Scientific research

Capture CO2 (carbonation)

CE Delft has conducted an mLCA involving the route of storing CO2 in Neutral (the final product from MID MIX) and comparing it with burning sludge. A quote from this study speaks for itself. “The MID MIX + carbonation route is environmentally higher value than sludge incineration. The other routes are environmentally lower value than sludge incineration. When the entire electricity use of the MID MIX + dehydrating route is met with self-generated renewable electricity, this route becomes equivalent to sludge incineration.”

In this context, together with our supplier of quicklime – Carmeuse – we developed the CO₂ box in which the carbonization process takes place. In addition, Carmeuse facilitates the inclusion in the so-called ETS/CCU/CRC system. This allocates the value of storing CO₂ to the user of a MID MIX plant. In addition to a major environmental impact, this also has a major positive impact on the financial picture of sludge treatment with MID MIX.

Below is a schematic representation of the climate impact when processing 1 ton of water treatment sludge. In this comparison, the burning of sludge has been calculated as being the production of green electricity with green biomass. CO₂ emissions are therefore not calculated.

  • Sludge incineration scores 67 points in environmental impact.
  • MID MIX with the route of dehydrating Neutral scores 14 points in environmental impact.
  • MID MIX with the route of Carbonating Neutral scores -/- 123 points in environmental impact.

Other applications Neutral

Cement replacement

Neutral can also be used in a blend for soil stabilization. Field research has shown that in this blend Neutral can replace 50% of the normal amount of cement without a significant reduction in compressive strength. Since cement has quite a heavy CO2 footprint, the environmental benefit is clear. In terms of cost savings, this application also makes a lot of sense.

Flue gas cleaning

The application of Neutral as calcium hydroxide was investigated by engineering firm TAUW and elaborated in an LCA. Also in this study, MID MIX was compared with sludge incineration. The study included a table of the Environmental Cost Index (EQI) of both processes. This table indicates an MKI value for incineration of several tens of euros. However, the MID MIX process scores tens of euros negative, in this case favorable for the environment. Throughout Europe, flue gases from energy and incineration plants are cleaned with calcium hydroxide. This is one of the possible routes for a very sensible application of this secondary raw material without any environmental impact.

One route investigated by SGS-Intron is the use of Neutral in concrete products and asphalt. Certification EN-12620 has since been issued for this route. The environmental impact was not investigated further in this study. But the certificate does allow Neutral to be used in this way.

CE product certification

A clear path has been laid out by SGS-Intron for the MID MIX user to go through for product certification either as an active (Type II) filler or as an inert (Type I) filler. This EAD/ETA procedure is available upon request.
It is very real and logical to draw the conclusion that processing of other sludges (industrial sludges) that are landfilled or burned in a waste incinerator will have a significantly worse environmental score than processing with MID MIX technology. Want to know more? Then click here for CE Delft’s full mLCA. TAUW’s LCA is available upon request. Please feel free to contact us and we will provide you with further information.

Do you want to know more? Request more information using the contact form.


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

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