The boundary of the lifecycle starts from the collection of water
hyacinth to the consumption of products. GHG is emitted from the
consumption of fossil fuel and coal-derived electricity. The emission
of GHG is reduced by replacing water gas and chemical
fertilizer with biogas and organic fertilizer, respectively. The calorific
values of biogas and water gas are 23.36 MJ m3 and
10.46 MJm3, respectively. According to their calorific values, a unit
of biogas can replace 2.23 units of water gas. The biogas plant
produces 245,437.5 m3 per year, which is equivalent to
548,128.11m3 ofwater gas. Since the CO2 emission rate ofwater gas
is 45 kg GJ1, or 0.4707 kg m3, about 258 tons of CO2 can be
annually reduced by substituting water gas with biogas.