General Information on the ECN Phyllis Classification

The ECN classification is an evolving scheme based on a mixture of plant physiology and practical considerations. Materials are divided into groups that are in turn divided into subgroups. In May 2003 several group names have been adapted and subgroups have been added or subdivided, mainly to reduce the number of "other" materials.

Explanation of the classification

Untreated wood

Wood is divided in two groups: untreated wood and treated wood. The untreated wood group contains fresh wood, park wood waste and wood from saw mills. Several individual tree species, such as willow, are separate subgroups. For other trees a division is made in tropical and other hardwood (trees with leaves) and softwood (trees with needles). If an overview of all hardwood data is needed one should select the subgroups beech, birch, oak, poplar, willow, tropical and other hard wood. Park wood waste is considered an untreated subgroup but in general information on the type of tree species is lacking. The subgroup others contains data records of unspecified untreated wood samples. Bark, cork, leaves and needles form separate subgroups.

Treated wood

The group treated wood contains composted wood (wood after being used in a composting process), demolition wood, preserved wood (treated with preservatives like CCA or creosote) and particle board. If a treated wood stream contains a mixture of the above mentioned types it can be found in the subgroup others.


From plant physiological point of view the difference between straw and grass is not always straightforward. Here the commonly used definition of straw (from grains like wheat, barley, rice and maize) is used. In May 2003, rape, rye, sorghum and sunflower have been moved from the subgroup others to separate subgroups. The subgroups others contains straw from other plants like oats and beans, straw mixtures and unspecified straw.


Different grass-like species can be found in separate subgroups of the group grass. Verge grass is a mixture of different (unidentified) grass species. The subgroup hemp has been moved from straw to grass and new subgroups have been created for jute and kenaf. These species are important sources of fibres. New subgroups fruit, vegetables and flowers/garden plants contain materials previously collected in others or in other organic residue.


In the group husks/shells one can find the outer parts of different nuts, like cacao-shells. The group name has been extended to include pits. This prevents ambiguity for waste materials from the olive industry. Previously, some of these materials were to be found in other organic residue, subgroup food industry.

Organic residues, manure, sludge

The group other organic residues now includes products. It contains a number of plant-based materials, such as new and waste paper, residues from agriculture and horticulture, residues and products from the food industry, the organic fraction from domestic waste and auction waste. Also textile waste is a subgroup in that group although in some cases it can contain fossil fuel based materials. Manure, also an organic residue, can be found as a separate group in the database. The group sludge is divided in sludge from sewage water treatment, sludge from the paper industry, waste water treatment, sludge from culverts and sludge from the food processing industry.


Municipal Solid Waste (MSW) and Refuse Derived Fuel (RDF) are clustered in one group, whereas the separated organic fraction from MSW (separately collected in the Netherlands) can be found in the group other organic residues.

Non-organic residues

The group non-organic residues contains waste streams which consist mainly of fossil fuel based materials, like electronic scrap, automobile shredder residues and cable waste. Although some forms of carpet waste consist mainly of natural materials it has been decided for reasons of clarity to place it in that group. In the subgroup plastics analysis data of individual plastics can be found, whereas the subgroups others contains information on mixtures and, for instance, car-tyres.


The group char contains the solid remains after pyrolysis of a great variety of materials in subgroups named after the main group of the original material.


The group algae with subgroup others contains aquatic fotosynthetic organisms that lack true leaves, stems, roots and vascular systems characteristic of plants.

Torrefied material

This group contains materials which have been given a thermal treatment at moderate temperature (around 200°C) to improve the fuel quality, e.g. grindability.

Fossil fuel

Data of fossil fuels, including peat, are added as a reference in a separate group.