The biochemical methane potential (BMP) test for thickened sludge was evaluated at three different inoculum/substrate (I:S) ratios. The cumulative methane yield was 51.4 mL CH4/g VSadded at an I:S ratio of 1:1, 76.3 mL CH4/g VSadded at an I:S ratio of 1:3, and 21.9 mL CH4/g VSadded at an I:S ratio of 1:8. The greatest ultimate methane yield and methane production rate constant were achieved at an I:S ratio of 1:3, whereas the least was obtained at an I:S ratio of 1:8. The maximum methane production rate constant was 0.38/day and the minimum methane production rate constant was 0.0016/day. For the case of a lower I:S ratio, the biomass activity may be affected due to the low substrate concentration. On the other hand, for the case of higher I:S ratios, anaerobic digestion of thickened sludge was inhibited by higher concentrations of volatile fatty acids and lower pH.
- biochemical methane potential
- inoculum/substrate ratio
- methane yield
- thickened sludge
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology
- Biomedical Engineering