Published in 2023. The figures and the policy are those of the time. Ask us where it stands today.
The Philippines blends 10% ethanol into gasoline under the Biofuels Act, and most of the local ethanol is distilled from molasses at sugar mills. Each litre of ethanol leaves behind ten to fifteen litres of spent wash: hot, acidic, dark brown, and with a chemical oxygen demand of 80 to 120 grams a litre. It is the mill's largest environmental problem and its largest unused fuel.
Compiled in September 2026 from the releases of the time, with the revisions the agencies have published since. Nothing here is a forecast.
What the wash is
Spent wash is the residue of fermentation and distillation: water, unfermented sugars, yeast, organic acids, potassium and the colour compounds of molasses. It cannot be discharged, it cannot be spread on land in the quantities a distillery makes, and it does not evaporate cheaply. Distilleries have historically held it in lagoons, which is a slow, uncontrolled digester that gives its methane to the air.
What a digester does
An anaerobic digester takes the same wash and turns the organic load into biogas in a sealed tank under controlled temperature. The gas is roughly 60% methane and burns in the distillery's boiler in place of bagasse or bunker fuel, or in an engine for power. The treated wash comes out with most of its organic load gone, ready for the aerobic polishing that makes it dischargeable or for use as a potassium-rich irrigation water where the rules allow.
The numbers that decide it
The volume and the strength of the wash, which set the size of the tank.
What the boiler burns today and what that fuel costs, which sets the value of the gas.
Where the treated wash goes, which sets the size of the polishing stage.
Why it is done at the mill
The wash is hot when it leaves the column, the boiler is a hundred metres away, and the milling season and the distilling season overlap. Nothing has to be transported. A digester at a distillery is the rare energy project in which the logistics are already solved.
The page for sugar mills and distilleries sets out the whole site, bagasse and wash together.
A digester on the site, sized to the residue and run by us, is what we offer under biogas digester leasing. Tell us what the site produces and an engineer replies with the data we need.
The next step
If you have organic waste or a boiler and want to know what it is actually worth, tell us what the site produces and what it costs you today. An engineer replies with the first step.
Tell us about your site →