Photo 1 shows the batch system
The digester was stirred manually by shaking the 500 ml bottles. A pH tape was used to
measure the pH before the food refuse was added into the bottles and after the digestion
period. It ranged from 6 -8. The temperature of the slurry was read daily using a
thermometer that was inserted into the digester. The ambient temperature was not
measured. The pressure of the gas produced was recorded daily using manometer filled
with colored water. The pressure of biogas produced was measure and recorded as the
displaced water in the manometer column. The biogas generated was measured by
downward displacement of water. The volume of water displaced was measured daily.
The highest volume for given day of the experiment was over 708 mm on the 4th day.