3.2. Biohydrogen (H2)
Experimental data also depicted the feasibility of fermentative
H2 production through food waste as substrate. The biodegradability
of food waste is mainly related to carbohydrate material, which
is the main substrate for H2 production (De Gioannis et al., 2013).
H2 production rate differed significantly with varying time. H2 production
was observed from 2nd day of operation and maximum H2
production rate of 21.52 ml/h was achieved on 19th day. This is an
indication for the lag in the metabolic activities due to higher substrate
concentration and the necessity of additional time for the
conversion of organic matter into H2 (Chandrasekhar and
Venkata Mohan, 2014b). Production rate was observed to fall gradually
after attaining a maximum value. The accumulation of volatile
fatty acids as by-products leads to drop in pH and this might
be reason for the observed decrement in H2 production after
26th day of operation (Chandrasekhar and Venkata Mohan,
2014b). Cumulative H2 production (CHP) increased till the end of
the SBES operation (Fig. 3). CHP was observed to increase with time
and showed 5400 ml H2 at end of the operation. CHP was observed
to stabilize after 26th day of SBES operation.