The objective of this work was to evaluate the polluting potential from the remainings of effluents from biodigesters that operate with swine manure with the separation of the solid fraction and without the separation of the solid fraction, both under different hydraulic retention times (HRT). For the biodigestion trial, the effluents from semi-continuous biodigesters were processed with 15; 22; 29 and 36 days of hydraulic retention, with and without the separation of the solid fraction. In this part of the work batch biodigesters were used, which were kept in the operation as long as biogas was produced (60 days). It was evaluated: biogas production and quality and yield potential, the potential production per kg of total solids and volatile solids and chemical and biochemical demands for oxygen. Production potential found with separation of the solid fraction was 385 liter of CH4kg-1 of VS added and the effluent without the separation of the solid fraction was 117 liter of CH4kg-1 of VS added, for the shorter HRT (15 days) and production potentials of 74 and 18 liters of CH4kg-1 of VS added to the substrates with swine manure with the separation of the solid fraction and without the separation of the solid fraction respectively for the longer HRT (36 days).
methane; total solid; aerobic biodigestion
