Since the introduction of its ‘Together Towards ZERO’ sustainability programme in 2017, the Carlsberg Group has set its sights on zero carbon emissions and zero water waste at its breweries. The ultimate goal is to reduce from 340 litres of water per 100 litres of beer (the 2015 baseline), to 170 litres of water per 100 litres of beer by 2030.
To assist in this ambitious evolution, Carlsberg’s Fredericia brewery in Denmark has been selected as a test site for the company’s first total water recycling plant, which will be fully operational by spring 2021. The new installation will recycle 90% of all process water to reduce average consumption at the site. This feat will make Fredericia the first brewery to virtually eliminate water waste, and one of the most water-efficient large breweries in the world. It is estimated that the total water recycling plant will also reduce the brewery’s energy consumption by 10% through its own biogas production and the recirculation of hot water.
The water recycling plant focuses solely on process water used by Fredericia for the sanitation and cleaning of equipment and bottles - not for water in brewing. Waste process water was previously sent to the drain as it contains constituents such as detergent, bacteria, salts and a relatively high concentration of soluble organics like sugars. However, the new water treatment and recovery plant enables the brewery to reuse 90% of this water in its sanitation and cleaning processes.
A 90-minute drive west of Copenhagen, the Fredericia brewery was inaugurated in September 1979. Comprising a brewery, bottling plant and warehouse terminal, the site employs more than 600 people across a host of business functions.
The state-of-the-art water recycling plant currently being installed at Fredericia is the result of a progressive public-private partnership named DRIP (the Danish partnership for resource and water-efficient industrial food production). DRIP comprises not only technology providers and universities, but the Danish environmental, food and veterinary authorities. Engineering consultancy NIRAS is both leading the project at Fredericia and providing the construction services. Its engagement began with a feasibility study from an economic and stakeholder perspective, explains Søren Nøhr Bak, expertise director at NIRAS. “One of the main challenges of this project is to achieve good assessment and control of stakeholder engagement.”
When the brewery became operational in 1979, the industry norm was to operate on 700-1,000 litres of water per 100 litres of beer, but Fredericia managed to function on 400. In the years since, following the introduction of further efficiencies, this quantity has reduced to 290 litres. The achievement is particularly impressive when considering the complexity of the site, which brews more than 200 different products for the Carlsberg portfolio.
“Our assessments of Fredericia led to the acknowledgement that this could be a prime, ground-breaking project for the worldwide brewing industry, which would bring about further significant water usage reductions in a viable and safe way,” says Nøhr Bak.
As a point of note, the recovered water is pure enough to be considered of drinking quality. The reason for this level of purification is that it allows the new recycling plant to make use of existing water infrastructure. Costs for a dedicated pipework system would have to be met if the water was not of the same quality as its mains-supplied counterpart. According to Nøhr Bak, ensuring the recycled water is of drinking quality is also important from a psychological perspective. Somehow it feels better to be using purified recovered water, even for cleaning and sanitising. The quality of the recycled water means it is also supplied to the brewery’s employee shower facilities.
Carlsberg’s total water recycling plant at Fredericia represents a new innovative approach to the safe reuse of rinsed process water, and the project leverages a number of innovative technologies to improve water efficiency.
HOW IT WORKS
To provide an overview of the plant’s function, the system has been designed to first evaluate inflows and concentrations, after which screens are deployed to remove coarse material from the used process water.
“The first really interesting step is that we then use an anaerobic reaction process, where bacteria are capable of converting the soluble organics into methane, and that methane into biogas,” explains Nøhr Bak. “The biogas produced constitutes approximately four times as much energy as that consumed by the processes that follow. As a result, the plant is more than energy-neutral – in fact we have a surplus. Additionally, the recovered water returns to the brewery warmer than it set out.”
Whereas mains cold water is supplied to the brewery at 8°C, the water recycled by the new plant is returned at 25°C. Subsequently, far less heating of the process water is required for cleaning the equipment and bottles, which in turn makes it possible to reduce energy consumption across the entire site by 9-10%.
Following the anaerobic reaction process, a biological polishing step is deployed whereby another bacteria type removes any remaining organics, as well as nitrogen and phosphorus. Ultrafiltration (UF) membranes then serve as part of an installed membrane biological reactor process before a reverse osmosis (RO) membrane plant yields 90% recycled water. The remaining 10%, which has a concentrated brine content, is discharged into a municipal sewer to a saltwater recipient.
Once the RO is complete, an advanced oxidation process removes any small organics that pass through the membranes. A remineralisation filter subsequently adds a degree of hardness back to the system, thus avoiding corrosion in the brewery’s pipework. Chlorine dioxide is added as a final step to maintain disinfection potential.
Arjun Bhowmik, VP production - western Europe, Carlsberg Group, adds: “The new water recycling technology means that Fredericia can become an important learning platform for all of our facilities.”
Until final commissioning is complete next year, NIRAS will continue to execute the project, with all the daily challenges this brings. A topping-out ceremony for the construction part of the project was held recently and attended by Denmark’s Minister of higher education and science, Ane Halsboe-Jørgensen (pictured, right).
Among the academic stakeholders within DRIP is the Technical University of Denmark (DTU), where Lisbeth Truelstrup Hansen is a professor of microbial food safety and environmental hygiene.
She states: “DRIP comprises industry partners that have got together with universities and government agencies to solve challenges in the sustainable reuse of water. Partnerships are extremely important because they immediately bring everyone to the table. For Carlsberg, they’ve been able to sit down with suppliers who can provide the optimum equipment to help reach the required technological solutions. In addition, government agencies have been guiding us through the regulatory framework that we have to abide by.”
WATER, WATER EVERYWHERE...
Water is clearly essential to Carlsberg, both for its products and its processes. The company’s aim is to eliminate wastewater, which means maximising efficiency, and treating and reusing water wherever possible. In 2019, Carlsberg achieved a 12% reduction in water consumption (from 2015). Building on this progress requires further investment, innovation and working in partnership, hence the decision for a more concentrated focus on water recycling.
Of course, there is also a huge environmental factor at play here. In a changing climate, it is predicted that drought will become more widespread, reducing the quality and availability of water. Such an eventuality is the principal reason why the company is investing in the technology, not simply to maximise efficiency in its breweries, but to increase the availability of fresh water for the local communities whose resources it shares.
Having recently celebrated the 40th anniversary of its Fredericia brewery, the installation of the new water recycling plant is helping Carlsberg take a big step into the future.