Flavour Industry Wastewater Management C (1)


C

The Environmentalist, 26, 31–39, 2006
2006 Springer Science + Business Media, Inc. Manufactured in The Netherlands.

Flavour Industry Wastewater Management Case Study
FAYZA A. NASR* , NAGWA M. BADR and HALA S. DOMA
Water Pollution Research Department, National Research Center, Tahrir street,Dokki,Cairo, Egypt

Summary. This study is carried out to propose an appropriate treatment technology for wastewater discharged
from a flavor production factory. Industrial wastewater discharged from this factory ranges between 50–70 m3 /d
with an average value of 60 m3 /d. The major source of pollution in this factory is due to cleaning of the vessels
therefore the treatment has been carried out on the end-of pipe wastewater. The wastewater is characterized by high
values of COD, BOD, TSS and Oil and grease 4646, 2298, 1790 and 626 mg/l respectively. Primary sedimentation
of the wastewater for four hours reduced the COD, BOD, TSS and Oil and grease by 43, 47, 80 and 74%,
respectively. For the treatment of the produced wastewater, the biological treatment process such as activated
sludge, rotating biological contactor (RBC), up-flow anaerobic sludge bed reactor (UASB) have been selected.
The results from each treatment process proved to be efficient for the treatment of such wastewater. The treated
wastewater characteristics are in compliance with the Egyptian law which regulates the discharge of industrial
wastewater to the sewerage system. The RBC was selected and installed by the factory as it has the advantage of

low operating and maintenance costs. The factory RBC performance was monitored; characteristics of the treated
effluent in terms of oil and grease, COD, BOD and TSS were 27, 362, 139 and 95 mg/l, respectively.
Keywords: flavour, wastewater, treatment, rbc; uasb; activated sludge

Introduction
Food sufficiency is a major concern for the developing
countries. This explains the importance of food industry in Egypt in relation to other industrial sectors. The
food industry is of high production value and is important user of water. So food industry wastewater that is
discharged into water resources form a main source
of pollution. The characteristics of food-processing
wastewater exhibit extreme variation. The BOD may
be as low as 100 mg/l or as high as 100,000 mg/l.
The wastewater may be highly alkaline (pH 11.0)
or highly acidic (pH 3.5). Similarly, the volume of
wastes may be almost negligible in some industries,
but reaches one or more million m3 per day in other.
Food-processing wastewaters usually contain organic
matter (in the dissolved or colloidal state) in vary*Corresponding

author. E-mail: Fayzanasr@hotmail.com

ing degrees of concentration (Nemerow and Dasgupta,
1991). Since these wastewaters are characterized by
their higher concentrations of organic matter, pretreatment is required to produce an equalized effluent (El-Gohary and Nasr,1991). Biological processes
have long been used successfully to treat food industrial wastewater (Busten et al., 1990; Soheil, 1995).
Among the treatment techniques available, different
biological forms of wastewater treatment are indicated.
Activated sludge has been used successfully for many
years. However, it is energy consuming and requires
special skills for its operation and maintenance (Ni
and Nyns, 1993). Rotating biological contactors are
gaining increased acceptance due to its low operating and maintenance requirements, ability to operate
without nuisance from odor and flies and the relatively
high quality effluent despite variable loading conditions (Deborah et al., 1981; Metcalf and Eddy, 1991;
El-Gohary et al., 1987; Abou-Elela and El Kamah,

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Nasr, Badr and Doma

1998). Recently, the use of anaerobic technology for
treating organic wastewater has gained acceptance in
many countries. Among several anaerobic processes,
the up-flow anaerobic sludge blanket (UASB) is the
most widely applied for treatment of food industry
wastewater (Lettinga et al., 1991, El-Gohary et al.,
2000). It is an attractive alternative for the treatment of
industrial wastewater discharged from alcoholic and
soft drink bottling industries, fruit and vegetable canneries, dairy industry and brewing process (Lettinga
and Hulshoff Pol.,1986).This study deals with the
wastewater discharged from a flavor-production factory at 6th of October City. The factory employs 50
workers and is operated for one shift/day, six-days/
week. The factory produces natural and artificial flavors in liquid and powder forms. The major processes
at the factory are performed in batch modes. The factory discharges around 60 m3 /day mix of industrial
and domestic wastewater into the municipal sewer
system.
The main objective of the present study was to evaluate the use of an alternative biological treatment system for the treatment of flavor-production factory effluent, in order to permit its safe discharge into the
sewer system.

