Physico-chemical water treatment

Challenges

In numerous production processes water is used as a solvent or means of conveyance, as cooling water or washing water. Increasing costs for the purification and disposal of wastewater, regional or seasonal shortage of water, and a growing awareness of environmental issues within companies have increased water recycling. Water is used several times and impurities have to be removed selectively. In many cases the currently established processes and systems cannot do the job without adaptation and support from new, selective systems.

Our solutions

The use of oxidative and electrolytic processes for water treatment is one of the main fields of research of Fraunhofer IGB. We work on the improvement of existing processes such as adsorption, filtration, flocculation/precipitation, electrodialysis, homogenization and disinfection as well as on new approaches in process and unit operations. Together with industrial partners, new concepts and technologies are being developed at Fraunhofer IGB also to industrial scale. Water treatment and the circulation of process water can thus be carried out economically and sustainably.

Advantages

With oxidative and electrolytic processes, it is possible to oxidize dissolved contaminants or pollutants that are difficult to break down. In general, electrolytic and oxidative processes have the following advantages:

  • Complete mineralization of pollutants possible
  • Staff savings and increased reliability
  • No increase in salinity, which enables recirculation
  • No disinfection by-products – in particular no halogenated compounds
  • Less handling of hazardous chemical agents
  • Little or no sludge formed
  • Hygienic outflow water
  • Robust process – discharge criteria can be met reliably
  • Available quickly – standby operation possible
  • Suitable for varying quantities and qualities of wastewater

Applications

At present the focus is on industry-oriented studies of landfill leachate and textile effluents. The aim here is to meet the discharge criteria of the communal treatment plants in a cost-effective way. In other projects we have developed new technical solutions for UV treatment and anodic oxidation together with our industrial partners. These projects aim to make the solutions ready for market launch.

Technologies

Electrophysical precipitation

Advanced Oxidation Processes (AOP)

Photolysis

Electro-oxidation and -reduction

Systems

Process development

In cooperation with industrial partners, new concepts and technologies for the sustainable treatment and purification of process water for a very wide range of applications are being developed and optimized at Fraunhofer IGB up to industrial scale. Water treatment and the circulation of process water can thus be carried out economically and sustainably.

Process optimization

In many cases the currently established water treatment processes and systems cannot do the job without adaptation and support from new, selective systems. Fraunhofer IGB is therefore working on the further development of existing processes such as adsorption, filtration, flocculation/precipitation, electrodialysis and disinfection as well as on new approaches to processes and components.

System integration

Especially in the case of typical industrial wastewaters with a complex composition, efficient separation of substances is frequently not possible with just one single process stage. By combining and integrating various processes we are able to develop efficient and coordinated solutions, which are optimized in their overall impact as a process chain regarding selectivity and energy efficiency. In this way, results can be achieved that exceed the sum of the results of the individual process stages.

Combination and integration of oxidative and electrolytic processes

Oxidative and adsorptive processes such as electrophysical precipitation can be combined, depending on the problems to be solved. By doing this, results can be achieved that exceed the sum of the results of the individual processes.

A further advantage of these processes is that they are suited to standby operation and can be switched on or off at any time. Integration into existing plants and automation including autonomous operation or remote control are feasible without any problems. Continuous online logging of organic carbon (TOC, total organic carbon) can be effected, enabling requirement- based and thus energy-optimized treatment.

Lubricants for wet machining of fiber reinforced plastics

Dust generated during milling of fibre reinforced plastic.
© Fraunhofer IGB
Dust generated during milling of fibre reinforced plastic.

Fiber‑reinforced plastics (FRP) are lightweight and have excellent stiffness, which is why they are increasingly used in the automotive and aerospace industries. The final processing steps e.g. milling and grinding produce dusts of hard glass or carbon fibers. The aim of the project is to use cooling liquids as lubricants to reduce tool wear and at the same time improve occupational safety and machine safety.

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