MID MIX technique

VSGM wants to contribute to a circular, environmentally friendly society. We do this with our MID MIX solution. The installation consists of several components. From the supply buffer, dewatered sludge is pretreated and then processed in two reactors. Here, CaO is added. By exothermic reaction, moisture is extracted and various chemical and physical processes take place. The core processes taking place in the plant are soldification and molecular encapsulation of heavy metals and other contaminants such as PFOS/PFOA, PAHs and PCBs. The water – about 35% – from the sludge passes through a cloth filter along with the ventilation air and leaves the stack clean washed in a scrubber. About 65% of the total input mass is converted into the final product Neutral. No residual product remains during the process to be disposed of as waste.

End Product Neutral

After processing sludge in MID MIX, the circular building material Neutral is created. It consists of 80%-90% Calcium hydroxide (Ca(OH)2 ) and 20%-10% Calcium carbonate (CaCO3 ). Neutral can be used as an aggregate in construction, as a soil improver and as a substitute for primary building materials including cement and primary Calcium hydroxide. This makes the technique interesting because there is always a very beneficial impact on the environmental score of the MID MIX process.

In an additional process for Neutral, called carbonation, Neutral is reacted with CO2 which results in permanent storage. In 1,000 kg of Neutral, between 500 kg and 700 kg of CO₂ can be permanently sequestered (CCU/CCS). This CO₂ can be captured elsewhere and directed to a ‘CO₂ conversion box’. When placed next to a flue gas duct, the CO₂ can be routed directly to the box in which the process takes place. In both cases, a hybrid, synthetic limestone flour is the final product. Carmeuse has issued an off-take guarantee at a positive value for this circular product.

Choice of route to a final product

Each company has its own motives for choosing MID MIX. It may be from a financial perspective, or perhaps the environmental perspective is central. We can engineer MID MIX installations for your organization in such a way that we can work towards one type of end product, from the existing process. This allows us to easily adapt an initiated route to the new objectives in case of changing market conditions or changing legislation. After all, nothing is more subject to change than environmental legislation and its associated consequences. Investments in MID MIX technology are therefore not “cast in stone” and can be set up flexibly in the long term. We would be happy to discuss this with you in order to determine the most suitable route for your organization. Make an appointment soon!

Environmental impact

By using natural chemical reactions in the processing unit, MID MIX is a system that consumes little energy. It has a very low CO₂ footprint and emits no NOx. The route MID MIX + carbonation (capturing CO₂) has a lower environmental impact and thus a better score than sludge incineration. The route using Neutral (80-90% Calcium hydroxide) as an alternative secondary feedstock also scores above average. In both cases there is even a negative environmental impact! This makes all routes environmentally superior to sludge incineration. Although the use of CaO in MID MIX creates environmental impacts, these are more than offset by the uptake of CO₂ from the sludge and the circular application of the Neutral.


MID MIX technology was developed almost 13 years ago in Croatia. Since then, the technology has been further developed. More than 130 types of sludge and waste have now been successfully processed with the MID MIX technology, which has been patented worldwide. VSGM markets MID MIX in large parts of Europe.

Application and capacity

The basic MID MIX plant with a single line processes between 8 and 10 tons of sludge per hour. However, various configurations are possible that can significantly increase the processing capacity at a site by deploying multiple lines in parallel. Given the limited footprint of the plants, they can often be placed at sites where sludge is collected. We can also flexibly deploy a semi-relocatable plant at sites where sludge is generated. The system is steerable to a required output. Do you have larger volumes? Then we design custom installations. Would you like to see how our installation works? Make an appointment to come and have a look at our trial/demo installation in Meppel.


​Would you like to know if MID MIX is suitable for your company? We are happy to advise you without obligation.

Wanraaij 4
6673 DN Andelst

+31 6 53 254 205

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