Table 3 is used to outline the stoichiometric equation of fresh
Ulva. The analysis in Table 4 suggests for that for U. lactuca with
11% VS (1. Fresh), a theoretical maximum yield of 431 L CH4/kg VS
may be achieved. Using this methodology the theoretical maximum
production of methane, the portion of methane in the biogas
and the maximum production of biogas may be generated from
each sample (Table 5).
The samples which showed the most theoretical methane yield
were the unwashed samples (Table 5) which suggest there is biomethane
potential in the juices which may be removed when washing
the fresh material. However there are benefits from a practical
perspective in washing the seaweed prior to treatment in an anaerobic
process. Mechanical problems which may arise as a result of
debris and sand collecting in the digester system are minimised
through washing. Sand is also abrasive to moving parts (mixers
and pumps). Potentially salts may also be removed in this process
which will lead to a more stable digestion process.