The anaerobic sludge was collected from a local municipal
wastewater treatment plant and screened by a sieve (diameter:
2 mm) to eliminate large particulate materials. It was heat pretreated
in a water bath at temperature of 100 C for 6 h to inhibit
the methane-producing bacteria activity (Ren et al., 2012). The
heat pretreated sludge was then used as inoculum for fermentative
hydrogen production