Asian Journal of Chemistry;   Vol. 25, No. 15 (2013), 8817-8820
http://dx.doi.org/10.14233/ajchem.2013.15724
Treatability Studies on Organized Industrial District Wastewater
with Chemical Treatment, Fenton and Fenton-Like Processes
MELIKE YALILI KILIC
Department of Environmental Engineering, Faculty of Engineering and Architecture, Uludag University, 16059 Gorukle-Bursa, Turkey
Corresponding author: Fax: +90 224 4428243; Tel: +90 224 2942117; E-mail: myalili@uludag.edu.tr
(Received: 3 May 2013; Accepted: 30 August 2013) AJC-14055
Organized industrial districts are established to carry out the industrialization by minimizing the environmental problems. For this reason,
wastewater arises from different industries are treated by various treatment processes. In this study, the wastewater of organized industrial
district which is situated in Bursa city of Demirtas district, Turkey is treated by chemical treatment with various coagulants and Fenton
and Fenton-like processes. Al2(SO4)3·18H2O, FeSO4·7H2O and FeCl3·6H2O were used in chemical treatment studies and 72, 78 and 78 %
COD removal, 59, 41 and 50 % suspended solid removal were obtained, respectively. Fenton and Fenton-like processes showed high
COD (> 60 %) and suspended solid (> 75 %) removal performance on evaluated effluents.
Key Words: Chemical treatment, Fenton and Fenton like oxidation, Organized industrial district wastewater.
INTRODUCTION Because reclaimed water is an alternative water supply for
countries which suffer from water scarcity5.
Organized industrial districts (OIDs) are models which The main objective of this study is to investigate of treat-
have been used by State Planning Organization (SPO) in Turkey, ability of organized industrial district wastewater by chemical
to provide balanced development and regular urbanization, to treatment, Fenton and Fenton-like processes. For this purpose,
build industries that do not cause environmental problems1. various coagulants such as Al2(SO4)3·18H2O, FeSO4.7H2O and
Today in Turkey, 261 organized industrial districts have FeCl3.6H2O were used in chemical treatment. The results of
been become a legal entity. While the completed organized treatment studies are presented as a function of chemical oxygen
industrial district projects were only 70 until the year of 2002. demand (COD) and suspended solids (SS).
In the last 10 years, 77 organized industrial district projects
were completed and the total number of organized industrial EXPERIMENTAL
district projects increased to 147. The works on infrastructure Characteristics of Demirtas Organized Industrial
and treatment plant lending of 65 organized industrial districts District wastewater: Demirtas organized industrial district
have been continued in the investment program of 2012. Also, (DOID) is situated in Bursa, northwest of Turkey and provides
it is planned to have been completed of 15 organized industrial employment opportunities for 37,529 people. It contains
districts projects by the end of 20122. 414 factories from different industrial sectors such as textile,
Rapid growth of organized industrial districts has increased automotive and sub-industry, machine, electrical and electronic
the usage of water3. The discharged wastewater amount was tools, furniture and forest products, metal, food, chemistry,
190 million m3 in 2010, according to the results obtained from packing, petroleum products and other industries (Table-1).
the 134 organized industrial districts directorate, via Water, The domestic and industrial wastewaters of the DOID are
Wastewater and Waste Statistics Survey of 2010. The total discharged to Nilufer river by open and closed canals6. Demirtas
treated wastewater amount was 161 million m3 and advanced, Organized Industrial District (DOID) wastewater treatment
biological, physical or chemical treatment were applied on plant that meets the discharge criteria enforced by the Turkish
58.5, 40.1 and 1.4 % of treated wastewater, respectively4. Water Pollution Control Legislation7 having a flow rate 70,000
The applications of conventional treatment processes are m3/day and the DOID wastewater is treated by physical and
not sufficient to obtain the discharge criteria of wastewater. biological treatment.
Therefore, advanced treatment processes have been applied Raw wastewater samples used in this study were collected
and thus, reclamation and reuse of wastewater is provided. from the homogenization tanks of DOID and analyzed in
8818  Kilic Asian J. Chem.
TABLE-1 the samples were filtered on 0.45 µm Millipore membranes to
INDUSTRIAL CLASSIFICATION IN DOID6 remove MnO2. The pH and conductivity values were measured
Category Number of firms with a pH meter (Sartorius, Model PB-11, Germany) and a
Textile 267 WTW 315I conductivity meter (WTW, Germany), respectively.
Automotive and sub-industry 49 COD (closed reflux method) and suspended solid were mea-
Machine 10 
Electrical and electronic tools 3 sured in accordance with Standard Methods
8.
