The drive for more sustainable production is a focus for many food and drink manufacturers. This is particularly true at Mars, a family-owned company, committed to becoming sustainable in a generation. A project looking at how to save water has delivered an added-value solution where both water and glucose can be recovered for re-use in an energy neutral process.
The potential reduction in water and glucose consumption is as high as 84% and is accompanied by reduced operational and wastewater discharge costs. It’s a more sustainable solution which makes a giant step towards improved productivity.
Methodology identifies interesting opportunity
Mars asked Royal HaskoningDHV to investigate water saving and re-use for a specific production process at its chocolate factory in the Netherlands, which is the largest in Europe.
The Water Scan methodology used by Royal HaskoningDHV involves a comprehensive assessment of water and mass balances and follows the production process itself. The benefits of such a methodology is that it can identify wider opportunities for sustainable solutions.
This was the case at Mars. It was clear an in-process option would deliver a reduction of up to 30% in the amount of water used. More interesting however was the water at the end of the process which contained particulates and glucose. If the particulates could be removed, could the water and glucose be separated and then re-used in the production process? If so, it presented the potential to recover more than 80% of the water.
Strengthening the business case
Many food and drink companies are interested in reducing their water usage and in water recycling. However, while there are real issues associated with water scarcity and waste, the fact remains that water is a comparatively low-cost resource. If a solution can be combined with extraction of a chemical or ingredient, the business case is improved considerably. Methods used to extract or separate these components from the water also need to be sustainable.
In the Mars case, a centrifuge was chosen as the best method to remove particulates as it needed no additional chemicals. To separate glucose and water, a membrane was not an option due to the potential for fouling. The alternative was evaporation, an energy-intensive process. To reduce the energy consumption of the evaporator, a mechanical vapour recompression was added. Looking at the heat balance across the production plant, it was clear that the energy input in the evaporator could be re-used in the production, creating an energy neutral evaporation process.
Testing and quality control
Product quality is fundamental to an A-brand company like Mars. Extensive testing needed to be undertaken for the proposed separation and re-use of water and glucose. Tests started in the lab and developed into a small scale and then larger scale pilots before being scaled up to an on-site pilot. This involved a 7-tonne evaporator being lifted by crane onto Mars production site in the Netherlands. Taste tests were also an important part of the process and concluded that the use of reclaimed water and glucose had no discernible impact on the product’s taste.
Partnership and long-term thinking is vital
While the project was carried out in the Netherlands, it relates to a production process that occurs at multiple sites. It means the solution can potentially be implemented across the world. Mars has another major chocolate factory in the United Kingdom, and there is particular interest at plants in water-scarce countries like Qatar, Mexico and China.
The route to the solution required trust, co-operation and commitment from both sides to deliver a more sustainable model for Mars food production. It helps Mars achieve its aims for sustainability and will also deliver a return on investment. This could be 2-3 years in a country like the Netherlands where the cost of wastewater disposal is high, or perhaps double that if measured purely on water and glucose recovery.