Physico-chemical Process for Fish Processing Wastewater Treatment

Abstract

The fishery products in Myanmar are from inshore, offshore, and inland fisheries and also from aquaculture. In Myanmar, there are 3 cold storages and 115 seafood processing factories. The effluents from those factories released into water bodies directly after little or no treatments have added to the environmental problem. For fish processing wastewater treatment, the optimization of coagulant dosage, pH and flocculants dosage was investigated. Ferric chloride (FeCl 3) was used as coagulant and polyacrylamides was for flocculants aid. The experiments were conducted at several dosages of 150-650 mg/L for coagulant and 15-65 mg/L for flocculant within the pH range of 3.0-11.0 to access the feasibility of the process. The process efficiency evaluation was based on the removal of COD, TSS, TDS, TS, turbidity, and odor. The best process condition was the coagulant dosage of 369 mg/L and flocculant dosage of 28.5 mg/L at pH 8.5 where 68 % COD removal and 50 % TSS removal were recorded. It is noticed that the turbidity and odor of the fish processing wastewater were also significantly decreased.

Full text

10th Regional Conference on Chemical Engineering
Sustaining Chemical Engineering Ingenuity and Breakthroughs Towards a Successful ASEAN Integration
06-07 November 2017  Hotel Benilde Maison de la Salle, Manila, Philippines
[1]
Physico-chemical Process for Fish Processing Wastewater Treatment
Lat Lat Tun1, Su Su Hlaing2*, Tint Tint Kywe3
123Department of Chemical Engineering, Yangon Technological University, East Gyogone, Insein Township,
Yangon, The Republic of the Union of Myanmar
*Corresponding author: suhlaing.ssh@gmail.com
ARTICLE INFO
ABSTRACT
Received (c/o RCChE 2017)
Received in revised form
(c/o RCChE 2017)
Accepted (c/o RCChE 2017)
Keywords
Fish processing wastewater,
Coagulation, Flocculation,
Wastewater treatment
The fishery products in Myanmar are from inshore, offshore, and inland fisheries and
also from aquaculture. In Myanmar, there are 3 cold storages and 115 sea-food
processing factories. The effluents from those factories released into water bodies
directly after little or no treatments have added to the environmental problem. For
fish processing wastewater treatment, the optimization of coagulant dosage, pH and
flocculants dosage was investigated. Ferric chloride (FeCl3) was used as coagulant
and polyacrylamides was for flocculants aid. The experiments were conducted at
several dosages of 150 – 650 mg/L for coagulant and 15 – 65 mg/L for flocculant
within the pH range of 3.0 – 11.0 to access the feasibility of the process. The process
efficiency evaluation was based on the removal of COD, TSS, TDS, TS, turbidity, and
odor. The best process condition was the coagulant dosage of 369 mg/L and
flocculant dosage of 28.5 mg/L at pH 8.5 where 68 % COD removal and 50 % TSS
removal were recorded. It is noticed that the turbidity and odor of the fish processing
wastewater were also significantly decreased.
I. INTRODUCTION
The environment is currently facing severe
eutrophication problems due to the various types of the
industrial effluents, agricultural run-offs and urban
domestic sewage etc. Among the industries, the fish
processing industries use the considerable amount of clean
water and then discharge the water contaminated by blood,
offal products, viscera, fins, fish heads, shells, skins, and
fined meat after processing [1, 2]. Environmental issues in
fish processing industries include water consumption and
wastewater generation, solid waste generation and by-
products production, and air pollution. The discharges of
fish processing industries can be toxic to man and other
aquatic life because of high dissolved and suspended
organic matter contents in the wastewater [3].
The fishery products in Myanmar are from inshore,
offshore, and inland fisheries and also from aquaculture.
The production of fishery products for 2014 - 2015 fiscal
year was 5,638,176.43 metric tons. Most of the fishery
products were primarily distributed for local food security
and the only 6% of total fishery production were exported.
In Myanmar, there are 3 cold storages and 115 sea-food
processing factories [4, 5].
The effluents from those factories released into water
bodies directly after little or no treatments have added to
the environmental problem. The quality of these effluents

