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WELTEC MULTIMix: size reduction, homogenisation and wet feeding

MULTIMix is a pretreatment system that links the intake of different feedstocks with a consistent liquid flow to the digester. It is particularly relevant where heterogeneous organic residues are processed alongside agricultural substrates.

4 min readSources are listed at the end of the article
Illustration of the WELTEC MULTIMix system for substrate preparation and wet feeding
MULTIMix integrates intake, size reduction and homogenisation before material enters a liquid process stream. The illustration shows the functional principle.

Different feedstocks rarely behave alike. Food residues, silage, manure and fibrous materials differ in moisture, particle size and tendency to form clumps. Feeding them straight into the digester increases mixer loading and makes steady feeding harder. MULTIMix is intended as an intermediate stage that prepares material before the main biological process.

What does MULTIMix do?

According to the manufacturer's public descriptions, the system reduces particle size, homogenises different inputs and feeds them as a liquid mixture. In organic-waste projects it can be linked to an intake tank, depackaging and pasteurisation. MULTIMix is therefore not always a standalone feeding machine, but a functional stage in a wider processing line.

Wet feeding allows prepared substrate to be transferred through a closed pipeline. This permits intake areas and digesters to be separated, while valves and pump controls distribute material among several tanks.

How it differs from a dry-feed bunker

A dry-feed bunker primarily receives and meters out solid material. Before discharge, MULTIMix changes its physical properties: it reduces and evens out particle size, adds a liquid phase and prepares a pumpable mixture. Comparing the two solely by intake tank volume would therefore be misleading.

For a wet system, consider the available recirculated liquid, dry matter content after mixing, energy use for size reduction and pumping, and wear on parts exposed to sand, metal or other foreign objects.

Where can the system offer an advantage?

MULTIMix is relevant when a plant uses a changing mix of feedstocks, needs to reduce the load on digester mixers or must integrate the feeding line with further waste treatment. WELTEC describes one project using it with an 80 m³ feeding tank, where food residues are reduced in size and homogenised before further processing.

A simple plant using one consistent, free-flowing feedstock may not need this degree of pretreatment. The investment needs to be justified by steadier operation, greater feedstock flexibility or fewer problems in subsequent process stages.

What to request in a quotation

The quotation should specify permitted feedstocks, the maximum size and type of foreign objects, expected flow for the actual mixture, required liquid volume, drive power, wear parts and cleaning method. Automation, safety interlocks and what happens if a downstream pump or valve stops are equally important.

Practical notePretreatment is only as effective as its integration with upstream intake and downstream pumps, pipelines and digester. Looking at one piece of equipment in isolation often gives a misleading picture of capacity.

Sources and further reading

This description is based on publicly available manufacturer information. The exact configuration, capacity and equipment scope depend on the project and must be confirmed in a technical quotation. It is for information and does not replace process calculations.