Please note that the names in bold are country representatives
| Organisation | Country |
| KBVÖ Kompost & Biogas Verband Österreich www.kompost-biogas.info | Austria |
| Ingenieurbüro Wellacher e.U. www.ibwellacher.at | Austria |
| VLACO - Flemish Compost Organisation www.vlaco.be | Belgium |
| Croatian Compost Plant Association www.kompost.hr | Croatia |
| Premier Shukuroglou Cyprus LtD www.premier.com/cy | Cyprus |
| CZ Biom www.czbiom.cz | Czech Republic |
| ZERA - Zemědělská a ekologická regionální agentura, z.s. www.zeraagency.eu | Czech Republic |
| Genanvend Biomasse - danish biomass Recycling Association www.genanvendbiomasse.dk | Denmark |
| Solum Group www.solum.com | Denmark |
| Estonian University of Life Sciences Department of Water Management Institute of Forestry and Rural Engineering mi.emu.ee | Estonia |
| Finnish Biocycle and Biogas Association biokierto.fi | Finland |
| Hantsch SA www.hantsch.fr | France |
| INRAE Research Unit OPAALE www.inrae.fr | France |
| SYPREA www.syprea.org | France |
| VoxGaia www.voxgaia.fr | France |
| BASF SE - Performance Polymers www.basf.com | Germany |
| BGK - German Compost Quality Assurance Organisation www.kompost.de | Germany |
| BTA www.bta-international.de | Germany |
| Fachverband Biogas www.biogas.org | Germany |
| GKRS - Gütegemeinschaft Kompost Region Süd e.V. www.gkrs.online | Germany |
| AWN GmbH Biomassezentrum www.awn-online.de | Germany |
| RETERRA Service GmbH www.reterra.de | Germany |
| Hamburg University of Technology; Institute of Waste Water Managment & Water Protection BIOCONVERSION & EMISSION CONTROL GROUP (BIEM) www.eseia.eu | Germany |
| VHE Verband der Humus- und Erdenwirtschaft e. V. www.vhe.de | Germany |
| W.L. GORE & Associates GmbH www.gore.com | Germany |
| Deutsche Gesellschaft für Abfall- und Kreislaufwirtschaft e.V. www.dgaw.de | Germany |
| N3 Nachhaltigkeitsberatung www.N-hoch-drei.de | Germany |
| Gütegemeinschaft Kompost Region Bayern e.V. www.rgk-bayern.de | Germany |
| Compost Hellas www.compost.gr | Greece |
| Biosolids S.A. www.biosolids.gr | Greece |
| Hungarian Compost Quality Assurance Association / University of Gödöllö www.komposzt.hu | Hungary |
| Cré The Composting Association of Ireland www.cre.ie | Ireland |
| ARS AMBIENTE SRL www.arsambiente.it | Italy |
| Biofactory spa (Berco SRL) www.berco.org | Italy |
| Integrated Waste Management Research Group Scuola Agraria del Parco di Monza www.monzaflora.it | Italy |
| Italian Compost Consortium CIC www.compost.it www.compostabile.com | Italy |
| NOVAMONT SPA www.novamont.com | Italy |
| SUMUS ITALIA SRL www.sumusitalia.it | Italy |
| Società Agricola Agrisolar SRL | Italy |
| Alma Mater Studiorum University of Bologna, Dept. of Agriculture and Food Sciences https://distal.unibo.it/en/index.html | Italy |
| BVOR - Dutch Association of Biowaste Processors www.bvor.nl | Netherlands |
| Dutch Waste Management Association www.verenigingafvalbedrijven.nl www.dwma.eu | Netherlands |
| Elsinga policyplanning and innovation www.policyplanning.eu | Netherlands |
| Sirk Norge www.sirknorge.no | Norway |
| Grønn Vekst AS gronnvekst.no | Norway |
| GWDA Spólka Wodno Sciekowa Sp.Zoo www.gwda.pl | Poland |
| Polish Chamber of Waste Management (PIGO) www.pigo.org.pl | Poland |
| Environmental Engineering Department/ Fac. of Sci. and Techn./ New University of Lisbon www.fct.unl.ptn | Portugal |
| LIPOR www.lipor.pt | Portugal |
| MUSAMI - Operações Municipais do Ambiente www.musami.pt | Portugal |
| Valosur http://www.valorsul.pt | Portugal |
| Asociatia Romana a Compostului - Romanian Compost Association www.asociatiacompostului.ro | Romania |
| Asociatia Tehnopol Galati | Romania |
| Eko servis | Serbia |
| Zdroje Zeme, a.s. | Slovakia |
| Ministry for the Environment and Spatial planning www.mop.gov.si | Slovenia |
| Ategrus www.ategrus.org | Spain |
| Agencia de Residus de Catalunya www.arc-cat.net | Spain |
| REC - Red Espanola de Compostaje www.recompostaje.com | Spain |
| Avfall Sverige - Waste Management Sweden www.avfallsverige.se | Sweden |
| Umweko GmbH Umwelt und Kompostberatung www.kompost.ch www.kschleiss.ch | Switzerland |
| Carbon Clarity www.carbon-clarity.com | UK |