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[2]
makes difficult to meet National Environmental Quality
(Emission) Guidelines, Myanmar (2015). Due to the
implementation of strict discharge limits, it is necessary to
study the wastewater treatment techniques that allow
obtaining water with quality requirements for its discharge
or reuse in the industrial process.
To reduce contaminant level, several techniques can be
used for treatment of the fish processing effluents. Many
researchers reported that the primary treatment such as
sedimentation, coagulation-flocculation [1, 6, 7, 8],
chemical and biological process (aerobic biological process
[2] or activated sludge treatment [3] or photobioreactor
with microalgae-containing microbiota [9]) and also
screening and dissolved air flotation methods [10] are
widely used in fish processing wastewater treatment to
reduce contaminated concentration.
Many studies have proved that the physico-chemical
process is the essential to treat fish processing effluents.
Therefore, the present study chooses coagulation-
flocculation process for more economic and environmental
friendly. The aim of this research work is to evaluate and
propose the optimum physico-chemical treatment for the
fish processing effluent. The specific objectives are to
optimize the process parameters using response surface
methodology (RSM) approach, to determine the removal
efficiencies of COD, TSS and turbidity of the treated
effluent and to provide the valuable information for the
wastewater treatment system in the fish processing
industries.
II. MATERIAL AND METHODS
1. Materials
The effluent sample was collected from only one
sampling point of the final discharge from fish processing
plant. To investigate the coagulation-flocculation process,
the coagulant of ferric chloride and the flocculant of
ployacrylamides were used. The pH of wastewater was
adjusted using NaOH (1 mol/L) and HCl (1 mol/L). The
chemicals were used without further purification. For
analysis of fish processing wastewater, the standard
methods for the examination were adopted for the
measurement of pH, temperature, turbidity, odor, total
solids (TS), total dissolved solids (TDS), total suspended
solids (TSS), chemical oxygen demand (COD). The used
equipment were Magnetic Stirrer (AGIMAN,
J.P.SELECTA, s.a., Spain) for physico-chemical treatment
efficiency; pH meter (OHAUS Corporation, STARTER
3100, USA) for pH and temperature measurement; TDS
meter (HANNA Instruments, HI-8634, Singapore) for total
dissolved solids; Turbidimeter (Lovibond Water Testing,
Germany) for turbidity; Thermal digester and Photometer
(Plaintest Ltd., APHA 5220-D Method, England) for COD
analysis.
2. Coagulation-flocculation Treatment
For the coagulation-flocculation tests, the inorganic
salt (FeCl3) was tested as coagulant and the polyacrylamide
was for flocculant aid. In order to see the effect of the
coagulant dose, several dosages (150 – 650 mg/L) were
studied at the pH influence that assessed in the range of 3.0
– 11.0 and the flocculant dosages (15 – 65 mg/L). For the
different process conditions, each test was filled with 200
mL of sample and the coagulant dose was then added
and/or the pH adjusted HCl (1 mol/L) or NaOH (1 mol/L).
After coagulation, the flocculation process was conducted.
The experimental procedure consisted of a rapid
mixing at 250 rpm for 1 minute and the coagulant was
added during stirring and then pH adjustment was
continued. The stirring speed was reduced to 50 rpm for 15
minutes. When the coagulation process was conducted, the

