This paper presents a pilot project that investigates the possibility of producing biogas from a
mixture of water hyacinth and fresh rumen residue – replacing firewood as a source of fuel – to meet the
energy needs of a maternity facility in Niamey (Niger). The discontinuous-type installation (batch reactors) is
made up of six digesters measuring 5 m
3
each. The output during hot and cool seasons, 0.52 m
3
and 0.29 m
3
respectively of biogas per m
3
of digester per day, has met the energy needs of the maternity facility, estimated
at 8 m
3
of biogas per day. The study revealed strong seasonal variations: output during the hot season is
approximatively 1.8 times greater than it is during the cool season. Large quantities of water hyacinth, an
invasive plant present in Niger since 1986, are manually harvested in aquatic environments. The project is run
by a local NGO, the Groupe d’Initiative pour les Energies Renouvelables (GIER), and supported by UNICEF
and the Niger Basin Authority. The duration of the project is 8 months.