Enhancement of reactor performance and pelletization by reactor modification in UASB system

Abstract

Reactor performance and pelletization characteristics by reactor modification in a UASB system were investigated. The modified lab UASB reactor with a settler comprising 50% of the total reactor volume showed better performance in removing soluble organics, as well as producing lower TSS effluents at higher loading rates. The reason for the improved performance may be the formation of a deep sludge blanket in the modified settler. The advantages of the modified reactor system are observable in methane production and alkalinity requirements. Furthermore, the pellets from the UASB system with a modified settler showed better settleability and biomass holding capacity. The chemical composition of the biopellets was a little different from the common bacterial formula of C₅H₇O₂N. Morphological characterization with SEM revealed many clusters, in terms of the physiological properties of hydrogen‐utilizing organisms, on the surface of pellets taken from the high hydrogen partial pressure zone in the modified reactor. This observation also suggests that the modified UASB system provides a better environment for the growth of hydrogen‐utilizing organisms.

Key words:

• Granular biopellets
• hydrogen partial pressure (P_H2)
• hydrogen‐utilizing organisms
• reactor configuration
• UASB