Laboratory analyses

The Physico-chemical characteristics were investigated to cover the following parameters: pH-value,
total suspended solids (TSS), total phosphate, COD,
total Kjeldahl nitrogen and oil & grease. The analyses
were carried out according to the APHA (1998).
Treatability options
Field survey and analysis of the wastewater discharged
from the factory indicated the presence of relatively
high concentrations of COD and BOD. The conventional and most commonly method for treating such
food industry wastewater is biological treatment.
The end of pipe wastewater was subjected to the
following treatment techniques as shown in Fig. 1:
Primary treatment
The wastewater is fed into a multifunction buffer/septic
tank (5 × 2 × 1.5 m) installed in the factory (Fig. 2).
The tank is divided into four equal chambers that allow
the flow of wastewater from one chamber to the next by
gravity. The first three chambers allow the separation
of solids and oil and grease, also the pH is adjusted by
using 70% sodium hydroxide in the fourth chamber.
The detention time in this tank is four hrs.

Materials and methods
Activated sludge treatment system
Sampling
Due to the considerable variation in the wastewater
quality over time, composite samples were collected
from the end of pipe effluent and the treatment systems.

Figure 1. Treatment processes.

Batch laboratory experiments were carried out using
activated sludge process. Two liters Plexiglas laboratory columns were used. The wastewater was inoculated with activated sludge from plant treating

Flavour Industry Wastewater Management Case Study 33

Figure 2. Buffer/Septic tank (15 m3 valume).

domestic sewage. The aeration was stopped daily to
let the sludge settle then the supernatant was drained
and the column was refilled again with the wastewater

until considerable amount of acclimatized sludge was
produced. To study the effect of aeration period on the
activated sludge, several experiments were conducted.
A fixed amount of sludge (3–4 g/l) was transferred
to a column to which the pretreated wastewater was
added. The phosphorus and nitrogen salts have been
added prior to the process to compensate the deficiency
of these nutrients. A detention time ranging from one
hour to twenty-four hours was examined. Dissolved
oxygen concentration was adjusted to maintain a minimum concentration of 2 mgO2 /l. Characterization of
the treated wastewater was carried out after 60 minutes
of settling.
Rotating biological contactor treatment system
(Lab Unit)

discs were mounted on horizontally shaft rotated
by a variable speed electric motor. Each compartment accommodated 8 discs of 14 cm diameter. The
(PVC) discs provide 0.95 m2 of total surface area
for microbial growth and were submerged in the
tank to about 50% of the disc diameter. The discs

were rotated at 4 rpm. The RBC is followed by a
five liters sedimentation unit. The RBC system was
fed continuously by pretreated wastewater. The biological unit was operated at hydraulic load around
0.03 m3 /m2 d. The average organic load was 0.63g
BOD/m3 /d.
Anaerobic treatment system
The experiment was performed in 1.7-liter volume
prespyx laboratory-scale UASB reactor with effective volume 1.5 liter (Fig. 4). The reactor was inoculated with 11.5 g VSS/l flocculent sludge from a
nearby anaerobic sludge treatment plant. The reactor
was equipped with solid-gas separators. The reactor
was fed continuously with the pretreated wastewater
at two different hydraulic retention times of 8 and
6 hrs.

Results and discussion
Production process

The rotating disc experimental unit (RBC), which is
shown in Fig. 3, consists of 5.19 L basin, divided
into four compartments of equal volume, 32 PVC

Figure 3. Schematic diagram of the experimental RBC system.

Figure 5 illustrates the main processes for flavors manufacturing. Diverse types of raw materials in powder or

34

Nasr, Badr and Doma
source of wastewater. Therefore, the treatment has to
be carried out on the end of pipe.
Wastewater characteristics

Figure 4. UASB reactor for anaerobic treatment.

