osmoses. Now, electrodeionization has eliminated the need for this second step. This means much lower electricity consumption overall, as there’s no need for a high-pressure pump.”
Simultaneously, there is a lower consumption of antiscalants and chemicals for adjusting the alkaline water pH levels. Moreover, the expensive high-purity salts must be dosed more precisely, lowering this cost block. Last but not least, the DC voltage required for continuous regeneration can be generated ideally via photovoltaics, making possible the climate-neutral 24/7 ultrapure water levels.
1 = ultrafiltration
2 = activated carbon filter
3 = reverse osmosis
4 = EDI (electrodeionization)
5 = preparation and addition of minerals
6 = ozonization and distribution
© Krones AG
In these ways, modern water treatment has grown more complex than ever before. Furthermore, the coming challenges are sure to make it even more complicated. At drinktec 2021, discover the latest research results and experience water-management and fresh water treatment solutions at work. Many other relevant aspects of water as a resource will be presented firsthand to the international brewing, beverage and liquid food industries at the world’s leading trade fair, drinktec, from September 12 – 16, 2022. Want to showcase your innovations? Join us at the next drinktec.
