The use of consecutive feeding was applied to investigate the response of the microbial biomass to a second addition of substrates in terms of biodegradation using batch tests as a promising altative to predict the behavior of the process.Anaerobic digestion (AD) of the slaughterhouse waste (SB) and its co-digestion with manure (M),various crops (VC),and municipal solid waste were evaluated.The results were then correlated to previous findings obtained by the authors for similar mixtures in batch and semi-continuous operation modes.AD of the SB failed showing total inhibition after a second feeding.Co-digestion of the SB + M showed a significant improvement for all of the response variables investigated after the second feeding,while co-digestion of the SB + VC resulted in a decline in all of these response variables.Similar patts were previously detected,during both the batch and the semi-continuous modes.