Psychrophilic anaerobic digestion biotechnology for swine mortality disposal.

Massé, D.I., Masse, L., Hince, J.-F., and Pomar, C. (2008). "Psychrophilic anaerobic digestion biotechnology for swine mortality disposal.", Bioresource Technology, 99(15), pp. 7307-7311. doi : 10.1016/j.biortech.2007.12.076

Abstract

The objective of this study was to investigate the feasibility of using psychrophilic anaerobic digestion in sequencing batch reactors 10 (PADSBRs) to co-digest grinded swine carcasses and swine manure slurry at 20ºC and 25ºC. The PADSBRs were operated on two-11 week and four-week treatment cycle lengths, which included the fill, react, and draw phases. Two carcass loading rates (CLRs) were 12 tested, that is 20 and 40 g of carcass per litre of manure, which were equivalent to 4 and 8 times, respectively, the normal mortality rate 13 on commercial farms. The PADSBR performance was compared to that of PADSBRs operated at 25ºC and fed manure only. 14 The addition of swine carcass to PADSBR feed did not affect the stability of the bioreactors at both CLRs. The performance of the 15 PADSBRs co-digesting swine carcasses was not statistically different from the control in terms of biogas production and quality. There 16 was no accumulation of volatile fatty acids in the bioreactors at the end of the treatment cycle. The mixed-liquor pH and alkalinity 17 remained within acceptable ranges for the anaerobic microflora. Also, there was no operational problem caused by the formation of 18 foam and scum in the system.