In short MID MIX is an innovative technique in which sludge waste is processed into a reusable raw material.It has the designation "best available technology". Re-usable raw material is created through the development of techniques and the addition of quicklime to sludge waste.


According to the international standards, waste is any substance or object, defined by waste categories, which the holder discards or intends or is required to discard. Waste types are classified into groups according to their characteristics and place of origin.
According to the laws and regulations waste treatment is a procedure in which the mechanical, physical,thermal, chemical or biological processes, including sorting, changing characteristics of the waste in order to reduce the quantity and / or characteristic of hazardous properties with easier handling.
Likewise, laws and regulations are defined for recycling of waste, and  the definition of the  procedure in order to use the waste as useful material or for energy purposes.

Many types of municipal and industrial waste materials are on the basis of hydrocarbons, which in addition tothe structure of CH still contains other compounds and elements (Cl, P, S, N, heavy metals, etc.). These elements are treated as non-hazardous or hazardous waste. Types of waste are the following: organic and inorganic materials, hydrocarbons, municipal and industrial sludge, emulsions, solvents and mixed waste materials are successfully from the liquid or pastes shape, transformed into solid state, powder shape, by technology using calcium-based reactant.
In the case of sludge from waste water treatment plants, with no significant amounts of hazardous materials,such sludge must be processed / recovered to be able to dispose or reuse as raw material. 

Technology MID-MIX ® is recycling of waste material based on hydrocarbons, where the result is a dry white powder that can be used as a raw material. In describing of the technology we will define the characteristics of the product which is called NEUTRAL.
Patented MID-MIX ® process for the recovery of municipal sludge and other various hazardous industrialwaste, is the result of years of testing and different kind of transformation of hazardous waste in an inert form, with the specific processing technology based on calcium reactants.

Solidification is the process that is used in a wide range of ecological processes that changes the physical and chemical properties of materials with the goal of becoming the physically-chemically suitable for further use.

Solidification in particular has been used successfully for treatment of liquid waste and sludge hydrocarbon-containing organic compounds, heavy metals and various facilities which have industrial hazardous wastes. The objective is that the waste solidification changing material original physical-chemical form in which the hazardous content is immobilized, so after stabilization hazardous content is not excreted in the natural environment.


MID-MIX ® physical-chemical technology of solidification process, characterized by:

- Mutual intensive contact of waste and process additives,
- Exothermic reaction in the reactor with the evaporation of water,
- Vacuum gas and molecular encapsulation  of particles in a complex calcium grids,
- Hardening-solidification of the entire contents in the reactor.


The final effect of the technological process is:

- Decrease (reduction) of the initial waste amount and
- Neutral achievement that is inert and has a diverse application value.


Simply, MID-MIX ® technology is a physical-chemical process that “transforms” waste matter "translates" into a material that is adapted to the environment, because when in this new condition the matter imposes no threat to the environment. Such processing technology has always achieved a result that confirms the removal of all or most harmful characteristics defined by MDK standards.


This technological process handles different types of waste hydrocarbons, various organic industrial types ofwaste and other waste from the treatment of municipal wastewater. The technological process can alsoprocess various inorganic waste materials, such as ash, contaminated soil and liquids from galvanic and or any other industry.


Types of hazardous and non-hazardous wastes that are suitable for processing in the MID-MIX ®technology are:

- Used oil, motor oil and oil emulsions;
- Refinery and petrochemical waste;
- Oily contaminated soil and sludge;
- Waste from the pharmaceutical industry;
- Tar, varnish, paint, paraffin residues;
- Residues from separator filters;
- Galvanic sludge, emulsions, and thinners;
- Various organic wastes; fats and oils
- Sewage sludge from municipal and industrial wastewater treatment,
- Industrial lubricants, scrap grinding, iron shavings and wool powders
- Waste products contaminated with pesticides
- Asbestos dust and sludge



Neutral, obtained by MID-MIX ® recycling process has characteristic physical and chemical properties that differ significantly from other types of materials and especially because of the low density (c = 835-975 kg/m3), hydrophobicity (water resistance coefficient: k = 1x10 -9 m/s), fire and flammability (flash point: Tk> 350C)

Neutral as the product MID-MIX ® technology with its characteristics can be used in many useful ways. Herewe will show some of the possibilities of neutral application, which does not include the fact that there are other possibilities.

Neutral as the product MID-MIX ® technology with its characteristics can be used in many useful ways. Here we will show some of the possibilities of neutral application, which does not include the fact that there are other possibilities.


Neutral as a supplement (filler in concrete and asphalt)

Neutral can be mixed with cement in a special technical way (because it does not link with water, itfloats on it and it does not dissolve), so you can acquire concrete products that have a lower specific gravity,higher hydrophobicity and increased thermal and acoustic insulation.

One of the ways of using Neutral is formation of concrete blocks and concrete products of different shapes that have different formats and methods of application. Whereas all  have the same ecological, physical-chemical and mechanical properties of the appropriate standards that apply for a variety of conditionscommon in construction (laying of garden trails, parking lots lining, making pet fence, production of decorativesculpture, covering roofs, etc.).

Because of the capsulated particles of the base material, there is an increased percentage of pores in the composition of the material and specially designed element surface with holes of various irregular shapes and dimensions an extremely good acoustic-insulating properties are achieved. Such elements are ideal as a noise barrier along the roads and highways and around industrial plants.


Neutral as the primary raw material in the cement industry.

In 2008. tests were performed in Spain by Eduardo Torroja Construction Laboratory Science Institute(CSIC, Superior Council of Scientific Investigations), Ciments Molins, HERA Alquimia and AUMA. The test demonstrated the theoretical feasibility and convenience of using Neutral as partial replacement of limestone in cement manufacturing.

The usage tests of Neutral in industrial conditions was carried out during the first half of 2010. Neutral was used as a substitute for limestone. Observations were made on characteristics of the cement in the form ofquality, product characteristics and emissions of CO2.

On the basis of results it can be concluded that the quality of the output is not affected by adding cement to neutralize in the amount of 5%. Percentage of Neutral was limited with the available amount of Neutral, so that higher percentages were not questioned. It also showed that emissions were not increased and was in accordance with all regulations.

Astra International Engineering Ltd.
Vinogradska 43, Zagreb, Croatia

Domobranska 21, Zagreb, Croatia
+385 1 387 2202
+385 1 387 2142

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