Unison Solutions, Inc.
- Provides biogas conditioning and distributed generation systems. Applications include landfills, wastewater treatment facilities, dairies and food processing plants.
- http://www.unisonsolutions.com/

Envirogas
- In a joint-venture, they have installed and operate more than 30 biogas to energy plants, representing more than 60 MW of installed power. Vila Nova de Gaia, Portugal.
- http://www.envirogas.pt

Krieg & Fischer Ingenieure GmbH
- Planning, construction, operation and optimisation of biogas plants for agricultural, industrial and municipal inputs worldwide.
- http://www.kriegfischer.de/

Biotech Industries Ltd
- They purify methane from biogas, fermentation, and sewage gas. Based in Loughton, Essex, UK.
- http://www.biotech-ind.co.uk

Energy Security Union
- Offers pyramid permentation plants for separate production of biogas, and water and solid nutrients.
- http://www.biogas-esu.com

ASA GmbH
- German company that is specialized in the planning and construction of biogas plants.
- http://www.asagmbh.de/

Energy Recovery Associates
- Landfill gas company specializing in methane recovery.
- http://www.energy-recovery-associates.com/

Biogas Technology of LRZ Neukirchen
- Develops, designs, operates and provides technical support for biogas plants and its compounds for fermentation of organic waste and production of renewable energy.
- http://www.lrz-neukirchen.de/englisch/index-en.html

Proactive Energy Management
- We are consultant in energy. We manage the global chain Waste-Heat-Cold-Power. This includes: Cogeneration, Biomethanisation(digestors),Gasification We offer Consultancy services, EPC and Energy Contracting services (in constellation with partner) Con
- http://www.pr-en-ma.com

Environomics LLC
- Digester design and site management. Consulting: methane and electricity production from manure, on site odor control and the marketing of byproducts.
- http://waste2profits.com

PpTek Limited
- Manufacturer of regenerative siloxane and VOC removal systems for the biogas industry.
- http://www.pptek.co.uk

Gas Separation Technology LLC (GST)
- Enriching low quality methane sources such as landfill or coal mine gas by using pressure swing adsorption in combination with natural zeolites.
- http://www.gassep.com

Rentec Renewable Energy Technologies Inc.
- Biomass to biogas conversion using anaerobic digestion technology based on hydraulic mixing, maintenance free biodigester. Integrated turnkey solutions for agriculture, municipalities and other industries to process organic wastes into energy, high grade
- http://www.rentec.ca

Landfill Energy Systems (LES)
- LES supplies Caterpillar products with single-point responsibility for design, installation, service, parts, overhaul, training and operation.
- http://www.landfillenergy.com/

GBU mbH Biogas and Environmental Technologies
- Specializing in turnkey bio-gas plants and environmental technologies including hydraulic mixing anaerobic digesters, adsorption chillers and vacuum cascade evaporators.
- http://www.gbunet.de

EnergyXchange
- Western North Carolina nonprofit corporation formed to demonstrate the responsible use of landfill gas as an energy source for small enterprise.
- http://www.energyxchange.org/

The Corporation For Future Resources
- Anaerobic fermentation conversion systems for generating methane gas, carbon dioxide and anaerobic organic fertilizers.
- http://www.pipeline.com/~dglickd/CFR.html