The water-energy nexus

Tuesday, 02 February, 2016

The water-energy nexus

Increasing output while reducing consumption of water is challenging the beverage and brewing industries.

Water is the most important basic ingredient for the brewing and beverages industry. But that’s just part of the story. In the production processes, water fulfils many other functions — either as process water, an energy carrier or in cleaning operations. Water demand and water consumption is therefore correspondingly high. For this reason in the production of beverages and liquid food the emphasis is more and more on a holistic consideration of the way resources are consumed. Economic factors, but also image concerns, in relation to sustainable production, play an important role.

For the manufacturers of bottling and packaging machinery, too, economical use of energy and resources is becoming an ever more powerful commercial argument, important not only as regards a company’s own internal processes, but also in terms of its external image, ie, towards its customers. Themes such as reduced water consumption, the use of process heat, closed-loop production processes, water quality and the use of efficient components are all exercising minds in the industry. Continuing to increase output while reducing consumption of resources — that is a goal for the future.

In the opinion of Richard Clemens, managing director of the VDMA Food Processing and Packaging Machinery Association (Fachverband Nahrungsmittelmaschinen und Verpackungsmaschinen), efficient resource and energy management has not yet penetrated all corners of the beverages and food industry, neither in Germany, nor in the markets worldwide.

Residue-free water

Just why the resource of water is attracting so much attention is explained by Dr Karl Glas, of the Working Group on Water Technology at the Technical University of Munich. He identifies four reasons:

  • Every litre of water and every litre of wastewater costs — and those costs are rising.
  • The multinationals want to standardise production worldwide. And as part of that, the water used has to meet very rigorous standards in terms of quality and technology. The key word here is ‘water design’.
  • How carefully a company uses resources has for some time been influencing consumer decisions on whether to buy or not, and it is very much a factor in authorisation procedures for new and follow-on investment.
  • There are increasing calls for ever cleaner, residue-free water for use in table water and for brewing, mixing or diluting. And residue-free means: no undesirable substances detected with modern analytical methods, regardless of the source of the water. This is an immense challenge in a time when even groundwater can contain traces of statins, painkillers, anti-inflammatory drugs, various analgesics, X-ray contrast media and hormones.

Currently, the demand for residue-free water is largely met through the use of membrane processes such as ultra- or nanofiltration, and through reverse osmosis.

Other applications are also using membrane processes such as wastewater processing, deaeration of water and ensuring the biological quality of water.

Dirk Scheu from Krones AG observed: “This is prompted by the problem of secondary products that can arise during chlorination and that during ozonisation bromide changes to bromate. The WHO has now reduced the limit value here to 0.01 mg/L, but many international companies are adopting much more rigorous standards. Ultrafiltration, with its log rate of 6, can gain ground here. The producers then either don’t have to sterilise any more or they only need to treat the headspace of the bottle with ozone. As a result the danger of bromate formation is correspondingly reduced, and that’s more sustainable.”

Resource recycling calls for optimisation across all areas

When it comes to water recycling, there are basically two ways: in the first the water is collected and sorted according to its pH content or degree of pollution, and then re-used in similar applications. The second way is what’s known as the ‘end-of-pipe’ solution. All the wastewater is collected in a central point and treated anaerobically. The biogas this generates can be used to cover around 20 to 30% of the energy consumption of a brewery. Also possible would be a downstream zero-liquid discharge stage which would enable around 95% of the volume of wastewater to be re-used in production.

Theoretically, even the water in the zero-liquid discharge stage could be treated to reach process water quality.

However, there is an overriding problem here: the more frequently the water is recycled, the more energy is needed. So one resource is saved while perhaps another is being consumed. In order to really get to grips with the issue of resource recycling, the approach has to encompass all areas; many cogs from the many different disciplines all have to fit smoothly together.

Save the date

In September next year, drinktec, the “World’s Leading Trade Fair for the Beverage and Liquid Food Industry”, will be highlighting the whole theme of water and energy management. Approximately 1600 exhibitors from all over the world will be presenting sustainable solutions in this field.

All the relevant areas in the production of beer, beverages and liquid food will be covered at drinktec 2017. Systems for water treatment will be found alongside concepts for the use of renewable energy in breweries. And visitors will be able to find out about a hot-filling process in which cooling energy is recycled for use in production. Highly efficient systems for generating biogas, including membrane separation of the CO2 contained within the gas to produce bio natural gas, for use in standard burners and motors, or for feeding into the gas grid will also be covered.

From 11–15 September 2017 in Munich, drinktec will be highlighting the technology that makes sense today and tomorrow, and the many ways in which this technology keeps coming up with answers as to how to balance economics, the environment and entrepreneurial initiative.

Image credit: © Rodrigues

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