10 research outputs found
Biological treatment of a synthetic dairy wastewater in a sequencing batch biofilm reactor: Statistical modeling using optimization using response surface methodology
In this study, the interactive effects of initial chemical oxygen demand (CODin), biomass concentration and aeration time on the performance of a lab-scale sequencing batch biofilm reactor (SBBR) treating a synthetic dairy wastewater were investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). The region of exploration for treatment of the synthetic dairy wastewater was taken as the area enclosed by the influent comical oxygen demand (CODin (1000, 3000 and 5000 mg/l)), biomass concentration (3000, 5000 and 7000 mg VSS/l) and aeration time (2, 8 and 18 h) boundaries. Two dependent parameters were measured or calculated as response. These parameters were total COD removal efficiency and sludge volume index (SVI). The maximum COD removal efficiencies (99.5%) were obtained at CODin, biomass concentration and aeration time of 5000 mg COD/l, 7000 mg VSS/l and 18 h, respectively. The present study provides valuable information about interrelations of quality and process parameters at different values of the operating variables
Kinetic modeling of carbon and nutrients removal in an integrated rotating biological contactor-activated sludge system
In this study, kinetics of biological carbon, nitrogen, and phosphorous
removal from a synthetic wastewater in an integrated rotating
biological contactor-activated sludge system was investigated. The
experimental data obtained from varying four significant independent
factors viz., hydraulic retention time, chemical oxygen demand for
nitrogen to phosphorus ratio, internal recirculation from aerobic to
anoxic zone and disks rotating speed were used for the process kinetic
modeling. In order to obtain the bioprocess kinetic coefficients,
Monod, first-order and Stover–Kincannon models were employed. As
a result, Monod and Stover–Kincannon models were found to be the
appropriate models to describe the bioprocess in the rotating
biological contactor-activated sludge system as the determination
coefficient for the first-order model obtained less than 0.79.
According to the Monod model, growth yield, microbial decay rate,
maximum specific biomass growth rate, and half-velocity constant
coefficients were found to be 0.712 g VSS/g COD, 0.008/d, 5.54/d and 55
mg COD/L, respectively. From Stover–Kincannon model, the maximum
total substrate removal rate constant and half-velocity constant were
determined as 15.2, 10.98, 12.05 g/L d and 14.78, 7.11, 6.97 mg/L for
chemical oxygen demand, nitrogen and phosphorus removal, respectively.
The kinetic parameters determined in this study can be used to improve
the design and operation of the biological contactor-activated sludge
system in full scale