[Comparative study on biological methane potential and methanogen biodiversity in the anaerobic digestion of excess...

AP and DH excess sludge, sampled from AP and DH wastewater treatment plants respectively, were inoculated with their anaerobic sludge respectively and tested with biological methane potential (BMP) method. After the regression analysis with modified Gompertz and Michaelis-Menten model, it was found that although the maximum specific CH4 production rates of AP and DH anaerobic sludge were similar [74.21 and 51.99 mL x (g x d)(-1)], the half-saturation constants K(m) differed obviously (54098 and 19005 mg x L(-)), indicating DH anaerobic sludge exhibited a higher affinity for its excess sludge. At the end of both BMP tests, the concentrations of TSS and COD(T) decreased while the concentration of NH4(+)-N increased obviously, which were more significant at higher ratios of F/M. The T-RFLP analysis results were in accordance with BMP tests. After both BMP tests, the relative amount of diverse bacteria decreased while the relative amounts of Methanosaeta spp. (280 bps), Methanomicrobiaceae (80 bps) and RC-I (389 bps) increased obviously, which were more significant in DH-BMP test compared with AP-BMP.