Leftover school lunches will not go to waste in a joint experiment to be held in a Tokyo ward to turn the food into biofuel. Between 30 and 50 kilograms of food is left over daily at each of Tokyo’s 65 municipally run primary and middle schools. This waste is then incinerated. Tokyo Gas will spend about 100 million yen on the building and operation of the facilities for the experiment inside an office provided by the ward government. The firm plans to use a daily total of about 200 kilograms of waste collected from five or six local schools. To create the biofuels, enzymes are first added to the waste to saccharize it and separate solids from liquids. Bioethanol is extracted by alcoholic fermentation and distillation of the liquid. Methane is extracted by mixing the solids with waste fluids from the distillation process and fermenting the mix.
The ward plans for the ethanol collected from the waste to be used as a teaching aid for alcohol lamps and for the methane to generate electricity inside the experiment facility. It hopes to collect five liters of ethanol and 20 cubic meters of methane daily. This amount will reportedly provide enough energy for 70 alcohol lamps–equivalent to about six days’ worth of gas usage in an ordinary household.
