International Journal of Analytical Mass Spectrometry and Chromatography, 2013, 1, 48-54 Published Online September 2013 (
The Combination of Coagulation-Flocculation Method and
the SCWO in the Waste Water Tr eatment Problems
Elmira Shakirovna Gayazova, Rustem Aytuganovich Usmanov, Farid Mukhamedovich Gumerov*,
Sergey Vladimirovich Friedland, Zufar Ibrahimovich Zaripov,
Farizan Rakibovich Gabitov, Rashid Zagitovich Musin
Kazan National Research University, Kazan, Russia
Email: *
Received July 18, 2013; revised August 22, 2013; accepted September 19, 2013
Academic Editor: Ilia Brondz1,2
1Department of Biosciences, University of Oslo, Oslo, Norway; 2R&D Department, Jupiter Ltd.
Copyright © 2013 Elmira Shakirovna Gayazova et al. This is an open access article distributed under the Creative Commons Attribu-
tion License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The influence of the degree of wastewater coagulation-flocculation and supercritical water oxidation (SCWO) methods
is considered. The regularities of changes in the composition of the purity of the reagents used and the parameters of
SCWO are established. Based on the results of chromatographic analysis of the effluent after washing the mass rape, it
is found that the achievement of the required parameters is achieved by treatment with a combination of coagulation-
flocculation method and supercritical water oxidation (SCWO). The necessity of combining techniques is insufficient
oxidation in SCWO lignin conducted at T = 400˚C and P = 25 MPa, T = 500˚C and P = 30 MPa. Effluent treatment of
process of styrene and propylene oxide “Nizhnekamskneftekhim” conducted by the SCWO, using an oxidant (H2O2),
and without an oxidant showed the possibility of cleaning without the use of an oxidizing agent in the process parame-
ters T = 500˚C, P = 30 MPa.
Keywords: Supercritical Water Oxidation (SCWO); Wastewater Treatment; Production of Pulp; Coagulation;
Flocculation; Chemical Axigen Demand (COD); Chromato Graphic Analysis
1. Introduction
In this paper, we have considered the possibility for super-
critical water oxidation (SCWO) treatment of wastewater
containing components, which are difficultly oxidizing.
Oxidative methods are increasingly used in wastewater
treatment. Most often ozone, chlorine, sodium hypochlo-
rite, hydrogen peroxide, at least—Fenton’s reagent are
used as oxidants. Each of these reagents has its pros and
cons, so the introduction of advanced oxidation processes
in water treatment practices using new oxidants is very
In recent years, a new method of industrial wastewater
treatment is rapidly developing, based on the use of the
supercritical water as an oxidant (T > 374˚C, P > 22.1
MPa) [1]. When the water is in supercritical conditions, it
behaves like a nonpolar solvent unlimitedly dissolving
organic substances and gases, but not dissolving the
mineral salts. In SCW almost complete utilization of in-
dustrial waste water in a reasonable time is achieved by
varying the temperature and concentration of the reac-
tants. The completeness and speed of reactions in super-
critical water (SCW) are provided by a molecular disper-
sion of the reactants. The kinetics and mechanisms of
chemical reactions in SCW depends on the temperature
and pressure (density) of the medium. Thus, even a slight
change in pressure SCW is accompanied by a significant
change in the density, essential for diffusion, viscosity,
and dielectric properties of the solvent medium.
The SCWO process goes with the release of heat if the
initial reaction mixture contains enough organic sub-
stances (10% - 25%) [2].
2. Experimental
Waste water after rapeseed mass washing that contains
hardly degradable polymer components (lignin, cellulose
Table 1) was selected as the object of the study.
The composition of the industrial wastewater after
washing is shown in Ta ble 1.
*Corresponding author.
opyright © 2013 SciRes. IJAMSC
Table 1. The composition of the industrial wastew ater after
rapeseed mass washing.
Ingredients 1 kg per 1000 kg of pulp
Organic part
Alkali lignin 400
Lignin dissolved 120
Hydroxy acids and lactones 300
Resin and fatty acids 90
Acetic Acid 60
Formic Acid 30
Polysaccharides 20
Methanol 8
Nitrogenous compounds 5
Methyl-sulfides compounds 2
Inorganic part
NaOH, bound to organic substances210
NaOH free 105
Na2S 50
Na2CO3 50
Na2SO4 45
Other sodium salts 50
Other minerals 20
рН 10 - 12
COD mgO/L. 16140
The main characteristic of organic compounds’ con-
tent reducing was chosen the COD method of analysis
for as an integrated efficiency index of the process. The
experiment was conducted on the installation (Figure 1),
which allows to realize the of rape wastewater SCWO
process in periodic mode at pressures up to 60 MPa and
temperatures up to 800 K.
