The effects of temperature, organic matter and time-dependency on rheological properties of dry anaerobic digested swine manure

• 60 °C results in similar flow behaviors for sludges with TS between 16.6% and 21.5%.
• Peptone reduced viscosity by acting as a water reducing and air entraining agent.
• The changes of shear stress over time can be simulated using a model.
• The first/second yield stresses can be evaluated using a time-dependent model.

An efficient way to avoid the pollution of swine wastewater is the application of dry anaerobic digestion, which needs rheological parameter for stirring and pipe designing. The rheological properties of this kind of sludge have been studied for many decades, yet their effects only solid concentration has been investigated widely. In this paper, the influences of temperature, organic and time-dependency on the efficiency of anaerobic digested swine manure were studied. The viscosity decreased with temperature arranged from 10 to 60 °C which caused increase in protein from 7.18 to 8.49 g/kg. 60 °C can make the digested swine manure with TS from 16.6% to 21.5% reach to the same rheology state. The added peptone decreased the viscosity because of its function of water-reducing admixture and air entraining mixture. Time-dependent experiment showed the decrease of shear stress over time. The first and the second yield stress of dry anaerobic digested swine manure were evaluated through time-dependent model.