ABSTRACT
A cylindrical upflow filter packed with non-reticulated polyurethane foam, seeded with anaerobic sewage sludge and geared to biological treatment of dairy industrial wastewater, was used to determine the biomass content of the biofilm and suspended flora. This microflora is responsible for the conversion to methane and carbon dioxide of most of organic matter in wastewater. The methanogenic process reduces the COD of liquid wastes in more than 83
when operate at organic loading rate of 6 Kg COD/m3/d. Sequential sampling showed that biomass could be determined by measurement of volatile solids of each filter section. Those solids are related to filter geometry an produce accumulation of flocs (0.7g/l) in the bottom zone corresponding to liquid inlet.