The possibility for the treatment of the wastewater de-
scribed above was investigated using following oxidants:
hydrogen peroxide, manganese oxide (II), potassium
perchlorate and without oxidant.
The amount of oxidant was calculated using the waste-
water composition and COD values.
Reaction cell filled with “rape” drains, water and oxi-
dizer in the calculated quantities. The cell is equipped
with a high-pressure valve that allows the discharge of
the vapor phase after the completion of the process. The
over-heat of muffle furnace at the preliminary stage (to
550˚C - 650˚C) allows a quick attainment of the water’s
supercritical condition in the autoclave. By the end of the
process (after 10 minutes) the cell was taken out of the
furnace and cooled, cell’s content was analyzed for COD
[3,4]. The chromatographic analysis was also carried out.
Earlier studies for wastewater treatment using coagu-
lation and flocculation methods showed that processes
remove mostly compounds with a relatively high mo-
lecular weight (polymeric structures) [5].
Thus, to increase the efficiency of wastewater treat-
ment on the manufactures considered the combining of
Figure 1. The scheme for the SCWO carrying high-tem-
perature apparatus : 1, reaction cell, 2, muffle furnace, 3,
the hot junction of the thermocouple, 4, chamber of pres-
sure sensor, 5, pressure sensor PD100-DI, 6,7,11, secondary
devices TPM 101 for pressure and temperature, 8, electric
heater, 9, furnace’s stand, 10, insulation, 12, a collector of
water, 13, high pressure valv e.
coagulation-flocculation methods and SCWO can be
used. The main thing for the wastewater treatment ex-
periment by the coagulation method was the use of 30% -
iron sulphate (II, III) solutions, at an optimal pH range:
for Fe(OH)2 - 8.5 10.5, while for Fe(OH)3 from 4 to 6
and 8 to 10 [6].
Reagent solutions were added in the effluent liquid at a
concentration range from 0.5 to 15 g/l in terms of dry
matter. After the coagulation treatment, coagulum was
filtered with a filter fabric and the filtrate was analyzed
for COD, pH and light transmittance. Physicochemical
parameters of the filtrates after coagulation treatment are
shown in Table 2.
To improve the deposition of sediment, experiments
were performed with 0.1% flocculant solutions of dif-
ferent brands and different activity: anionic flocculant
“Praestol 2640” (Component company manufacture: “wa-
ter Him” Ltd.), cationic flocculant mark “Praestol 611”
(Component company manufacture: “waterHim” Ltd.) and
natural starch (Component company manufacture: “AO
Reahim” Ltd. GOST 10163-76-Reagents. Soluble starch.
TU) flocculant.
Coagulant solution Fe2(SO 4)3 with concentration of 5
g/L is added in the liquid effluent. Samples are mixed tho-
roughly for 2 minutes, and then the flocculant solution
with concentration of 1 to 3 mg/L is injected. Then the sam-
ples’ values of COD, pH and light transmittance are taken.
Physicochemical parameters of the wastewater after the
coagulant and flocculant treatment are shown in Table 3.
Copyright © 2013 SciRes. IJAMSC
Table 2. Physicochemical parameters after the coagulant
wastewater treatment (CW).
FeSO4/ Fe2(SO4)3(Component company
manufacturer: Closed Joint Stock Company
“Prominvest”,Iron (II) sulphate 7-water,
FeSO4 x 7 H2O,Clean,GOST 4148-78,
Iron (III) sulphate, 9-water (clean),
Fe2(SO4)3x 9 H2O, GOST 6981-94)
COD mgО/L рН
Light transmittance
(l = 5 mm,
λ = 750 nm)
Initial СW 16140 12.5 5
0.5 14384/16000 12.3/11.03 23/30
1 14215/16000 11.07/9.96 15/28
3 9424/6103 5.72/3.85 82/89
5 9920/6033 5.56/2.68 82/72
10 7440/8071 5.46/1.95 71/79
15 9920/7283 5.42/1.63 61/81
Table 3. Physicochemical properties after the wastewater
treatment using coagulant FeSO4/Fe2(SO4)3 (Component
company manufacturer: Closed Joint Stock Company “Pro-
minvest”, Iron (II) sulphate-7-water, FeSO4 × 7 H2O, Clean,
GOST 4148-78,Iron ( III) sulphate, 9-water (clean), Fe2(SO4)3
× 9 H2O, GOST 6981-94) and flocculants.
