The volume of biogas produced in th

The volume of biogas produced in the batch experiment was
measured using a wetted-glass syringe method [15]. The volume
of biogas produced in the reactor experiment was measured using
gas counter (Fig. 2). Hydrogen and methane production were
determined by gas chromatography (GC, Shimadzu 2014, Japan)
equipped with a thermal conductivity detector (TCD) and a 2-m
stainless column packed with Unibeads C (60/80 mesh). The GCTCD
conditions followed those of Saraphirom and Reungsang
[16]. The hydrogen and methane volume in the biogas was
calculated using a mass balance equation [17]. The VFAs were
measured by high performance liquid chromatography (HPLC)
according to the method of Saraphirom and Reungsang [16]. The
COD, VS, and VSS were measured according to the APHA method