The Synergistic Effect of Simultaneous Ultrasound Heating and Disintegration on the Technological Efficiency and Energetic Balance of Anaerobic Digestion of High-Load Slaughter Poultry Sewage

Regulations in force urge for thermal pre-treatment of post-slaughter waste prior to its anaerobic digestion. Increased interest in biomethane as a fuel in gas networks or vehicles of road transport forces the need to look for heating methods that are alternative to heat recovery from cogeneration. The goal of this study was to determine the synergistic effect of simultaneous ultrasound heating and disintegration on the technological efficiency and energetic balance of the anaerobic digestion of high-load slaughter poultry wastewater. The highest efficiency of anaerobic digestion was obtained for the ultrasound thermal pre-treatment (60 min, 90 degrees C, OLR = 2.0 gCOD/dm(3)). In this experimental variant, the biogas production rate reached 9.0 +/- 0.2 cm(3)/gCOD center dot h, biogas yield was 492 +/- 10 cm(3)/gCOD, and the biogas produced contained 69.8 +/- 1.4% CH4. Given the incurred energy outputs, the highest net energetic efficiencies, i.e., 5.92 +/- 0.43 Wh and 5.80 +/- 0.42 Wh, were obtained in the variants with the conventional thermal pre-treatment (60 min, 70 degrees C, OLR = 6.0 gCOD/dm(3)) and ultrasound thermal pre-treatment (60 min, 70 degrees C, OLR = 6.0 gCOD/dm(3)), respectively.

Automated summary

The regulations require thermal pre-treatment of post-slaughter waste before anaerobic digestion. The study investigates the use of simultaneous ultrasound heating and disintegration for the digestion of high-load slaughter poultry wastewater. Results show that the ultrasound thermal pre-treatment at 60 min and 90 degrees C achieves the highest efficiency of anaerobic digestion.