Dose of
(l = 5 mm,
λ = 750 nm)
1 4.82/2.66 8875/8203 72/33
2 4.81/2.55 9076/7812 71/24
Praestol 2640
“waterHim” Ltd.) 3 4,9/2,57 8838/7812 75/27
1 4.51/2.57 9172/7422 60/56
2 4.76/2.58 9273/8203 72/67
Praestol 611
“waterHim” Ltd.) 3 5.04/2.61 9076/7422 76/72
Starch (Component
“AO Reahim” Ltd.
GOST 10163-76 -
Reagents. Soluble
starch. TU)
1 4.76/2.60 8683/8203 75/70
3. Results and Discussion
We have studied two possible methods of wastewater
treatment of pulp from rape straw. Works with the origi-
nal waste water, as well as with previously untreated
water by coagulants and flocculants сarried out.
The results obtained in experiments using SCWO
waste liquid source are reflected in Figures 2(a)-(c)
show a decrease in (COD), but do not achieve the desired
performance values needed for biological purification.
Figure 2. (a) Schedule of changes the value of COD and pH
from concentration of oxidant H2O2 (Component company
manufacture: Himprom Novocheboksarsk, hydrogen per-
oxide, H2O2 (30%) at T = 400˚C, p = 24 MPa, CODpre =
16140 mgO/L; (b) Schedule of changes the value of COD
and pH from concentration of oxidant MnO2 (Component
company manufacture: STP TU COMP 1-251-10, MAN-
GANESE DIOXIDE, MnO2,clean) at T = 400˚C, p = 24
MPa, CODpre = 16140 mgO/L; (c) Schedule of changes the
value of COD and pH from concentration of oxidant KClO3
(Component company manufacture: “Soda-Chlorate” Ltd.
Potassium chlorate, TU 6-18-24-84, clean) at T = 400˚C, p =
24 MPa, CODpre = 16140 mgO/L.
Copyright © 2013 SciRes. IJAMSC
In previously conducted studies to analyze the com-
pleteness of organics removal were held chromatogra-
phy-mass spectrometric studies of the decomposition of
lignin-water-hydrogen peroxide by number of Japanese
scientists, which shows that the water-soluble part con-
tains the monomeric and dimeric lignin degradation pro-
ducts. Analysis using GC-MS was found 31 products [7].
These results clearly showed that the soluble portion in-
cludes various monomeric and dimeric compounds re-
sulting from the destruction and elimination of ester
bonds lignin propyl radical [2-4].
Reported studies indicate that more complete oxida-
tion are monomeric components, polymers reacting oxi-
dation SCWO conditions formed hydroxyl, carbonyl and
carboxyl groups without causing extensive oxidation to
gaseous components (CO2, CO) [8].
As a result discussed above, it would be logical to
combine the process of SCWO by coagulation-floccula-
tion treatment in the first stage.
From the data in Table 3 can be seen that the best
cleaning when FeSO4 (Component company manufac-
turer: Closed Joint Stock Company “Prominvest”, Iron
(II) sulphate-7-water, FeSO4 x 7 H2O, Clean, GOST
4148- 78, Iron (III) sulphate, 9-water (clean), Fe2(SO4)3x
9 H2O, GOST 6981-94) used as a coagulant observed
using this reagent in an amount of 10 g/L. In the case of
application of Fe2(SO4)3 best cleaning result is achieved
by using a reagent concentration of 5 g/L. Increasing the
concentration of the reagent solution is to move the waste
water from acidic to alkaline medium at a pH lower than
6 is dissolved precipitate, and consequently leads to an
increase of COD values.
As it is shown in the Table 4 data, the best clarifica-
tion of the wastewater occurs with the use of starch
(Component company manufacture: “AO Reahim” Ltd.
GOST 10163-76 - Reagents Soluble starch. TU) as floc-
culating additive with a concentration of 1 - 2 mg/L.
