Reduction of indicator and pathogenic microorganisms by psychrophilic anaerobic digestion in swine slurries

Abstract

The objective of this study was to evaluate the efficiency of a low temperature anaerobic treatment to reduce viable populations of indicator microorganisms (total coliforms, Escherichia coli) and the presence of selected pathogens ( Salmonella, Yersinia enterocolitica, Cryptosporidium and Giardia) in swine slurries from different sources. Experiments were carried out in 40 l Sequencing Batch Reactors (SBRs). Experimental results indicated that anaerobic digestion of swine manure slurry at 20 °C for 20 days in an intermittently fed SBR: (1) reduced indigenous populations of total coliforms by 97.94–100%; (2) reduced indigenous populations of E. coli by 99.67–100%; (3) resulted in undetectable levels of indigenous strains of Salmonella, Cryptosporidium, and Giardia. It can be considered as a promising method for reducing indigenous indicator and pathogenic microorganisms populations in liquid swine manure slurries.