Effect of Pressure on the Removal of NH₃ from Hydrolyzed and Pre-Fermented Slaughterhouse Waste for Better Biomethanization

• Main Authors: Aleš Zver, Rajko Bernik, Rok Mihelič
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Energies
• Subjects: slaughterhouse waste; hydrolyzes; pressure; pilot-scale; ammonia; biogas
• Online Access: https://www.mdpi.com/1996-1073/12/10/1868

Slaughterhouse waste (SW) is potentially a good source of biomethane; however, its excessive ammonia content quickly causes inhibition of microbial processes. Our aim was therefore to remove ammonia from SW before putting it into a biogas reactor. Experimental 120 L pressure container was constructed to observe NH₃ removal from diluted slaughterhouse waste at constant air flow of 144 NL/min, temperature 130 °C, and at different pressures: 300 kPa, 600 kPa, and 900 kPa. SW was first allowed to hydrolyze for 14 days at 38 °C. The SW was diluted with water (DSW) to 8.4% dry matter (DM) and forcibly aerated for 334 min. From the DSW, 0.7%, 3.8%, and 9% of initial total N were removed at 300 kPa, 600 kPa, and 900 kPa, respectively. However, the C/N ratio changed only slightly, from the initial 4.38 to 3.17, which is not a promising result for biomethanization. Further research on the presented system with the addition of bases might be promising to remove more ammonia.