Anaerobic mesophilic sludge was used as a source of biological inoculum.
The sludge was obtained from a continuous anaerobic digester of
Bangkok Metropolis Water Quality Control Plant (Nongkham, Bangkok,
Thailand). The sludge was screened with a sieve of 500 μm (mesh no.
35) to remove material that would not be easily biodegraded and had
a volatile suspension solid (VSS) concentration of 25 g VSS/L