The biomasswas characterized
by an average VS/TS ratio of 60% VS/TS, beingmost of the organicmatter
in particulate form as indicated by the low VSS/VS (0.89%) and CODs/
COD (0.72%) ratios. During the experimental period,microalgal population
was mainly composed by green algae belonging to genus
Monoraphidium sp., Scenedesmus sp. and Stigeoclorium sp. and the diatoms
Nitzchia sp., Navicula sp. and Amphora sp. (Fig. 1).