The efficiency of wastewater from pulp rape straw sig-
nificant influence raw water pH: at values close to neu-
tral, the degree of purification considerably lower than in
Table 4. The composition of industrial wastewater produc-
tion of styrene and propylene oxide of “Nizhnekamsk-
ingredients % mass.
ethylbenzene 2.5
acetophenone 1
methylphenylcarbinol 6.5
phenol 2.5
propylene glycol 12
molybdenum 0.2
other 35.3
COD 225000 mg О/L
the processing water with pH > 8. This effect is achieved
when higher dosages coagulant flocculation occurs
slowly precipitate bad precipitated and the supernatant
liquid is present finely dispersed suspension. This prob-
lem can be solved by increasing the initial pH of the
waste water to an optimum.
In general, waste water treatment, presented in this
paper is the best iron sulfate (III). Use of this reagent
results in a well-structured and floc sludge settling and
effective brightening of treated water is not required to
neutralize the water. Ferrous sulfate (II) also allows to
obtain satisfactory results, but at doses of 1.5 - 2 times
After the pre-treatment of wastewater by coagulation-
flocculation methods, waste liquid was subjected to the
same treatment in the North Caucasus Military District
installation. Processing results are presented in Figures
The liquid portion after the presented experiments was
analyzed by gas chromatography-mass spectrometry. The
study was conducted on the device (DFS) Thermo Elec-
tron Corporation (Germany). The method of ionization:
electron impact. The energy of the ionizing electrons was
70 eV, the ion source temperature 290˚C. Used capillary
column ID-BPX5, length—60 m, diameter—0.32-mm.
Carrier Gas-helium. Processing mass spectral data was
performed using the program “Xcalibur”. Purity of the
sample prior to entering the device diluted in chromato-
graphically pure acetone at a concentration about 1%wt.
Conditions for obtaining chromatograms:
1. The injector temperature—280˚C, the flow division
(split) —1:20.
2. Warming up the column was carried out in the pro-
gram mode: Initial temperature—60˚C (3 min), heating
rate 10˚C/min, final temperature—280˚C (30 min.)
3. The flow of carrier gas through the column—2 mL /
4. Temperature communication devices with a mass
5. The sample volume of 0.1 mL.
Below is a gas chromatography-mass spectrometry
analysis of the products SCWO Figures 4(a) and (b).
Analyzing data of chromatogram Figure 3a, can be
concluded that the above substances are degradation pro-
ducts of lignin not removed by coagulation and floccula-
tion in particular (2,3-dimethyl 2-cyclopentenone-1, ace-
tophenone, biphenyl, 4,5-dimethyl-1,3-dioxane-4-metha-
nol), fatty acid esters are believed to be the reaction
products of fatty and resin acids present in the composi-
tion of the initial waste water.
According to Figure 4(b) also detected decomposition
products of lignin and complex esters of polyhydric acids,
but their number is found in a smaller proportion, there-
fore, decreases the amount of organic matter in the sam-
Copyright © 2013 SciRes. IJAMSC
Figure 3. (a) Schedule of changes the value of COD and pH
from concentration of oxidant H2O2 (Component company
manufacture: Himprom Novocheboksarsk, hydrogen per-
oxide, H2O2 (30%), OST 301-02-205-99 amended. 1) at T =
400˚C, p = 24 MPa, CODpre = 6033 mgO/L; (b) Schedule of
changes the value of COD and pH from concentration of
oxidant MnO2 (Component company manufacture: STP TU
COMP 1-251-10, MANGANESE DIOXIDE, MnO2, clean)
at T = 400˚C, p = 24 MPa, CODpre = 6033 mg O/L; (c)
Schedule changes the value of COD and pH from concen-
tration of oxidant KClO3 (Component company manufac-
ture: “Soda-Chlorate” Ltd. Potassium chlorate, TU 6-18-
24-84, clean) at T = 400˚C, p = 24 MPa, CODpre = 6033 mg
content,% Name Formula
9.29 12.08phenol С6Н6О
9.84 3.56 2,3 - dimethyl 2 - cyclopentenone - 1С7Н10О
