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Sludge thickening by low energy microflotation technology

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Industrial Water Treatment
Municipal Water Treatment
Wastewater Recycling
Sludge Treatment / Disposal
Water treatment equipment and waste disposal systems
Water, sewerage, chemical and solid waste treatment plants


A German engineering company developed and patented a microflotation wastewater treatment technology that has proven very effective in sludge thickening. In most cases, activated sludge can be thickened from 3-5g/l to 50-70g/l without the addition of flocculants. It significantly reduces the sludge volume for disposal and makes it more suitable as biomass or for incineration. Applications are in municipal as well as industrial wastewater treatment. License agreements are offered.



Wastewater sludge is becoming increasingly difficult to dispose of. Due to new environmental regulations more restrictions apply for using municipal wastewater sludge as fertilizer in agriculture. For incineration purposes or use as biomass the sludge needs to be dewatered. If the sludge is to be disposed of, each percentage in volume reduction leads to savings.

The low energy microflotation wastewater treatment technology developed by a German engineering company has proven most effective in sludge thickening. The thickening of activated sludge can be realised energetically from 20Wh/m³ with microflotation. In most cases, activated sludge can be thickened from 3-5g/l to 50-70g/l without the addition of flocculants.

Microflotation is a further technological development of classical dissolved air flotation. Microflotation produces monodisperse distributed micro air bubbles of the size class 30-50µm to float the activated sludge in a stable way. More than 90% of the microbubbles are within this size range.

Besides air, all industrial gases can be used as microflotation gas.
The microbubble density enables high total solids (TS) concentrations in the separated sludge. At the same time, the system enables low total suspended solids (TSS) concentrations in the clear running of the plants.
The patented technology is furthermore equipped with a self-cleaning mechanism allowing maintenance-free operation.

Applications are not only in municipal waste water treatment but also in food industry, slaughterhouses, aquaculture, chemical industry, steel works and textile industry. Plants can be supplied with capacities ranging from 1m³/h up to 4.000m³/h.

In principle, each wastewater problem and sludge thickening task must be considered individually. Pilot tests can determine guaranteed operating costs and limit values. The company has containerised mobile technical plants that can be used for this purpose.

Partners are sought for license agreements. Potential partners are engineering or plant construction companies, who would like to integrate the technology in their wastewater treatment solutions. The license can be restricted to a region or market application, according to the partners interests.

Advantages & innovations

Cooperation plus value: 
The patented technology results in the following advantages: - Significant sludge volume reduction compared to other methods - Significantly lower energy requirements than conventional mechanical sludge thickening systems - None or little use of flocculation agents required - Not susceptible to fluctuation in hydraulic or material load - Clogging-free and maintenance-free operation - Low operational expenditure (OpEx) - Low capital expenditure (CapEx) - The process engineering is proven by large-scale references

Stage of development

Cooperation stage dev stage: 
Already on the market

Partner sought

Cooperation area: 
Collaboration Type License Agreement: The license can be restricted to a region or market application. Type of partner sought: Small or medium sized engineering office or intelligent plant construction company with process know-how and contacts to the relevant market. The partner could possibly (but must not) act as a general contractor. Role and tasks of partner The partner must have the appropriate infrastructure to enable international application of the technology. Individual countries or areas of application can be individually licensed. The partner will be trained by the German company and should then be able to offer advisory services. The partner should integrate the technology in wastewater treatment processes to optimise the sludge thickening and treatment. Activities in retrofitting and upgrading of existing or outdated plants should be of interest.