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IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

ENHANCED COAGULATION EFFICIENCY OF
MORINGA OLEIFERA SEEDS THROUGH SELECTIVE

OIL EXTRACTION

Suleyman A. Muyibi*, Saad A. Abbas**, Megat Johari M. M. Noor**, Fakrul
Razi Ahmadun***

*Department of Biotechnology Engineering, Faculty of Engineering, International Islamic
University Malaysia, Jalan Gombak 53100 Kuala Lumpur Malaysia.

**Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia,
Serdang, Selangor, Malaysia.

***Department of Chemical and Environmental Engineering, Faculty of Engineering,
Universiti Putra Malaysia, Serdang, Selangor Malaysia.

email: suleyman@iiu.edu.my or engrmuyibi@yahoo.com

Abstract: In this laboratory based study, varying quantities of oil, corresponding to
20 % w/w, 25 % w/w and 30 % w/w kernel weight extracted from Moringa oleifera
seeds ( S1, S2, S3) respectively were applied in the coagulation of model turbid
water (kaolin suspension) and turbid river water samples from River Batang Kali
and River Selangor in Malaysia to determine the percentage oil removed which
gave the best coagulation efficiency. For model turbid water (kaolin suspension)
coagulation of low turbidity of 35 NTU, medium turbidity of 100 NTU and high
turbidity of 300 NTU, sample S2 gave the best turbidity removal corresponding to
91.7%, 95.5% and 99% respectively. Application of sample S2 to River Batang
Kali with low initial turbidity of 32 NTU and high initial turbidity of 502 NTU
gave a highest turbidity removal of 69% and 99% respectively. Application to
River Selangor with medium initial turbidity- of 87 NTU and high initial turbidity
of 466 NTU gave a highest residual turbidity' of 94% and 98.9%, respectively.

Key words: Moringa oleifera seed, selective oil extraction, coagulation, model turbid
water (kaolin suspension), river water, turbidity removal.

1. INTRODUCTION

Many researchers have reported on various uses of Moringa oleifera seed extract as a
primary coagulant in turbidity removal [1-3].
Previous studies have focused mainly on the efficiency of Moringa oleifera seed
extract as a coagulant [4-6]. Some researchers have focused on the physical factors
affecting the use of Moringa oleifera seeds in the coagulation of model turbid water
as well as the active agents in the seed extract and mechanism of turbidity removal
[7, 8].

 Corresponding author

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

Other studies have focused on quality of water treated by coagulation using two
forms of the seed (shelled and unshelled) as well as using water extract with model
turbid water (kaolin suspension) as the water source[8, 9].
Others have carried out investigations into the effect of extracting all the oil from
Moringa oleifera seed on its coagulation effectiveness using turbid river water as the
raw water source [10].
In the present study, varying quantities of oil 20% w/w, 25% w/w and 30% w/w
kernel weight was extracted from Moringa oleifera seed. The cake remaining after oil
extraction was dissolved in water and applied in coagulation of model turbid water
(kaolin suspension) and turbid river water samples to determine the percentage of oil
removed which gave the best coagulation efficiency.

2. MATERIALS AND METHODS

2.1 Model turbid water (kaolin suspension) samples

Five grams of kaolin, heavy grade (BDH Chemicals) was added to 500 ml distilled
water. 50 mg/L concentration of sodium carbonate solution was added to the kaolin
suspension and the total volume was made up to one liter. The suspension was stirred
slowly at 20 rpm for 30 minutes in a jar test apparatus for uniform dispersion and
allowed to stand for 24 hours for hydration of the clay particles [1].
This stock solution was used in the preparation of water with turbidity varying from
25 to 400 NTU by serial dilution. Turbidity was measured with Hach Turbidimeter
(Camlab model 2100 AN).

2.2 River water samples

River water samples were collected from the raw water inlet taps at two Water
Treatment Plants in Selangor State, Malaysia from River Batang Kali at Batang Kali
and River Selangor at Rantau Panjang Lama.

2.3 Moringa oleifera cake preparation

Dry Moringa oleifera seeds used in the studies were obtained from gardeners in
Serdang, Selangor, Malaysia. The seed wings and coat were removed from selected
dry good quality Moringa oleifera seeds and the nuts ground to a fine powder using a
food processor, National MJ-85CN. The dry mill attachment of the Food processor
was used for the preparation of the water extraction of Moringa oleifera powder after
oil extraction. Electro-thermal Soxhlet apparatus was used to extract oil from the
Moringa oleifera seeds powder using hexane as solvent at a temperature of 70°C.
Trial runs were initially carried out to determine the number of cycles required to
achieve the desired oil extracted. Twenty percent by weight of seed was the lowest oil
removable after one cycle of operation of the Soxhlet apparatus while 30% w/w of
seed was the maximum amount of oil removable from the seed samples used for the
studies. Samples of Moringa oleifera seed powder cake corresponding to three levels
of oil extracted viz. 20% w/w, 25% w/w and 30% w/w seed kernel weight
respectively referred to as S1, S2, S3 in Table 2 were used for the coagulation studies
in two stages. The flow diagram for the seed preparation is shown in Fig. 1.