10.3 16.97acetophenone С8Н8О
15.045.76 biphenyl С12Н10
16.131.47 4,5 - dimethyl-1, 3 - dioxane - 4 -
methanol С7Н14О3
19.256.36 Tetradecanoic acid ethyl ester С16Н32О2
21.116.06 Ethyl 9 geksadekenoic acid С18Н34О2
21.267 Hexadecanoic acid ethyl ester С18Н36О2
22.9 8.58 Ethyl 9 oktadekenoic acid С20Н38О2
23.2111.02Cis-13 oktadekenoic acid С18Н34О2
24.597.49 Methyl cis -11- eicosenoic acid С21Н40О2
24.761.45 Methyl 19-eicosenoic acid methyl С22Н44О2
25.262.22 Methyl cis 11.14 - eicosenoic acid С21Н38О2
26.248.91 2 - dipropilpetiloic phthalate С24Н38О4
29.861.07 Н- tetrakozan С24Н50
Copyright © 2013 SciRes. IJAMSC
content,% Name Formula
5.29 11.93 Butyl acetate С6Н12О2
6.46 3.11 furfural С5Н4О2
9.53 13.6 phenol С6Н6О
10.39 14.63 acetophenone С8Н8О
16.2 25.04
4,5 - dimethyl-1, 3 - dioxane - 4 -
methanol С7Н14О3
17.32 25.87 3,5 - diacetillyutidin С11Н13NO2
22.92 2.85 Ethyl 9 oktadekenoic acid С20Н38О2
25.49 0.43 eicosane С20Н42
26.37 0.48 2 - metilnonadekan С20Н42
28.52 0.47 11 - (1-ethyl-propyl) geneykozan С26Н54
31.57 0.48 2,6,10,15 - metilgeptadekan С21Н44
Figure 4. (a) SCWO chromatogram, hydrogen peroxide
concentration 200 ml/L using as oxidate. (b) SCWO chro-
matogram, MnO2(Component company manufacture: STP
clean) concentration 70 g/L using as oxidate.
ples represented by a significant decrease in the values of
COD Figure 3(b).
In the case of wastewater from pulp rape straw prom-
ising is the use of manganese dioxide as represented by
the above dependences (3(a), 3(b), 3(c)) can be seen a
significant reduction in COD values, and therefore better
cleaning liquid waste. The undeniable advantage is also
the possibility of regeneration is represented by the ox-
After the process in the cell pellet is formed, a mixture
of manganese oxides in a lower oxidation state (Mn2O3,
Mn3O4), which can then be regenerated for re-use in the
cleaning cycle [9].
Regeneration of the manganese oxide can be produced
upon standing in air or O2 atmosphere at a temperature
above 300˚C [10].
Next, we have studied the possibility of wastewater
containing no polymer structures wastewater production
of styrene and propylene oxide of “Nizhnekamskneftekhim”
compositions are given in Table 4.
In consequence of the fact that the presented items
contain no polymeric component as compared to the
above described drain pulp. Consideration was given to
the data cleansing water only using the method of SCWO
[11]. However, since a large values of COD, the reaction
time was increased to 30 minutes. Also were built ac-
cording to changes in the values of COD from the dif-
ferent process parameters SCWO data presented in Fig-
ures 5(a) and (b).
Analyzing of depending concluded that this type of
waste water purification is possible without using an oxi-
dizing agent at the process parameters T = 500˚C, P = 30
MPa (Figure 5(b)), this solution is economically feasible
as excluded cost oxidant.
Figure 5. (a) Schedule of changes in the value of COD and
concentration of oxidant H2O2 (Component company ma-
nufacture: HimpromNovocheboksarsk, hydrogen peroxide,
H2O2 (30%), OST 301-02-205-99 amended. 1) (T = 400˚C, p
= 24 MPa); (b) Schedule of changes in the value of COD
and concentration of oxidant H2O2(Component company
manufacture: HimpromNovocheboksarsk, hydrogen per-
oxide, H2O2 (30%), OST 301-02-205-99 amended. 1) (T =
500˚C, p = 30 MPa).
4. Conclusion
Conducted research on wastewater treatment of various
industrial effluents found that to improve the quality of
treatment of waste washing rape weight required a com-
bination of the two methods of treatment—coagulation-
flocculation method and supercritical water oxidation
(SCWO) needed. Purification of effluents of industrial
production of styrene and propylene oxide by SCWO
process is available under the process parameters T =
500˚C, P = 30 MPa without using an oxidizing agent.
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