PHYSICAL AND CHEMICAL TREATMENT OF WASTEWATERS 985
published by Gehr et al. in 2003. In this study the authors
presented and evaluated the different alternatives (with the
exception of chlorine, due to environmental regulations)
arriving at the conclusion that using the current process,
the economically viable alternative is UV, while if some
changes are made upstream, the use of peracetic acid could
be a viable alternative.
A study on the application of different AOPs to the treat-
ment of textiles, Kraft bleaching, photoprocessing, and phar-
maceutical wastewaters was published by Balcoglu et al. in- They conclude that the efficiency of the AOP process
used for a particular application depends upon the pretreat-
ment used, and concentrations and types of pollutants present
in the influent.
Adesina (2004) investigated the use of photocatalysis
for the treatment of spent industrial Bayer liquor and detox-
ification of paper-mill effluents, among others. The use of
sunlight as an energy source is also discussed. A compari-
son of different AOPs and chemical-treatment options was
conducted by Azbar et al. (2004) for the reduction of color
and COD from an acetate- and polyester-dyeing process.
They conclude that AOPs have better performances than
chemical-coagulation methods for the parameters stud-
ied. They also found that UV/H 2 O 2 achieved 99% and
96% COD and color removal, respectively. Their choice
from the economic point of view was the Fenton’s reagent
process. The removal of the drug diclofenac by means of
UV/H 2 O 2 was studied by Vogna et al. (2004), showing that
the proposed treatment was effective for the degradation of
the drug. The behavior of the process Fe(III)/Air/UV was
studied by Andreozzi and Marotta (2004) by using ben-
zoic acid as the molecule to be treated, with the goal of
developing kinetic models for this process. A study on the
treatment of cork-processing wastewater was published by
Acero et al. in 2004. They evaluated the use of different
combinations of UV, H 2 O 2 , and O 3 and Fenton’s reagent
and photo-Fenton processes for the effluent under study
and concluded that the best options that produce reusable
water are those involving ozone.
Broad reviews on oxidation technologies at ambient
conditions and on hybrid methods for wastewater treatment
were published by Gogate and Pandit (2004a, 2004b). Tabrizi
and Mehrvar (2004) present an interesting article on the inte-
gration of AOPs and biological processes, including recent
developments, trends, and advances in this field. A review
on the degradation of chlorophenols via AOP was published
by Pera-Titus et al. in 2004. Among their conclusions is that
although photocatalytic processes show higher half reaction
times, they do not require oxidants or further separation of
byproducts after the reaction.
Ding et al. (1996) present a review of catalytic oxi-
dation in supercritical water, including the reactions
involved, the processes available, a comparison with sub-
critical water oxidation, and an extensive review of the
catalysts available. Kritzer and Dinjus (2001) published
an interesting evaluation of the problems of supercritical
water oxidation, with discussion and suggestions for its
improvement.
Ultrasound Ultrasound is being studied as an alternative solu-
tion for environmental problems. This process works by gen-
eration of highly reactive oxidizing species, such as hydroxyl,
hydrogen, and hydroperoxyl radicals as well as hydrogen per-
oxide by means of ultrasound waves (Vajnhandl and Majcen
Le Marechal, 2005). In their review they include the use of
ultrasound in the textile industry and its wastewaters.Electrochemical Oxidation Panizza and Cerisola (2004)
published results on a series of experiments using an elec-
trochemical cell for the treatment of synthetic-tannery
wastewater using two different electrodes under various
experimental conditions, concluding that electrochemical
methods can be effectively applied for the final treatment
of these effluents, achieving total COD, tannin, and ammo-
nium removals.Electron-Beam Wastewater Treatment Water irradiation
with ionizing radiation generates several very reactive ions
and molecules. Getoff presents a review and the state of the
art for radiation-induced degradation of water pollutants
(1996). His group has studied the use of radiation for disin-
fection and decomposition of pollutants in water and waste-
water for years. Among the experimental factors proposed to
affect the efficiency of this process in pollutant degradation
are: form of radiation, energy, absorbed dose and dose rate,
pollutant concentration, pH, temperature, effect of oxygen
and ozone, presence of ozone and TiO 2 , and molecular struc-
ture of the pollutants (2002).
Pikaev et al. (2001) applied electron beams followed by
coagulation for the treatment of mixed distillery and munici-
pal wastewater; they conclude that the proposed scheme can
treat the effluent at lower cost than the biological and sedi-
mentation processes. In 2002 his group published pilot-plant
experiments using electron-beam and biological oxidation
for the treatment of dyeing wastewater. In this research they
conclude that the proposed method reached the desired efflu-
ent characteristics in about 8 hours of treatment, as compared
to 17 hours for biological treatment alone (Pikaev, 2002).
In collaboration with researchers from Korea, he also used
electron beams combined with coagulation, flocculation, and
biological processes for the treatment of paper-mill effluents.
This research concluded with the design of a commercial
plant for the treatment of 15,000 m^3 /day of wastewater with
80% of water reuse (Shin et al., 2002). In a final publication,
Pikaev (2002) presents data on the treatment of different
pollutants, including carboxylic acids, distillery slops, and
petroleum products. In this work the author presents an eco-
nomic evaluation of a commercial plant, concluding that the
treatment costs for the proposed technology are about half of
conventional methods.REFERENCESAcero, J.L., Javier Benitez, J. F., Heredia, J.B.D., and Leal, A.I. (2004). Chemi-
cal treatment of cork-processing wastewaters for potential reuse. Journal
of Chemical Technology and Biotechnology, 79(10), 1065–1072.
Adesina, A.A. (2004). Industrial exploitation of photocatalysis: progress, per-
spectives and prospects. Catalysis Surveys from Asia, 8(4), 265–273.C016_005_r03.indd 985 11/22/2005 11:25:21 AM