What is CBG? Understanding Compressed Biogas

Compressed Biogas (CBG) is a green, renewable fuel produced through the anaerobic decomposition of biomass and organic waste sources. It is chemically identical to commercially available natural gas (CNG), but unlike fossil fuels, it is entirely renewable and carbon-neutral.

The Feedstock Ecosystem

CBG can be produced from a wide variety of organic materials. This versatility makes it an incredibly robust energy solution. Common feedstocks include:

• Agricultural Residue: Paddy straw, wheat husk, and dedicated energy crops like Napier grass.
• Agro-Food Waste: Press mud and spent wash from sugar mills and distilleries.
• Animal Waste: Cattle dung and poultry litter.
• Municipal Solid Waste (MSW): The organic, wet fraction of urban waste.

The CBG Production Process

Converting raw organic waste into high-purity pipeline-quality gas involves a multi-stage engineered process:

1. Feedstock Pre-treatment: Raw waste is shredded, sorted, and mixed with water or digestate to create a homogenous slurry.
2. Anaerobic Digestion: The slurry enters a sealed digester tank (CSTR). In the absence of oxygen, bacteria break down the organic matter, producing raw biogas (roughly 55-60% Methane, 40% CO2, and traces of H2S).
3. Purification (Upgrading): This is the critical step. Raw biogas cannot be used in vehicles. It passes through advanced systems like VPSA (Vacuum Pressure Swing Adsorption) or membrane separation to strip away H2S, moisture, and CO2, resulting in biomethane with over 96% purity.
4. Compression & Bottling: The purified biomethane is compressed up to 250 bar into cascades, ready for transport, or injected directly into City Gas Distribution (CGD) pipelines.
5. Bio-Fertilizer Recovery: The leftover digestate is processed through a Solid-Liquid Separator (SLS) to yield high-quality dry organic manure and liquid fertilizer.