1. Design of Aqueous Phase Advanced Oxidation Processes for Removal of Atrazine
Ajinkya Deshmukh ( Department of Chemical Engineering and Sciences)
Dr. Daisuke Minakata (CEE) (ENVE 5503)
Introduction to Advanced Oxidation Process
 AOP: A set of chemical treatment procedures designed
to remove organic/ inorganic(sometimes) materials in
water and waste water by oxidation through reactions
with hydroxyl radicals Three major processes:
1) Ozonation as an AOP
2) Ozonation combined with Hydrogen-
Peroxide
3) UV light combined with Hydrogen-Peroxide
 In this process, the UV light that falls on the water
sample triggers the decomposition of hydrogen
peroxide in the water sample into hydroxyl radicals.
 These Hydroxyl radicals act as non-selective oxidants to
oxidize any reduced species ( SOC’s etc.)
 Determining the Quenching ratio is used as a prior
assessment of the AOP performance.
 The Quenching ration tells you the percent consumption
of the present Hydroxyl radical concentration by each of
the reduced species present in the water sample, or the
reduction in rate of target compound oxidation due to
the presence of other species in water sample.
Background
 Atrazine is primarily used as a herbicide to control the
growth of broad leaf weeds.
 The presence of Atrazine in water beyond a
concentration of 0.003mg/L
• Alters the way the basic reproductive system
works. Causes Liver, Kidney and Heart damage
• Uncertainty of toxicity with potential
carcinogenicity
 Suggested treatment goal at 0.003 mg/L based on US
EPA's MCLG and MCL.
We compared the AOP performance of the 5 ideal reactors
using the Simplified Pseudo Steady State model with the
following reactor data :
Inputs For H2O2/UV and Reactor Models
Wavelength of light, nm 254
Lamp power, kW 20
Energy use for H2O2 production, kWh/lb 4.9
Absorbance of NOM at 254 nm for a cell path length of 1 cm 0.014
pH 8
Concentration of target compound, mg/L 0.01
k HO• with target compound, M-1s-1 2.70E+09
Alkalinity, mg/L as CaCO3 400
DOC, mg/L 1.8
k HO • with DOC, M
-1
s
-1
3.90E+08
Conclusion/Results
 The treatment objective was achieved by all the reactor
models.
 Important model details: Number of tanks (n) = 20
(TIS),Peclet Number (Pe) = 35 (DFR)
 The Completely Mixed Batch Reactor (CMBR) gives a better
reactor performance compared to the other reactor models.
References
 Toxicological profile for Atrazine: U.S. Department of Health and Human
Services
 Evaluation of UVA, UVB and UVC Photolysis and Photocatalysis for the Remova
of Atrazine from Contaminated Water: Ziad Bushnaq, School of Civil and
Chemical Engineering, Environmental Engineering Department, RMIT
University, March, 2006
 Beltran et al ,1993
 AOP Simplified PSS Model Solver : Xin Guo, Daisuke Minakata, John C.
Crittenden
 Principles Of Water Treatment: Wiley Publications
 MDA Groundwater Monitoring Program Domestic Supply Well Baseline Study
TIS CMBR CMFR PFR DFR
InitialConcentration of Atrazine, (mg/l)0.01 0.01 0.01 0.01 0.01
pH 8 8 8 8 8
ReactorVolume (m3) 6 6 6 6 6
Flowrate (m3/second) 0.015 - 0.015 0.015 0.015
Hydraulic Detention Time (mins) 6.667 6.667 6.667 6.667 6.667
optimum initialH2O2dosage (mg/L) 17 14 23.33 16.66 17.5
optimum H2O2residue (mg/L) 15.5 10.833 20 14.33 15.2
optimum EE/O(kWh/m3) 0.466 0.4 0.933 0.433 0.45
Effluent concentration [R] (mg/l] 0.001 0 0.002 0.001 0.001
Tanks In Series (TIS)
Completely Mixed Batch Reactor
Completely Mixed Flow Reactor
Plug Flow Reactor (PFR)
Dispersed Flow Reactor (DFR)
C8H14ClN5