Modification of the standard Neutral Ozone Decomposition Model
The modified Staehelin, Buhler, and Hoigné model was recalibrated and two rate constants, the rate constant of the initiation reaction of ozone decomposition of hydroxide ion and the rate constant of the promotion reaction of ozone decomposition by hydroxyl radical, were reestimated. The new estimates of these rate constants are 1.8x102M-1S-1 (initiation reaction) and 2x108 M-1S-1 (promotion reaction). The recalibrated -modified model was tested and validated by conducting experiments at different pH values and hydroxyl radical scavenger concentrations. Also, the effect of phosphate buffer as a hydroxyl radical scavenger was investigated at phosphate buffer concentrations of 10mM and1mM. Boijayanta K. Bezbarua1 and David A. Reckhow2 1Luit Infotech Pvt. Ltd., Chennai, India 2Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, Massachusetts, USA
D. Oemcke1 and J. Hans van Leeuwen2 1Provisor, Hartley Grove Urrbrae, South Australia 2Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, Iowa, USA
A two-Phase Computational Fluid Dynamics Model for Ozone Tank Design and Troubleshooting in Water Treatment
C.T.Ta and J. Hague
Application of an Experimental Design to Modeling of Ozone Bleaching Stage in TCF Processes
A.L. Torres, M.B. Roncero, J.F. Colom, J.A. Martinez, and T. Vidal
Ozonation of Polycyclic Aromatic Hydrocarbons in Water Solution
Jacek S. Miller and Dorota Olejnik
Influence of DOC on the Inactivation Effieciency of Ozonation Assessed with Clostridium perfringens and a Lab-Scale Continuous Flow System
W.A.M. Hijnen, E. Baars,T.G.J. Bosklopper, A.J. van der Veer, R.T. Meijers, and G.J. Medema
Kazuhiro Fujiwara and Takuya Fuji
Norijuki Igura, Masatoshi Fuji, Mitsuya Shimoda, and Isao Hayakawa
BIOLOGICAL SLUDGE REDUCTION WITH OZONE
Because of the expansion of purification plants, due both to the new development areas and to the stricter and stricter imposed limits, we have to be prepared to a dramatic increasing of produced sludge quantity.
We also have to add the more and more pressing social request not to dispose of the sludge in agriculture and consequently the demand to reduce the produced sludge quantity drastically.
The European and Italian guidelines are more and more demanding:
The cost of biological sludge treatment, that today already absorbs about 60% of the total exercise costs of an activated sludge plant, is going to grow dramatically!
At the moment, there are two ways to reduce the produced sludge in a biological process:
Oxysludge is the name chosen by our Firm to characterize the process used for the destruction of activated sludge more easily.
Picture 1 Different methods to insert destruction with ozone in a biological active sludge plant (Paul, 2003)
Consequent advantages are:
Concretely this process allows:
As to produce 1 Kg of ozone at current prices of electrical energy (0,092 €/kWh) and oxygen (0,103 €/kg) costs 1,8 €/kg O3, it derives that the cost to remove 1 kg of sludge at 100% si SS is equal to 0,108 - 0,144 €/kg.