The production of beer and spirits requires large volumes of water and while improvements have been made, there is still more that can be done to reduce the water footprint of brewing and distilling. In particular, the characteristics of industrial wastewater, produced by the production process, provide the opportunity for companies to optimise the use of resources through the production of biogas via Anaerobic Digestion (AD).
Brewing and distilling are water intensive processes. The Beverage Industry Environmental Roundtable (BIER) reports that the average water use ratio (WUR) of beer is currently around 3.35 litres of water per litre of beer. The WUR of spirits is approximately 32.7 to 1 and even when the water used for cooling is excluded the ratio is still 10.9 litres of water per litre of spirits produced. This is an issue that is gaining increased attention and companies are starting to take action, with the latest figures from the Scotch Whisky Association (SWA) reporting that water efficiency among its members has improved by 29% since 2012.
Much of the water used in the production process ends up as wastewater and is typically discharged to the sewer or river following treatment. However, a large proportion of this wastewater is actually suitable for recovery, treatment and reuse for applications such as boiler feed water, cooling processes and certain cleaning activities. As the cost of discharging the water can be twice as much as the cost of mains supply water, there is a significant financial incentive to investing in processes that will reduce the volume of industrial wastewater.
In addition to the environmental impact and financial implications of reducing the water requirements of the plant, there is also an operational benefit for the brewery or distillery. With UK weather becoming more extreme and unpredictable, relative drought conditions are increasingly common, putting pressure on supply. Recent years have seen whisky producers reducing or even halting production due to a lack of water. Therefore, reducing the amount of fresh water required in the production process will mean that when water supplies drop, the available water can be used to continue production.
Furthermore, the right approach to wastewater treatment can also reduce the energy costs and carbon footprint of the production facility. The high chemical oxygen demand (COD) of the wastewater, caused by the presence of sugars, ethanol and soluble starch, makes it ideal for biogas production by AD. This can be used in an on-site combined heat and power (CHP) plant to provide energy and heat for the facility, reducing reliance on non-renewable resources and lowering energy bills. In some cases, distilleries and breweries are able to produce an excess of biogas and electricity, which can be sold back to the grid.
Case study: Diageo Cameronbridge Distillery
The Cameronbridge distillery is Diageo's largest grain whisky distillery in Scotland, producing about 105 million litres of spirits at the site each year. Currently 20% of Scotland's wheat harvest is processed through Cameronbridge.
Diageo wanted to create a flagship manufacturing site that would demonstrate best practice in sustainability and renewable energy. The global beverage company worked with Veolia Water Technologies UK and Veolia UK to create a wastewater treatment and green energy solution. The bio-energy plant generates renewable energy from the spent wash and clean in place (CIP) liquors produced during distillation. The wheat, malted barley and yeast is separated from the wash and dewatered to provide fuel for a biomass boiler.
The remaining liquid is then treated in a purpose built wastewater treatment plant. The first stage of treatment is an anaerobic process, generating biogas to provide additional fuel for the biomass boiler that provides heat and energy to the distillery - providing 98% of the steam and 80% of electrical power used at the distillery and reducing annual CO2 emissions by approximately 56,000 tonnes. The additional wastewater is then treated using a membrane bio reactor (MBR) and reverse osmosis (RO) system to produce high quality water for CIP and boiler feed water.
There are a range of wastewater treatment technologies available to help distilleries and breweries extract the greatest value from their wastewater resources. The wastewater solution that best meets the needs of the specific site will depend on a number of factors.
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About the Author
Daniel spent the first 10 years of his career managing proposals for large EPC (Engineering Procurement & Construction) power projects. Daniel has been with Veolia Water Technologies for 7 years where he has managed the proposals for Industrial and Municipal projects. Daniel also now manages the sales team for Industrial Wastewater opportunities ensuring that Veolia Water Technologies work with each customer to design and deliver the most appropriate solution for their needs.