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

Table 1: Characteristics of model turbid water (kaolin suspension) used in coagulation.

Parameter Range of values

Turbidity(NTU)

Low 25 - 45

Medium 50 - 100

High 150 - 400

pH 7.4 – 7.7

Zeta potential (millivolt) 0.8 – 2.16

Alkalinity( mg/L as CaCO3 ) 24 – 32

Table 1: Characteristics of model turbid water (kaolin suspension) used in coagulation

Parameter Range of values

Turbidity(NTU)

Low 25 - 45

Medium 50 - 100

High 150 - 400

pH 7.4 – 7.7

Zeta potential (millivolt) 0.8 – 2.16

Alkalinity( mg/L as CaCO3 ) 24 – 32

3. EXPERIMENTAL PROCEDURES

The coagulation studies were carried out in two stages. The first stage involved
application of the three levels of water extracted solution corresponding to S1 S2, S3
respectively to coagulate low, medium, and high turbidity model turbid water (kaolin
suspension). The characteristics of the model turbid water (kaolin suspension) and
river water samples viz. turbidity measured with a turbidimeter Hach model 21200P,
zeta potential with Zeta meter System 3.0+, pH with pH meter Cyberscan 2000 and
alkalinity using Standard Methods[11] are as presented in Tables 1 and 2.
The second stage of the investigation involved the application of the sample of
Moringa oleifera seed powder cake that achieved the best turbidity removal in
coagulation of model turbid water (kaolin suspension) to the river water samples.

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

Fig. 1: Schematic of processing of Moringa oleifera seeds used in coagulation studies.

3.1 Coagulation of model turbid water:

500 mL of water samples for each level of turbidity was put in each of six 600 mL
capacity beakers and placed under the Jar test apparatus (Jar Tester CZ 150). The
apparatus was set at rapid mixing speed of 125 rpm for 4 minutes and slow mixing
speed of 40 rpm for 25 minutes. Varying dosages of S1 S2, S3 solution extracted in
water was added to each beaker. A settling time of one hour was allowed after which
the residual turbidity of the clarified water samples from each beaker was measured
and recorded.

3.2 Coagulation of river water samples from River Batang Kali and River
Selangor

Based on the results obtained from the first stage of the studies, the Moringa oleifera
seed powder cake that gave the best turbidity removal was used in the coagulation
studies using the same operating physical parameters of rapid and slow mixing rates
and times. For Batang Kali River samples two levels of turbidity used were 32 and
502 NTU respectively while for River Selangor, 87 and 466 NTU were recorded
respectively.

Seed preparation: remove
wings, coat, shell, grind to

fine powder

Extraction of oil
using Soxhlet

distillation process

Residue cake: Water
extraction to be used as
coagulant (S1, S2, S3 )

Oil: Dried and stored
for other uses

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

4. RESULTS AND DISCUSSION

4.1 Raw water characteristics.

Model turbid water (kaolin suspension):

Table 1 shows the raw water characteristics of model turbid water. The pH varied
from 7.4 to 7.7 with the alkalinity varying from 24 to 32 mg/L. The zeta potential
varied from 0.8 to 2.16 millivolts. The raw water turbidity varied from 25 to 400
NTU.

4.2 Surface water quality.

Table 2 shows the raw water characteristics of river water samples from River Batang
Kali and River Selangor respectively. The pH and total alkalinity for the two raw
water samples were almost the same. The pH varied from 7 .4 to 8.0 implying slight
alkalinity with alkalinity varying from 24 to 32 mg/L and Zeta potential 0.90 to 1.40
millivolts for River Batang Kali water samples. For River Selangor water samples,
the pH varied from 7.1 to 7.3 implying almost neutral water with alkalinity varying
from 30 to 34 mg/L and Zeta potential of between 0.81 and 1.01 millivolts. The raw
water turbidity for River Batang Kali varied from 32 to 502 NTU while that of River
Selangor varied from 87 to 321 NTU respectively.

4.3 Coagulation of low turbidity model turbid water (kaolin suspension).

Figure 2 shows the results of coagulation studies on low turbidity model turbid water
with initial turbidity of 35 NTU using S1, S2, S3 with dosage varying from 10 to 30
mg/L. It was observed that for the three seed preparations increasing dosage resulted
in rapid decrease in residual turbidity up to 10 mg/L dosage when the residual
turbidity started to increase gradually until the dosage reached 30 mg/L. The gradual
increase was probably due to over dosage that led to restabilization of the destabilized
suspended solids, which had agglomerated into flocs. More significantly it was
observed that the best turbidity removal was that from S2 with residual turbidity of
2.9 NTU corresponding to 91.7% turbidity removal.

4.4 Coagulation of medium turbidity model turbid water (kaolin suspension).

Figure 3 shows the results of coagulation studies on medium turbidity model turbid
water with initial turbidity of 100 NTU using S1, S2, S3. For S3 with dosage varying
from 50 to 100 mg/L, it was observed that from a rapid reduction in residual turbidity
to 12 NTU at 50 mg/L., increasing dosage resulted in increasing residual turbidity'
implying restabilization of destabilized flocs during the coagulation process. For S2
the residual turbidity was observed to decrease gradually to 7 NTU at 50 mg/L
dosage and 4.5 NTU at 100 mg/L. Similarly for S1 there was gradual decrease in
residual turbidity with increasing dosage with a final lowest residual turbidity of 20
NTU at 100 mg/L. S2 again gave the best performance in turbidity removal
corresponding to 95.5 % turbidity removal.