Physico-chemical characteristics of the wastewater
discharged from the end of pipe effluent are presented
in Table 1 and illustrated in Fig. 6. The results showed
that the final effluent of the factory contains high concentration of COD and BOD; which reached 6920
and 3825 mg O2 /l, with average values of 4646 and
2298 mgO2 /l respectively. The final effluent was nearly

acidic in nature, the pH varied between 4.1 and 5.6;
the total suspended solids (TSS) ranged from 589 to
3268 mg SS/l with an average of 1790 mg/l. Also the
results showed a deficiency in the phosphorus and nitrogen concentration, the average concentrations were
4.6 mgP/l and 14.6 mgN/l. The wastewater contains
considerable amount of the oil & grease that reached
2186 mg/l with an average of 626 mg/l.
Primary treatment

Figure 5. Flavour manufacturing flowchart.

liquid forms are included in the flavors manufacturing,
for example tomato, onion, pepper, garlic lemon oil,
orange oil, sugar and salt etc. The powder flavors are
produced after being passed through four processes.
Grinding of crystal size raw materials is carried out
then steam treatment is performed to melt fatty ingredients, followed by blending the different components according to a set proportion and the product
is then packed before it is ready for distribution. The
liquid flavours production comprises only two steps,
the mixing process whereby ingredients are mixed according to specification then the product is packed and

distributed. The production processes clearly require
cleaning of the vessels used in each process. Water
is used for such cleaning and it carries pollutants before being discharged into the sewerage system. General cleaning of the processing area constitutes another

The wastewater is acidic and contains considerable
amounts of total suspended solids (1790 mg/l) and
oil & grease (626 mg/l) which may adversely affect
the microbial activity. Therefore, sedimentation and
pH adjustment were necessary prior to the biological
treatment step. This was carried out in a multifunction
buffer/septic tank with a detention time of 4 hrs. The
characteristic of the wastewater after the pretreatment
unit is recorded in Table 2 and illustrated in Fig. 7. The
oil & grease concentration was reduced by 74% and
reached 161 mg/l on the average. Also, a considerable
removal of COD and BOD occurred which reached
43% and 47% respectively and 80% of the TSS was
removed.
Total nitrogen and phosphorus concentrations are
14.8 and 4.3 mg/l respectively. The analysis of the pretreated wastewater showed that the ratio of BOD: N:

P is 100: 1.2: 0.4. This indicates that the concentration
of nitrogen and phosphorus is not sufficient for the biological treatment process, therefore, their concentration was adjusted by adding nitrogen and phosphorus
salts to reach the exact ratio (BOD: N: P, 100:5:1).
Activated sludge treatment system
The reactor was fed with the primary treated wastewater and operated at a detention time ranging from one

Table 1.

Performance of the treatment systems
UASB
1ry treated wastewater

Parameters∗

∗ Average

1st. load

2nd. load

%R

6.8 kgCOD/m3 ·d

%R

9 kgCOD/m3 ·d

%R

Egyptian law

7.0
144

95

7.4
1045

60

7.1
1038

61

6–9
1100

98

73.1

94

354

71

326

73

600

8.9

41

3.4

78

9

43

7.8

48

100

–
80

0.6
22

86
94

1.6
24

62
94

1
43

72
87

0.9
57

79
84

25
800

74

42

74

21

87

97

39

46

71

100

Unit

Raw wastewater

mgO2 /l

5.1
4646

5.2
2645

43

7.5
109

96

mgO2 /l

2299

1218

47

30

mgN2 /l

14.6

14.8

–

mgP/l
mgSS/l

4.6
1790

4.3
352

mg/l

626

161

results of 10 samples.

RBC(Lab unit)

%R

%R

Flavour Industry Wastewater Management Case Study 35

PH
Chemical oxygen
demand
Biological oxygen
demand
Total organic
Nitrogen
Total phosphorous
Total suspended
solids
Oil & grease

Activated sludge effluent

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Nasr, Badr and Doma

Table 2.

Characteristics of the treated wastewater using the RBC installed in the factory
Raw wastewater

Parameters
PH
Chemical oxygen
demand
Biological oxygen
demand
Total organic
Nitrogen
Total phosphorous
Total suspended
solids
Oil & grease
∗ Average

Unit

1ry. treated

% removal

RBC

% removal

Min. Max Avg Min. Max. Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. Avg.

Egyptian
law

4.13 5.6 5.1 4.8
5.5
5.2
mgO2 /l 3166 6920 4646 1978 3462 2645

38

50

43

5.1
127

7.2
543

6.4
362

94

84

86

6–9
1100

mgO2 /l 1572 3825 2298 752

52

53

47

25

385

139

97

79

88

600

1800 1218

mgN2 /l 13.4 23.5 14.6 11.5

20

14.8

14

15

-

2.3

8.4

4

80

58

71

100

mgP/l
mgSS/l

2
9.5 4.6 1.4
589 3268 1790 160

9.2
510

4.3
353

30
73

—
84

80

0.6
33

2.2
205

1.4
95

57
79

76
59

67
73

25
800

149 2186 626

161

116

40

93

81

5.2

64

27

94

60

77

100

mg/l

89

results of 10 time.

