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Advanced Treatment Technology and Strategy 199

treatment is minimal. Another major advantage of this process is a lower foot-
print, especially when it is carried out in the CSTR process.
The schematic in Figure 4.2b shows actual layout and sizing of a system
for treatment of textile dyeing wastewater using the Fenton oxidation pro-
cess (Barbusi nski, 2009).

4.4 ELECTRO-FENTONADVANCEDOXIDATION
TREATMENT
Electro-Fenton is a process that is specifically designed to overcome some
of the drawbacks of the Fenton process. Two major drawbacks of the Fenton
process are the quantity of sludge produced and the imbalance in the
Fe/H 2 O 2 ratio, which leads to a lower rate of oxidation.
Electro-Fenton (Figures 4.3 and 4.4)(http://www.xh2osolutions.com)
is a process that addresses the issues pertaining to the two abovementioned
drawbacks by recycling ferrous ions in the Fenton reactor. The advantages of
recycling ferrous ions are the following:
1. Less sludge formation compared to advanced oxidation processes
(AOPs), because of lower use of ferrous catalyst.
2. Effective against high COD wastewater because there is better control of
molar ratio of Fe/H 2 O 2 .
3. Nonselective oxidation of organics as in Fenton oxidation.
4. Effective both as pretreatment for biological processes and as a stand-
alone treatment for low volume wastewater.

Catalyst Oxidant Oxidation
reactor

Treated water

Wastewater storage Oxidation
tank reactor

Exhausted catalyst
Figure 4.3 Layout of electro-Fenton process (http://www.xh2osolutions.com/).