Seepage of retentate water reduces wastewater

According to the principle of “avoiding mixing”, Mifa AG is reducing the volume of wastewater by separating industrial wastewater from so-called retentate.

  • The reverse osmosis plant (the photo shows the control panel) removes substances such as salts from water. This produces the purified water for Production (osmosis water, permeate) and the remaining water in which the salts are concentrated (permeate).

  • Patrick Bechtel, head of Operating Technology, and Hans Peter Dietrich, head of Infrastructure, maintaining the reverse osmosis plant units.

  • Development of production volumes in proportion to water consumption and waste water volume since 2003. Whilst production has increased by more than one third in the interim, waste water volumes have been reduced by 28% (both figures relate to the production weight).

Water is needed to produce detergent and cleaning agents. Some of this water goes into the finished products, such as liquid cleaners. However, what happens to the rest of the water?

Water’s route into production starts with the drinking water that flows into the Mifa factory through the company’s own supply lines. However, the water has to be carefully prepared to meet production’s high quality standards. First, the water is softened during pre-treatment in the ion exchanger. The ecological advantage of this process is that softening does not involve the use of any chemicals containing phosphate that would impact the environment. The water then enters a special reverse-osmosis plant, where some components, such as salts, are removed from the drinking water. This creates two types of water: first, the prepared “pure water, osmosis water” (permeate) that can now be used for production. Second, about a quarter of the drinking water becomes so-called concentrate or retentate. It is not wastewater, it is clean. It differs from pure water in that it contains the substances that have been removed from the pure water, for example, it has a higher concentration of salt, which means it cannot be used further. However, it does not make sense to mix the retentate with industrial wastewater from production.

“Mifa AG adheres to the principle of ‘avoiding mixing’”, explains René Gerber, Head of Operations & SCM. This means that the retentate is conducted separately from the industrial wastewater to a special area on the company premises. There, it seeps into the ground and returns to the natural water cycle. The benefits are obvious: the amount of wastewater is reduced and this takes the strain off the wastewater treatment plants and reduces costs.

The seepage of the retentate is just one example of the deliberate and efficient use of the valuable resource water at the Frenkendorf site. Increasing the awareness of all employees is also important to Mr. Gerber: “Just one dripping tap wastes about 15 litres of water per day, so it’s also important to carry out minor repairs quickly. To get everyone on board, we are organising a day of action dedicated to water in the autumn. Employees will, for example, be able to purchase water-saving sets for their homes at a reduced price; these sets will save up to 50% water.”

So lots of small measures together lead to measurable savings that are to be further consolidated in the next few years. Gerber explains: “With increasing production volumes, our freshwater consumption also increases because many of our products contain water. However, since 2003, we have been able to keep the amount of wastewater roughly constant, despite higher hygiene requirements and the fact that, in terms of weight, our production volume has increased by more than 35% since then.”

Sustainability facts on the efficient use of water at Mifa AG:

  • Industrial wastewater is not mixed with the retentate: after pre-treatment, industrial wastewater flows into the wastewater treatment plant and the retentate seeps into the ground in a special area of the company premises.
    - 2014 amount of infiltration instead of via treatment plant: 3727 m³ (only 4 months)
    - 2015 amount of infiltration instead of via treatment plant: 9440 m³ (12 months)
  • Mifa AG holds a regular day of action dedicated to saving water and efficient water management for its employees.
  • Since 2003, Mifa AG has kept the volume of wastewater roughly constant, despite the fact that hygiene requirements have increased since then and the production volume (weight) has increased by more than 35%.
  • The current climate and energy strategy of Mifa AG for the period 2012-2020 stipulates that specific water consumption must be reduced by at least 1% per year.

Resource efficiency

Water & Soil

World of Employment

Production & trade