Revista mexicana de ingeniería química
Print version ISSN 1665-2738
MENDEZ-CONTRERAS, J.M. et al. Behavior of the mesophilic and termophilic anaerobic digestion in the stabilization of municipal wastewater sludge (Part 1). Rev. Mex. Ing. Quím [online]. 2009, vol.8, n.3, pp. 283-290. ISSN 1665-2738.
The objective of this study was to evaluate the performance of the mesophilic and thermophilic anaerobic digestion process as an alternative for the biosolids production. Biological sludge from a municipal and industrial (brewery and pulp and paper) wastewater treatment plant using a UASB reactor was used. During the operation of the mesophilic batch system, the volatile solids (VS) were reduced from 60.3% (15.67 g/L) up to 37.5% (9.67 g/L) with 31 d of treatment time. The mesophilic process presented a stable operation reducing 38% of VS with 1.76 Kg VS m-3 d-1 of organic load feed fulfilling with the criterion of vectors attraction reduction. However, in mesophilic conditions, the digested sludge must be post-treated with a process of pathogenic microorganism inactivation because only remove low concentrations of pathogenic microorganism. The obtained results demonstrated that the process in thermophilic conditions (55°C) is capable to stabilize 3.9 Kg VS m-3 d-1 and to inactive the totality of fecal coliforms, Salmonella spp. and helminth ova fulfilling with the permissible limits for class A biosolids.
Keywords : mesophilic anaerobic digestion; thermophilic anaerobic digestion; municipal wastewater sludge.