3.3. Water Hyacinth as Fermentable Material
Figure 9 shows the gas production from water hyacinth.
The average digester temperature was about 32ºC. It shows
that the hydraulic retention time for water hyacinth is about
36 days and gas production starts at the 4th day. Maximum
gas is produced at the 26thand 27thwhich is0.012 m3.four slots of hydraulic retention time. In first slot from 0-10
days about 12% gas is produced. From 11-20 days gas
production increases to about 27%. In the third slot from
21-30 days the maximum gas is produced which is about
46%. Finally, from 31-36 days gas production reduces to
about 13%and gas production almost ceases after the 36 th
day. Constituents of biogas from water hyacinth were
found very similar to that from cow dung (Fig. not shown
here).