10th Regional Conference on Chemical Engineering
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[3]
flocculation process was followed at 100 rpm for 2 minutes
and, after that, in order to form flocs, it is stirred at 50 rpm
for 5 minutes. Finally, a sedimentation stage of 15
minutes allowed the flocs formed to be settled. The treated
water samples were collected for analysis. From Figure 1,
the supernatants obtained were then characterized in terms
of TS, TDS, TSS, COD, pH and turbidity.
Figure 1. Coagulation-flocculation test for fish processing
wastewater
III. RAW EFFLUENT CHARACTERISTICS
During the experiments running period, 50 L of
wastewater of fish processing plant were collected from at
the outlet of the process, after sieving and sedimentation
pre-treatments that they are subjected to. Standard methods
for the examination of wastewater were adopted for the
measurement of TS, TDS, TSS, turbidity, pH, temperature
and COD as can be seen in Table 1.
Table 1. Characteristics of raw effluent from fish processing plant
Parameter
Units
Values
Total Solids (TS)
mg/L
5300
Total Dissolved Solids (TDS)
mg/L
3300
Total Suspended Solids (TSS)
mg/L
2000
Turbidity
NTU
297.7
pH
-
5.9
Temperature
C
22.4
Chemical Oxygen Demand (COD)
mg/L
1187.5
IV. EXPERIMENTAL DESIGN AND DATA
ANALYSIS
In the present work, the coagulant, ferric chloride, and
the flocculant, polyacrylamides, were used in order to
destabilize colloids and to settle suspended particles at
various pH conditions. To verify the influence of coagulant
dose, pH and flocculant dose factors in the removal of TSS
and turbidity, we elaborate a central composite design,
factorial (23) with levels (-1, and +1) and three replicates at
the center point (0), which presented in Table 2. The
selected operating ranges for each factor were described
according to the values normally used in coagulation-
flocculation process and considering the initial wastewater
characterization.
Table 2. Levels of the experimental factors in the experimental
design
Factor
Unit
Coded Level
- 1
0
1
A: Coagulant (FeCl3)
mg/L
150
325
650
B: pH
-
3
7
11
C: Flocculant (Polyacrylamides)
mg/L
15
32.5
65
The coagulant dosage was a minimum value of 150
mg/L and a maximum of 650 mg/L. Since the center value
of flocculant dose was 32.5 mg/L, the upper and lower
limits of 65 and 15 mg/L, respectively, were chosen and the
pH values were between 3 and 11. The experimental design
matrix and processing data from each run were carried out
by Design Expert 7.0.0 software. Response surface method
was used for the best variant of coagulation-flocculation
based on removal of TSS and turbidity. In this work,
coagulant dosage (A), pH (B), and flocculant dosage (C)
were chosen as three independent variables, which resulted
in 17 trials.
The performance of the coagulation-flocculation
process for fish processing wastewater treatment was
optimized applying a factorial design. Using the results
from 17 experiments, the removal of TSS and turbidity
were predicted within the range of factors chosen. The TSS
removal results predicted by the quadratic model are
presented at each experimental point (Figure 2).
(
a
)
RAW
EFFLUENT
COAGULAT ION
FLOCCULATION
SUPERNATANT

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(a)
(b)
(c)
Figure 2. Response surface plots of TSS showing (a) the effects of
pH and coagulant dose, (b) the effects of pH and flocculant dose,
(c) the effects of coagulant and flocculant doses
However, the quadratic model was not fitted adequately
to the experimental data, in which the high p-value (p >
0.05) and also R2 value (0.68). Although the ANOVA
results show that inadequate model, the 50 % TSS removal
of fish processing wastewater could be attributed to the
variables, i.e., it could not be explained by the model. The
response surface graphs, see Figure 2, display the
statistically relevant effect of each factor on the response
and it is a practically mode to view the results. The
quadratic term of response seems to slightly affect on the
process parameters, but the interaction among factors was
shown to be almost statistically insignificant for TSS of the
response variables evaluated.
The model suggested that the condition of 385 mg/L
dosage of ferric chloride and 38.5 mg/L dosage of
polyacrylamides and pH 6.3 can remove the TSS value up
to 1028 mg/L. Additionally, the better performance was
achieved for TSS removal within the given range, which
explains the removal efficiency up to 50 %. It can be seen
that the model is slightly deviated from the experimental
data.
The supernatant turbidity removal efficiency is an
important denotation for the treatment efficiency in the
coagulaion-flocculation process. Using RSM, the effects of
factors on turbidity removal are known, the response can
be predicted and the optimum values can be determined.
The contour plots (Figure 3) generated from factorial
design, show the turbidity removal of the fish processing
wastewater as a function of pH, coagulant dose and
flocculant dose in this study. The statistical testing of the
model was shown as linear model of significant because
the p-value was 0.0374. The contour plots display the
statistically relevant effect of each factor on the response
and it is a practical mode to view the results.
Design-Exper t® Software
TSS
2170
1000
X1 = A: Coag. (FeCl3)
X2 = B: pH
Actual Factor
C: Floc. = 38.50
150.00
237.50
325.00
412.50
500.00
3.00
5.00
7.00
9.00
11.00
1020
1177.5
1335
1492.5
1650
TSS
A: Coag . (FeCl3) B: pH
Design-Exper t® Software
TSS
2170
1000
X1 = B: pH
X2 = C: Floc.
Actual Factor
A: Coag. (FeCl3) = 385.29
3.00
5.00
7.00
9.00
11.00
15.00
23.75
32.50
41.25
50.00
1030
1175
1320
1465
1610
TSS
B: pH C: Fl oc.
Design-Exper t® Software
TSS
2170
1000
X1 = A: Coag. (FeCl3)
X2 = C: Floc.
Actual Factor
B: pH = 6.31
150.00 237.50 325.00 412.50 500.00 15.00
23.75
32.50
41.25
50.00
1020
1165
1310
1455
1600
TSS
A: Coag . (FeCl3)
C: Fl oc.

