Temperature dependency of granule characteristics and kinetic behavior in UASB reactors

Abstract

When an inhibitory substrate, phenol, was treated under mesophilic conditions (25, 30, 35, and 40• C), the upflow anaerobic sludge bed (UASB) reactors at 30• C resulted in the greatest amount of biomass and the largest granule size, while the UASB reactors at 25• C resulted in the smallest granule size and the greatest amount of wash-out of sludge. The granule size tended to be negatively correlated with the amount of wash-out of sludge. With an increase in temperature, the kinetic constant k for anaerobic phenol degradation increased and the half saturation constant (K s ) decreased. The mass fraction of methanogens (f ) increased with increasing operational temperature in the UASB reactors and the activation energy (E a ) for acetate methanogenesis was larger than that for phenol acidogenesis in the batch reactors, indicating that the operational temperature imposes a more influential effect on methanogens than on acidogens. From the results of the activity of acidogens and methanogens (expressed in specific COD utilization rate), the rate-limiting step is phenol acidogenesis.

Aerobic granular sludge: Recent advances

“…Phenol was considered to be toxic to aquatic species (Brown et al, 1967;Kibret et al, 2000;Chung et al, 2003) and added an odor to drinking and food-processing water (Rittmann and McCarty, 2001). Aerobic granules have been applied to degrade phenol (Jiang et al, 2002(Jiang et al, , 2004aChou et al, 2004;Chou and Huang, 2005;Tay et al, 2005a,b). Tay et al (2004b) demonstrated that the granules degraded phenol at a specific rate exceeding 1 g phenol g − 1 VSS d − 1 at 500 mg L − 1 of phenol, or at a reduced rate of 0.53 g phenol g − 1 VSS d − 1 at 1900 mg L − 1 of phenol.…”

Degradation of phenol by aerobic granules and isolated yeast Candida tropicalis

“…Phenol is toxic to particular aquatic species (Brown et al, 1967;Chung et al, 2003;Kibret et al, 2000) and adds an odor to drinking and food-processing water (Rittmann and McCarty, 2001). Aerobic granules have been applied to degrade phenol (Chou and Huang, 2005;Chou et al, 2004;Jiang et al, 2002Jiang et al, , 2004aTay et al, 2005a,b). Tay et al (2004) demonstrated that their granules degraded phenol at a specific rate exceeding 1 g phenol/gÁVSS/day at 500 mg/L of phenol, or at a reduced rate of 0.53 g phenol/gÁVSS/day at 1,900 mg/L of phenol.…”

Expansion characteristics of an anaerobic fluidized bed reactor with internal biogas production

“…When the AFBR had reached steady state, a 50 cm 3 syringe was used to remove ∼5-10 cm 3 of bioparticles from the lower, middle and upper parts of the fluidizedbed zone. The d p value was determined using the method of image analysis, 31 δ was determined using the method of Shieh et al 32 and ρ mw and ρ bf were measured according to Huang and Wu. …”