Figure 6. The variaation in the raw wastewater characteristics.

Figure 7. The variation in the pretreated wastewater characteristics.

Flavour Industry Wastewater Management Case Study 37

Figure 8. Effect of detention time on COD removal using activited sludge system.

hour to twenty-four hours using a MLSS of 3 g/l Fig. 8.
Analysis of the treated effluent indicated that the highest BOD removal was achieved at a retention time of
3 hours. Average residual values of COD, BOD, TSS
and oil & grease were 109 mgO2 /l, 30 mgO2 /l, 22 mg/l
and 42 mg/l, respectively (Table 1). These values are in
agreement with the standards set by the Egyptian law
for discharging treated wastewater into the sewerage
system.

values ranged from 80 to 303 mgO2 /l and from 30 to
146 mgO2 /l with an average of 144 and 73 mgO2 /l,
respectively. Oil and grease varied from 5 to 66 mg/l
with an average of 20.9 mg/l. The average of total suspended solids was 23.6 mg/l. From the available data, it
can be concluded that the treated wastewater is in compliance with the standards given by the Egyptian law,
which regulates the discharge of industrial wastewater
into the sewerage system.

Rotating biological contactor system (lab unit)
Anaerobic treatment system
The RBC was fed with the primary treated wastewater
at an organic loading rate of 0.03 kg COD/m3 /day. The
results of the analysis of the treated effluents are presented in (Table 1 & Fig. 9). COD and BOD residual

Figure 9. Characteristics of the treated effluent using RBC Lab Unit.

The UASB reactor was fed during the investigation
period with the pretreated wastewater. Two organic
loading rate were investigated namely 6.8 and 9 kg

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Nasr, Badr and Doma

Figure 11. The rotating biological contactor and the settling tank
in the factory.

Figure 10. Performance of the anaerobic treatment during different organic laods.

COD/m3 .d, at hydraulic retention time of 8 and 6 hours
respectively.
The results obtained during these chores are illustrated graphically in Fig. 10. Available data showed
that increasing the applied organic loading rate from
6.8 to 9 kg COD/m3 .d did not affect the COD removal
rate. During the two loads the average COD removal
ranged between 60% and 61%.The corresponding values were 1045 and 1038 mgO2 /l (Table 1). Also, the
BOD removal was not affected with changing the organic loading rates. The BOD average removal values
were 71% and 73%. The residual values of the total
suspended solids were 43 and 57 mg SS/l. From the
previous results, the 6 hours detention time was the recommended duration for the anaerobic treatment. These
values are in agreement with the standards set by the
Egyptian law for discharging treated wastewater into
the sewerage system.
Rotating biological contactor treatment system in the
factory
The RBC was selected and installed by the factory as
it has the advantage of low operating and maintenance
costs. The RBC was fed continuously with the effluent
from the pretreatment unit. It consists of a four stages
RBC. Each stage was filled with plastic packed materials in the form of rings which provide a total surface
area of 4000 m2 (Fig. 11). The discs were rotated at 3–5
rpm with approximately 45% of the surface area submerged in the wastewater. The total liquid volume of

the system was 6 m3 .The hydraulic load applied to the
RBC was 0.02 m3 /m2 .d. The water is dosed to the RBC
by rotating cups mounted on a large disc attached to the
main shaft. The factory RBC performance was monitored. Table 2 shows the characteristics of the treated
effluent. Residual values of COD and BOD ranged
from 127 to 543 and 25 to 385 mgO2/l with average
values of 362 and 139 mgO2/l, respectively. Corresponding average removal values were 86% and 88%.
The average percentage removal of total suspended
solids was 73%. The corresponding residual concentration was 95 mg/l. The average residual value of oil
and grease was 27 mg/l with 77% corresponding removal value. The characteristics of the treated effluent
are comparable with the results obtained by using the
lab unit RBC.

Conclusion
The obtained results using the activated sludge, rotating biological contactor and UASB technology proved
to be efficient for the treatment of wastewater discharged from a flavor production factory. The wastewater characteristics of each treatment process are in
compliance with the Egyptian law which regulates the
discharge of industrial wastewater to the sewerage system. The factory installed RBC proved to be efficient
and reliable on account of the characteristics of the
treated effluent as compared to the results obtained
from the lab unit.

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Flavour Industry Wastewater Management Case Study 39
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