Relative influence of process variables during non-catalytic wet oxidation of municipal sludge.
Individual and interactive effects of process variables on the degradation of fermented municipal sludge were examined during wet oxidation. The process was carried out at 220-240°C using 1:1-2:1 oxygen to biomass ratio and 300-500 rpm stirring speed. Response surface methodology coupled with a faced-centred central composite design was used to evaluate the effect of these variables on total suspended solids, volatile suspended solids and total chemical oxygen demand. Multivariate analysis was conducted for the initial and near completion stages of reaction: 5 and 60 min treatments, respectively. Temperature had the most significant effect on degradation rate throughout. During the initial stage the effect of mixing intensity was less significant than that of oxygen ratio. Mixing intensity did not influence degradation rate at the later stage in the process. During the near completion stage, the interaction of temperature and oxygen ratio had significant effect on sludge degradation.
Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Rotorua 3010, New Zealand. Electronic address: Saeid.Baroutian@scionresearch.com.
Saeid
S
Baroutian
Anne-Marie
AM
Smit
Daniel James
DJ
Gapes
D000704:Analysis of Variance; D001709:Biotechnology / Q000379:methods*; D002384:Catalysis; D002947:Cities; D005285:Fermentation; D009520:New Zealand; D010084:Oxidation-Reduction; D012044:Regression Analysis; D012722:Sewage / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D012722:Sewage; D014867:Water
Municipal sludge; Response surface methodology; Wastewater; Wet oxidation