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(a)
(b)
(c)
Figure 3. Contour plots of Turbidity showing (a) the effects of pH
and coagulant dose, (b) the effects of pH and flocculant dose,
(c) the effects of coagulant and flocculant doses
With the turbidity removal efficiency as the
response, the response surfaces of the linear model with
one variable kept at the best level and the other two varying
within the experimental ranges. The best conditions for
turbidity removal efficiency of 86 % were obtained as
follows: coagulant dosage of 385 mg/L, pH of 8.23 and
flocculant dosage of 35 mg/L. In this case, we have got the
results of 68 % COD, 50 % TSS and 86 % turbidity
removal efficiencies. Nevertheless, COD and TSS values
were not achieved to the environmental pollution protocol.
We need to conduct more test runs and another integrated
system.
The experiments on the effect of factors showed that
coagulant dose of 385 mg/L, flocculant dose of from 35 to
39 mg/L and pH of from 6.3 to 8.2 to get the maximum
removal of TSS and turbidity. The optimum condition can
be visualized graphically by the contours for the various
response surfaces in an overlay plot.
According to Figure 4, defining the optimization
criteria for the chosen response TSS (between 1100 and
1150 mg/L) and turbidity (between 40 and 42 ntu), the
shaded portion of the overlay plot was generated using the
Design Expert software.
(a)
Design-Exper t® Software
Turbidity
297
0.82
X1 = A: Coag. (FeCl3)
X2 = B: pH
Actual Factor
C: Floc. = 34.84
150.00 237.50 325.00 412.50 500.00
3.00
5.00
7.00
9.00
11.00
Turbidity
A: Coag. (FeCl3)
B: pH
20.5615
48.8597
77.158
105.456
133.754
Prediction
50.2319
Design-Exper t® Software
Turbidity
297
0.82
X1 = B: pH
X2 = C: Floc.
Actual Factor
A: Coag. (FeCl3) = 385.29
3.00 5.00 7.00 9. 00 11.00
15.00
23.75
32.50
41.25
50.00
Turbidity
B: pH
C: Floc.
21.844146.40570.9658
95.5267
120.088
Prediction
50.2319
Design-Exper t® Software
Turbidity
297
0.82
X1 = C: Floc.
X2 = A: Coag. (FeCl3)
Actual Factor
B: pH = 8.23
15.00 23.75 32.50 41.25 50. 00
150.00
237.50
325.00
412.50
500.00
Turbidity
C: Floc.
A: Coag. (FeCl3)
37.1778
48.2747
59.3716
70.4685
81.5654
Prediction
50.2319
Design-Expert® Softwar e
Over lay Plot
TSS
Turbidity
X1 = A: Coag. (FeCl3)
X2 = B: pH
Actual Factor
C: Floc. = 34.82
150.00 237.50 325.00 412.50 500.00
3.00
5.00
7.00
9.00
11.00
Overlay Plot
A: Coag. (FeCl3 )
B: pH
TSS: 1100
TSS: 1150
Turbidity: 40
Turbidity: 42

