Many workers have used two phase anaerobic processes during
the biomethanation studies on vegetable wastes. Zhu et al26
studied biomethanation of Vegetable wastes using anaerobic
sludge bed reactors (ASBR). The experiment was carried out at
mesophilic temperature conditions (350C), HRT was 4 days and
20 days for hydrolytic reactor(HR) and methanogenic
reactor(MR) respectively, OLR in HR and MR was 10/ g VS L
and 5 g VS L-1 respectively. The biogas yield was about 660/g
VS with 60±3% methane. Kamaraj27 studied vegetable market
waste biomethanation process using biphasic anaerobic systems.
The biogas and methane yields recorded were 511.8 and 352.7 l/
kg COD des respectively with a COD reduction of 75.6 % and
29.9 l/kg VMW fed. Rajeshwari et al28 studied biomethanation
of solid vegetable market waste using two-stage digester: 100 L
solid bed digester for hydrolysis and acidification and 24.6L
Upflow anaerobic sludge blanket (UASB) reactor for biogas
production. The COD reduction of 94% was achieved during
UASB reactor operation at organic loading rate of 19.6 kg COD
m day–3.