Furniture and forest products 6 
Metal 12 RESULTS AND DISCUSSION
Food 15 Chemical treatment studies: The effect of pH with
Chemistry 30 
various coagulants (Al2(SO4)3·18H2O, FeSO4·7H2O andPacking 3 
Petroleum products 2 FeCl3·6H2O) on COD removal was shown in Fig. 1. In chemical
Other industries 17 treatment studies, the COD removal increased until the pH 7
Total 414 and 9 whereas the removal of COD decreased beyond the pH
 7 and 9, when Al2(SO4)3·18H2O and FeSO4·7H2O were used,
accordance with Standard Methods8. Environmental charac- respectively. When FeCl3·6H2O was used, the maximum COD
terization of DOID wastewater is given in Table-2. The experi- removal was obtained at pH 4. The optimum pH values for
ments were carried out on the samples in order to remove COD the chemical treatment with Al2(SO4)3·18H2O, FeSO4·7H2O
and suspended solid. and FeCl3·6H2O were determined as 7, 9 and 4, respectively.
TABLE-2 
80
CHARACTERIZATION OF WASTEWATER 
Parameter Unit Value 70
pH – 8.96 60
COD mg/L 1008 
50
Suspended solid mg/L 460 
EC mS/cm 4.82 40
 30 Al2(SO4)3·18H2O
Chemical treatability studies: Chemical treatability 20 FeSO4·7H2O
experiments were performed at room temperature (20 ± 1 ºC)
10 FeCl3·6H2O
with 1 L samples in a Jar Test apparatus (Velp Scientifica,
Model FC6S, Italy). The pH of the samples was adjusted with 0 2 3 4 5 6 7 8 9 10 11 12
the addition of H2SO4 and NaOH. Samples were left for preci- pH
pitation for 1 h after 2 min of rapid mixing (120 rpm) and 15 Fig. 1. Effect of pH on COD removal during chemical treatment studies
min of slow mixing (20 rpm). Then, analytical analyses were
carried out on chemically treated wastewater. Fig. 2 shows the effects of Al2(SO4)3·18H2O, FeSO4·7H2O
Fenton and Fenton-like experiments: Fenton and and FeCl3·6H2O doses on COD removal. The optimum dose
Fenton-like experiments were conducted at room temperature of Al2(SO4)3·18H2O and FeSO4·7H2O were determined as 300
(20 ± 1 ºC) using varying FeSO4·7H2O-H2O2 (for Fenton experi- mg/L whereas the optimum dose of FeCl3·6H2O was 350 mg/L.
ments) and FeCl3·6H2O-H2O2 (for Fenton-like experiments) The dose of 300 mg/L of Al2(SO4)3·18H2O (at pH 7) and 300
dosages at varying pH values in order to determine optimum mg/L FeSO4·7H2O (at pH 9) resulted in 49 % of suspended
dosages give better results in COD and suspended solid solid and 37 % of suspended solid removal efficiency, while
removal. The pH was manually adjusted to desired range (pH FeCl3·6H2O removed 40 % suspended solid at a dose of 350
2-6) using 1 N sulphuric acid and/or sodium hydroxide before mg/L (at pH 4) (Fig. 3).
starting the experiments. During the determination of optimum
pH value, doses of FeCl3·6H2O, FeSO4·7H2O (supplied from 90
Merck) and H2O2 (supplied from Merck, 35 %, w/w) were
80
fixed at 200 mg/L. H2O2, FeSO4·7H2O and FeCl3·6H2O dosages,
change between 100 and 350 mg/L were used to decide chemical 70
dosages after the optimum pH was determined. Sedimentation 60
over 2 h was applied following the pH adjustment (7.5-8.0) 50
after 2 min of rapid mixing at 120 rpm and 20 min of slow 40
mixing were applied at Jar Test setup. COD and suspended Al2(SO4)3·18H30 2O
solid analyses were performed on wastewater supernatant, FeSO4·7H2O20
which was taken after 2 h precipitation. FeCl3·6H2O10
Analytical procedure: To decompose residual H2O2, 0
which interferes with the COD, the samples containing H2O2 50 100 150 200 250 300 350 400 450
were treated with MnO 9,102 powder . The concentration of Dose (mg/L)
residual H2O2 in the test solution was measured using test strips Fig. 2. Effects of coagulants dose on COD removal during chemical
(Merck Merckoquant Peroxide Test). Before each analysis, treatment studies
COD removal efficiency (%) COD removal efficiency (%)
Vol. 25, No. 15 (2013) Studies on Organized Industrial District Wastewater with Chemical, Fenton and Fenton-Like Processes  8819
60 70
50 60
40 50
40
30
Al2(SO4)3·18H2O 30
20
FeSO ·7H O Fenton process4 2 20
FeCl ·6H O Fenton-like process10 3 2
10
0
50 100 150 200 250 300 350 400 0
1 2 3 4 5 6 7
Dose (mg/L)
pH
Fig. 3. Effect of coagulants dose on suspended solid removal during Fig. 4. Effect of pH on COD removal during Fenton and Fenton-like
chemical treatment studies processes (CFeSO  = 200 mg/L, CFeCl  = 200 mg/L and CH O  = 2004 3 2 2
mg/L)
Eker and Çiner 11 applied the chemical treatment with
various coagulants, such as Al2(SO
70
4)3·18H2O, FeCl3·6H2O and
FeSO4·7H2O to the wastewater of Sivas Organized Industrial 60
District. They obtained 84 % COD and 55 % suspended solid 50
removal at a dose of 400 mg/L Al2(SO4)3·18H2O at pH 7. When
40
they used FeCl3·6H2O and FeSO4·7H2O at a dose of 250 mg/L
at pH 8, 76 and 73 % COD, 52 % suspended solid and 37 % 30
suspended solid removal were obtained, respectively. In Fenton process20
another study done by Çiner and Eker12, Al2(SO ) ·18H O,
Fenton-like process
4 3 2
10
FeCl3·6H2O and FeSO4·7H2O were used in chemical treatment
studies of Sivas organized industrial district and all these 0
50 100 150 200 250 300 350 400
coagulants proved high COD removal (> 70 %), but relatively FeSO4 and FeCl3 concentration (mg/L)
low TSS solid removal (around 50 %). Üstün et al.13 removed Fig. 5. Effect of FeSO4·7H2O and FeCl3·6H2O concentrations on COD
45-50 % COD and 84-96 % suspended solid with removal efficiencies during Fenton and Fenton-like processes (pH
Al2(SO4)3·18H2O, FeCl3 and Fe2(SO )  by adding anionic = 3 and CH2O2 = 250 mg/L)4 3
polyelectrolyte in chemical treatment studies.
