Water and waste water technology

Waste water

Efficient solutions for the treatment of contaminated water, free from chemicals or microbiological agents – from consulting to plant design. With the right combination of process steps, even constituents that are difficult to treat can be broken down in a targeted and economical way in centralized and decentralized plants.

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Test setup for photocatalytic oxidation.

Disinfection

 

The disinfection of pre-cleaned waste water is of great importance when it comes to improving the hygienic quality of water bodies and utilization as service or irrigation water. Many conventional process types use chemicals, which need to be stocked accordingly and the use of which often requires compliance with strict safety standards. Therefore, Fraunhofer IKTS has developed solutions that can be easily integrated into processes and work without chemicals. For instance, Fraunhofer IKTS has a pilot manufacturing plant for ceramic membranes to be used for sterile filtration and made from titanium dioxide, silicon carbide and aluminum oxide.

Furthermore, photocatalytic electrochemical processes for the complete removal of pathogenic microorganisms through oxidation processes based on radicals (AOP: Advanced Oxidation Processes) are being developed. In accordance with the specific requirements, these processes can be used readily and efficiently in various operating modes.

Advantages:

  • Safe disinfection
  • Cost-efficient and durable materials
  • Versatile use according to specific needs
  • Energy efficiency operation
  • No consumables required
© Fraunhofer IKTS
Functionalized cellular ceramics for waste water treatment.

Breakdown of anthropogenic trace substances

 

The contamination of water bodies with organic substances of anthropogenic origin – pharmaceutical trace substances in particular – is a growing concern. Effective and efficient elimination is possible with adsorptive, as well as oxidative, processes and process combinations. For the selective removal of pollutants, Fraunhofer IKTS has developed an integrated process combination of activated carbon adsorption and membrane filtration (MF/UF). This combination has already been tested successfully for the elimination of various trace substances, such as Carbamazepine and Diclofenac.

AOP processes, such as photocatalytic or electrochemical treatment processes, are suitable for the complete breakdown of persistent contaminants. To achieve this, Fraunhofer IKTS has developed TiO2-coated cellular ceramics which require lower energy input compared with other AOP procedures, thanks to their large interaction areas and better penetration depth of light irradiation.

Advantages:

  • Complete breakdown or selective separation of organic compounds
  • Versatile use according to specific needs
  • No consumables required
  • Regenerable materials
  • Simultaneous disinfection possible
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Pilot plant fpr the separation of sulfates.

Treatment of mining water

Sulfuric acid and mining water that is sulfate rich and contains heavy metals wreak havoc on water bodies worldwide. Aside from the RODOSAN® process, there are hardly any alternatives at all when it comes to the possible treatment of such water, especially in terms of separating sulfates (sulfuric acid). The RODOSAN® process involves membrane electrolysis and enables a largely selective separation of sulfate. At the same time, heavy metals (Fe, Mn) and aluminum are eliminated quantitatively and buffer capacity is generated in situ by electrochemical means. The separated sulfate can then be converted into reusable material, such as fertilizer.

The process has been pilot tested for various use cases on the level of industrial electrolytic cells and configured in a modular way, which makes it possible to treat smaller water volumes, as well as larger ones. A pilot plant with a capacity of 6 m3/h (roughly 1,600 US gallons per hour) is available for technical analysis and for optimizing the procedure.

Advantages

  • Sulfate separation 45–70 %, partial demineralization
  • Quantitative separation of aluminum, iron, manganese
  • Generating buffer capacity
  • Production of fertilizer as a co-product
  • Wide range of applications (hydrochemistry, flow rate)
  • Production of hydrogen and utilization of CO2
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Flocculated organic suspension.

Flocculation and dewatering

 

Potable water and waste water treatment plants use so-called flocculants to eliminate undesirable substances, reduce the water content and thus closely control the properties of sludge. The remaining water content often contributes significantly to the costs when utilizing the sludge produced. This means the more efficient flocculation and dewatering are, the more economical utilization or disposal becomes.

In the future, the introduction of new legislation will regulate more closely the use of conventional synthetic flocculants in the field of potable and waste water treatment, possibly to the extent of prohibiting it completely. Therefore, Fraunhofer IKTS is focusing on developing, testing and implementing, within the process, cost-efficient and highly effective flocculants based on renewable raw materials – in addition to optimizing conventional flocculation and dewatering processes by means of measuring technology.

Advantages:

  • Use of sustainable and non-toxic raw materials
  • Materials that equal or outperform conventional flocculants
  • Legal compliance possible when used in potable and waste water treatment
© Fraunhofer IKTS
Analytical system for pollutants and trace substances in the water.

Environmental sensors

 

Detecting pollutants and trace substances in water and waste water is indispensable for the control of environmental and water engineering equipment, in particular with regard to the use of energy and chemicals. However, the intervals typically applied for sampling and chemical analyses are often too long to allow for efficient control.

Fraunhofer IKTS is dedicated to the development of rugged molecule and contaminant sensors for applications in the field. On account of their reduced sensitivity, these substance-specific sensors should not be seen as competing with analyses in the lab, but rather as reliable on-site rapid-alert systems, integrated into the specific plant, in case of elevated local contaminant concentrations. They can focus on a variety of molecular types, depending on the plant's requirements.

Advantages:

  • Plant-integrated analytics with short sampling intervals in the region of a few minutes
  • High ruggedness and failure safety
  • Chemicals used offer good shelf life and are very easy to handle
  • Versatile detection of various molecular types