MID MIX technique

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.

Carbonating
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.

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.

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.