The science behind biogas transformation
Five stages turn a tonne of yesterday food waste into roughly a hundred cubic metres of methane-rich gas and six hundred kilos of biofertiliser. Here is exactly what happens at each one.
A continuous process on an 18 to 30 day cycle
Waste Input
Organic waste arrives
Anaerobic Digestion
Microbes break it down
Biogas Generation
Methane-rich gas forms
Capture and Purification
Collected and cleaned
Energy and Biofertiliser
Two products out
What happens inside each stage
Waste Input
Segregated organic waste, kitchen scraps, market rejects, crop residue, animal waste and agro-industrial sludge, is weighed at intake and screened for contaminants. It is then shredded and mixed with water or recirculated digestate to a slurry of roughly 8 to 12% total solids, the consistency the biology works best at. Feedstock is dosed on a schedule rather than dumped, because a stable organic loading rate keeps the bacterial population steady.
Anaerobic Digestion
Inside a sealed, oxygen-free vessel held at 35 to 40 C, four bacterial communities work in sequence. Hydrolysis breaks complex carbohydrates, fats and proteins into simple sugars and amino acids. Acidogenesis converts those into volatile fatty acids. Acetogenesis reduces them to acetic acid, hydrogen and CO2. Finally methanogens, the slowest and most sensitive of the four, turn that into methane. Retention of 18 to 30 days gives the last group time to finish.
Biogas Generation
Gas accumulates in the headspace and rises into a gas holder, a flexible membrane dome or floating drum that stores production between peaks of demand. Raw biogas is typically 55 to 65% methane and 35 to 45% CO2, with trace hydrogen sulphide and saturated water vapour. Composition is monitored continuously: a falling methane fraction is the earliest warning that the digester is over-fed or has gone acidic, usually days before any other symptom appears.
Gas Capture and Purification
Gas passes through a moisture knock-out to strip water vapour, then a scrubber, iron oxide media or a biological column, to remove hydrogen sulphide, which is corrosive to engines and pipework and is the source of the classic rotten-egg smell. For direct thermal use that is enough. For engines, bottling or grid injection, membrane or water-scrubbing upgrading strips CO2 as well, lifting methane content above 90% to produce compressed biogas.
Energy and Biofertiliser Output
The purified gas is piped to burners, boilers, dryers or a gas genset, or compressed and bottled as CBG for transport fuel. Meanwhile the digestate leaving the tank is separated: the liquid fraction goes to fertigation, the solid fraction is cured, screened and tested to become bagged biofertiliser. Both nitrogen and phosphorus survive digestion nearly intact, in a more plant-available form than the raw material they came from.
Why it works so well
Environmental benefits
Methane that would have vented from a landfill is captured and burned as fuel instead. Composting the same waste releases its carbon as CO2 with no energy recovery, landfilling releases it as methane with none either. Digestion is the only route that both prevents the emission and displaces a fossil fuel.
Efficiency metrics
Yield varies with feedstock, fats and oils are the richest and woody residue the poorest, but a well-run plant on mixed food waste is highly predictable once the biology has stabilised. Expect 60 to 110 cubic metres per tonne, and 1 cubic metre of biogas is worth about 0.43 kg of LPG in useful heat.
Technology advantages
Unlike solar or wind, biogas is dispatchable. It produces on demand, at night, in monsoon, from a fuel that arrives whether you want it or not. The feedstock is a waste stream you are already paying to remove, and capacity is added vessel by vessel.
Get Started with AeroShakti
A simple way to start turning your food waste into renewable energy.
CONNECT
Whether you are a hotel, hospital, residential community, institution, airport, food manufacturer or municipality, our team will assess your organic waste stream and recommend the most effective waste-to-energy solution. Every enquiry begins with a consultation focused on sustainability, operational efficiency and long-term value.
TRANSFORM
Our experts evaluate your waste generation, available space and operational requirements to design a customised collection and processing solution. From container placement and collection schedules to regulatory compliance and commissioning, we ensure a seamless implementation tailored to your facility.
BENEFIT
Your organic waste is transformed through advanced biomethanation into renewable biogas, green electricity and nutrient-rich organic fertiliser — reducing landfill dependence, lowering your carbon footprint and returning measurable value to your operation.
Interested in biogas solutions? Reach us today.
We model your feedstock, estimate your yield and tell you honestly whether the numbers work.