Breakdown of organic matter by bacteria in a sealed, oxygen-free tank. Produces biogas and digestate. The core reaction every plant on this site is built around.
The fibrous residue left after cane is crushed for juice. Mostly burnt in the mill's own boiler; the fines fraction too small for the boiler can go to a digester.
The raw gas leaving a digester — roughly half methane, half carbon dioxide, saturated with moisture and carrying hydrogen sulphide. Usable as boiler fuel, not as vehicle fuel.
Biogas that has been purified until it is almost entirely methane, at which point it is chemically interchangeable with fossil natural gas.
Compressed biomethane sold as fuel. In Indian policy the same product is called Compressed Bio-Gas.
Compressing finished gas into cylinders or cascades for road dispatch, used where no pipeline connection exists — which is most of India.
The balance of carbon to nitrogen in a feedstock. Too high and digestion stalls for want of nitrogen; too low and ammonia builds up and poisons the culture. Setting it is what recipe design means.
A bank of high-pressure cylinders mounted on a skid or trailer, used to move compressed gas from a plant to a dispensing station.
A measure of how much oxidisable organic matter a liquid carries. The cost driver in an effluent plant and the yield indicator in a digester — the same number read two ways.
The digester configuration we build: a continuously mixed tank fed at a steady rate, which keeps the culture uniform and the retention time predictable.
Everything left in the tank after the gas has come off. Separated into solid and liquid fractions and processed into organic fertiliser.
The document a bank or board needs before it will commit: feedstock study, process design, capital and operating cost, and financial model, in a form a lender can underwrite.
Mechanically opening sachets, bags and containers to recover the organic contents. Unavoidable on municipal waste and a common point of failure when it is skimped on.
The Indian regulation setting the standards organic fertiliser must meet to be sold, including nutrient content and permitted contamination limits.
Whatever goes into the digester. In this sector the term covers everything from press mud to market waste to a dedicated energy crop.
The Indian government scheme supporting conversion of cattle dung and organic waste into biogas and fertiliser, and one of the policy routes municipal projects can draw on.
A corrosive, toxic trace gas in raw biogas. Must be removed before compression or it destroys downstream equipment. We remove it in two stages rather than one.
How long material stays in the digester on average. Set by the slowest-digesting fraction in the mix, which is why one difficult co-feed can size the whole tank.
A fast-growing perennial energy crop used to fill seasonal gaps in feedstock supply, grown within the plant's own catchment.
The contracted agreement to buy the plant's output. Under SATAT this is what turns produced gas into bankable revenue.
The state fuel retailers that contract for CBG offtake under SATAT and dispense it through their retail networks.
The residue left after sugar cane juice is clarified — roughly three to four parts per hundred of cane crushed. The best-characterised biogas feedstock in Indian agro-industry.
Stripping carbon dioxide, hydrogen sulphide and moisture out of raw biogas until it meets fuel specification. We use water scrubbing.
Sustainable Alternative Towards Affordable Transportation — the Indian scheme under which oil marketing companies contract to buy CBG from independent producers at a notified price.
The supervisory control and monitoring system that runs the plant and logs every process variable. Fitted from day one on our builds, not retrofitted after a problem.
The high-strength liquid effluent from alcohol distillation, roughly eight to fifteen litres per litre of alcohol produced. A compliance liability that is also a dense feedstock.
A payment made by a municipality to have waste taken and treated. The only feedstock arrangement in the sector where the plant is paid to receive its input.
The standard capacity unit in this sector. Read carefully: it may refer to feedstock intake or to finished gas output, and the two differ by an order of magnitude.
The fraction of a feedstock's dry matter that bacteria can actually convert to gas. The number that matters for yield, as against total solids, which does not.
Purification by dissolving carbon dioxide and hydrogen sulphide into water under pressure. Robust, chemical-free in the main stage, and well suited to variable feedstock.
The requirement that a plant release no liquid effluent at all. Standard for Indian distilleries, and the reason spent wash is a cost centre before it is a feedstock.
A term we have missed?
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