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(b)
Figure 4. Overlay plot for optimum region: (a) pH versus
coagulant dosage and (b) pH versus flocculant dosage
The optimum region corresponds to the areas, within
the range of the coagulant dosage from 369 to 439 mg/L,
flocculant dosage from 28.5 to 36.9 mg/L and pH from 8.5
to 8.8, respectively. This indicates that near the center point
in any of these variables, within the ranges studied resulted
in reducing efficiencies.
The results from this study are compared with other
ones from the literatures in Table 3. From literature reviews,
we find that the coagulation-flocculation method is one of
the most suitable processes to treat water or industrial
wastewater using different dosages and different types of
coagulant or floculants. Some literatures reported that they
use only coagulation-flocculation process or its integrated
with others such as dissolved air flotation unit.
R.O. Cristovao et al., (2014) reported removal percent
of TSS from fish processing wastewater were 62.6%, 72.4%
and 85.8% in the ferric chloride dosage of 100 mg/L, 200
mg/L and 400 mg/L, respectively. RSM design in fish
processing wastewater treatment was applied in the process
of biological treatment (activated sludge) [3] to obtain the
removal efficiency of 88 % dissolved organic carbon and
coagulation-flocculation process (chitosan as coagulant) [7]
to obtain the removal efficiency of TSS and COD between
70-90% and 26-30%, respectively.
Table 3. Comparison of TSS, COD and Turbidity removal
efficiencies obtained in this study with other results from
literatures
Types of
Wastewater
Treatment
Process
Dosage
Removal
Efficiency
References
Landfill
leachate and
Municipal
wastewater
Coagulation-
flocculation
470-2970
mg/L ferric
chloride;
100 smg/L
polyacryla
mide
79 % COD
93 %
Turbidity
90 % TSS
M.Verma et
al., 2016
(Engineering
and Material
Science)
Oil-Water
Emulsion of
refinery
wastewater
Coagulation –
DAF
50-1000
mg/L
(Alum,
Ferrous
sulphate,
Ferric
chloride)
87 % Oil
M.H.A.Megi
d et al., 2014
(Engineering
Sciences)
Pulp mill
wastewater
Coagulation-
flocculation
0 - 2100
mg/L
Aluminum
chloride
and 0 - 48
mg/L
polyacryla-
mide
99 %
Turbidity
J-P. Wang et
al., 2011
(Water
Research)
Fish canning
Wastewater
Sedimentation
Coagulation/
Flocculation –
Flotation
treatment
Inorganic
salts:
Al2(SO4)3 .
16H2O,
Fe2(SO4)3,
FeCl3,
CaCl2 and
PAX-18
99.2 %
O&G,
85.8 %
TSS,
25.2 %
DOC
R.O.
Cristovao et
al., 2014
(Water
Resources
and Industry)
Fish
Processing
Wastewater
Coagulation-
Flocculation
150 – 650
mg/L ferric
chloride
15 – 65
mg/L
polyacryla-
mide
68 % COD
86 %
Turbidity
50 % TSS
This Study
Design-Expert® Softwar e
Over lay Plot
TSS
Turbidity
X1 = C: Floc.
X2 = B: pH
Actual Factor
A: Coag. (FeCl3) = 384.88
15.00 23.75 32.50 41.25 50. 00
3.00
5.00
7.00
9.00
11.00
Overlay Plot
C: Floc.
B: pH
TSS: 1100
TSS: 1150
Turbidity: 40
Turbidity: 42

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V. CONCLUSION
The statistical experimental design and response
surface methodology were found to be efficient tools to
optimize some parameters. The most objectionable and
environmentally unfriendly pollutants of fish processing
wastewater were typically reduced COD by 68 % to less
than 380 mg/L, TSS by 50 % to less than 1028 mg/L and
turbidity by 86 % to less than 42 mg/L using coagulation-
flocculation process. The best conditions in the ranges
studied were found to be a coagulant dose of 369 mg/L and
flocculant dose of 28.5 mg/L at pH 8.5. Depending on the
purpose for the treated water, it might be necessary other
integrated systems.
ACKNOWLEDGMENT
This work is supported the facilities by Chemical
Engineering Department of Yangon Technological
University. The authors would like to their gratitude to
U Nyi Hla Nge Foundation provided a grant for this project.
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