Fenton and Fenton-like processes: The operating pH measurements. The residual H2O2 in the Fenton process can
and the dosages of FeSO4 and FeCl  are the parameters that consume K2Cr2O7, which leads to an increase in the inorganic3
18
affect the Fenton and Fenton-like processes. The optimum pH COD . Studies aimed at determining the optimum H2O2 dosage
has been observed to be 3 in Fenton processes14-16. Also, the were conducted at the previously determined FeSO4·7H2O and
oxidation potential of hydroxyl radicals (•OH) is known to FeCl3·6H2O dosages and pH values. Fig. 6 shows the COD
decrease with an increase in the pH17. removal efficiencies at different H2O2 dosages (between 100
In this study, the optimum pH value for the Fenton and and 350 mg/L) and constant FeSO4·7H2O and FeCl3·6H2O
Fenton-like processes was determined by adjusting the pH from concentrations. According to the Fig. 7, the optimum pH value
2-6. The resulting COD removal efficiencies were observed. and the H2O2 and iron salt dosages for the Fenton and the
As shown in Fig. 4, the maximum COD removal efficiency Fenton-like processes were determined as follows: pH = 3,
occurred at pH 3 for these two processes. The COD removal CH2O2 = 250 mg/L and CFeSO4 = 250 mg/L (61 % COD removal)
efficiencies for DOID wastewater at pH 3 (200 mg/L
80
FeSO4·7H2O, 200 mg/L FeCl3·6H2O and 200 mg/L H2O2
dosages) were 58 % for the Fenton process and 60 % for the 70
Fenton-like processes, respectively. 60
Other important operational parameters of Fenton and 50
Fenton-like processes are H2O2, FeSO4·7H2O and FeCl3·6H2O 40
concentrations. In these two processes, a constant H2O2 concen-
tration of 250 mg/L at pH 3 and dosages of FeSO 304·7H2O and Fenton process
FeCl3·6H2O between 100 and 350 mg/L were used to determine 20 Fenton-like process
the optimum concentrations. Fig. 5 shows the COD removal 10
efficiencies at a constant H2O2 concentration and the varied 0
FeSO4·7H2O and FeCl3·6H2O dosages. The optimum FeSO4·7H2O 50 100 150 200 250 300 350 400
and FeCl ·6H O dosages were determined as 250 mg/L for H2O2 concentration (mg/L)3 2
both Fenton and Fenton-like processes. Fig. 6. Effect of H2O2 concentration on COD removal efficiencies during
The other significant parameter in the Fenton and Fenton- Fenton and Fenton-like processes (Fenton process (pH = 3 and CFeSO4
= 250 mg/L) (61 % COD removal, 72 % suspended solid removal),
like processes is the H2O2 dosage. The H2O2 dosage influences Fenton-like process (pH = 3 and CFeCl  = 200 mg/L) (68 % COD3
the degradation process and excess H2O2 interferes with COD removal, 76 % suspended solid removal))
Suspended solid removal efficiency (%)
COD removal efficiency (%) COD removal efficiency (%) COD removal efficiency (%)
8820  Kilic Asian J. Chem.
TABLE-3 
PROCESS RESULTS FOR DOID WASTEWATER TREATMENT 
COD removal SS removal CAl (SO ) ·18H O CH O  C2 4 3 2 2 2 FeSO  CProcess pH 4
·7H2O FeCl3·6H2O
 
(%) (%) (mg/L) (mg/L) (mg/L) (mg/L) 
Chemical treatment with Al2(SO4)3·18H2O 7 72 49 300 – – – 
Chemical treatment with FeSO4·7H2O 9 78 37 – – 300 – 
Chemical treatment with FeCl3·6H2O 4 78 40 – – – 350 
Fenton process 3 61 72 – 250 250 – 
Fenton-like process 3 68 74 – 250 – 200 
 
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