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

0 10 20 30 40

Moringa oleifera dosage (mg/L)

R
es

id
ua

l T
ur

bi
di

dt
y(

N
TU

)

S1 S2

Fig. 2: Coagulation of model turbid water (kaolin suspension) with initial turbidity of
35 NTU using Moringa oleifera seed extract

100

120

0 20 40 60 80 100 120

Moringa oleifera dosage(mg/L)

R
es

id
ua

l t
ur

bi
di

ty
(N

TU
)

S1 S2 S3

Fig. 3: Coagulation of model turbid water (kaolin suspension) with initial turbidity of
100 NTU using Moringa oleifera seed extract.

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

4.5 Coagulation of high turbidity model turbid water (kaolin suspension).

Figure 4 shows the results of coagulation studies oil high turbidity model turbid water
with initial turbidity of 300 NTU using Moringa oleifera seed cake with S1, S2, S3
respectively. The Moringa oleifera dosage applied was varied from 100 to 200 mg/L.
For S3, the lowest level of residual turbidity of 9 NTU was recorded at a dosage of
100 mg/L after which there was a gradual increase of residual turbidity with
increasing dosage. However for S2 and S1, residual turbidity continued to decrease
with increasing dosage with lowest residual turbidity observed at 150 mg/1, of 6
NTU and 3 NTU respectively after which there was gradual increase in residual
turbidity for all the three seed preparations until the test run was terminated. The
gradual increase was probably due to over dosing which led to restabilization of tile
destabilized suspended solids which had agglomerated into flocs. More significantly
it was observed that the best turbidity removal was that from S2 with residual
turbidity of 3 NTU corresponding to 99 % turbidity removal.

100

150

200

250

300

0 50 100 150 200 250

Moringa oleifera dosage(mg/L)

R
es

id
ua

l t
ur

bi
di

ty
(N

TU
) S1 S2 S3

Fig. 4: Coagulation of model turbid water (kaolin suspension) with initial turbidity of
300 NTU using Moringa oleifera seed extract.

4.6 Coagulation of water sample from Rivers Batang Kali and Selangor

Since sample S2 gave the best coagulation results with the model turbid water, it was
selected for use in turbidity removal from the turbid river water samples. Figure 5
shows the results of coagulation of water samples from River Batang Kali with initial
turbidity of 32 NTU and 502 NTU respectively.
For raw water sample with initial turbidity of 32 NTU, application of dosages of S2
from 10 to 30 mg/L caused initial decrease in residual turbidity to a lowest value of
10 NTU increasing to 27 NTU and finally decreasing to 21 NTU at 30 mg/L dosage.
For water sample with initial turbidity of 502 NTU with dosages varying from 100 to
250 mg/L, the residual turbidity decreased sharply to 5 NTU at 150 mg/L dosage

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

after which there was an increase to 14 NTU at 200 mg/L followed by a gradual
decrease again to a lowest value of 4 NTU at 250 mg/L dosage.
Results of coagulation of water samples from River Selangor with initial turbidity of
87 and 466 NTU respectively are shown in Fig. 6. For water sample with initial
turbidity of 87 NTU, application of dosages of S2 varying from 50 to 200 mg/L,
showed decreasing residual turbidity with increasing dosage to a lowest value of 5
NTU at 150 mg/L after which it increased again to 8 NTU at 200 mg/L. Similar
studies in which the raw water sample from River Selangor with initial turbidity of 66
NTU gave residual turbidity of 6.3 NTU on treating with Moringa oleifera seed
extract with no oil extracted at 250 mg/L dosage while for 35 % w/w kernel weight
oil extracted the residual turbidity was 6 NTU at 200 mg/L Moringa oleifera dosage [
10 ].
For water sample with initial turbidity of 466 NTU, there was rapid decrease in
residual turbidity to a lowest value of 5 NTU at 250 mg/L dosage after which there
was gradual increase (due to restabilization) in residual turbidity to 12 NTU at 300
mg/L dosage.
In the present study in which 25 % w/w kernel weight oil was extracted ( S2 ), it was
observed that not only was the residual turbidity achieved lower than in the previous
studies [ 3, 5, 6, 7, 9] but also importantly the dosage at which this was achieved was
much lower at 150 mg/L in contrast to 250 mg/L for no oil extracted and 200 mg/1,
for 35 % kernel weight oil extracted.
Similarly for raw water samples with high initial turbidity of 321 NTU application of
shelled blended Moringa oleifera with no oil extracted gave a residual turbidity of 9.9
NTU (96.9 %) at the economic dosage of 250 mg/L whilst the shelled oil extracted
Moringa oleifera out performed it by achieving a residual turbidity of 6.6 NTU (97.9
% turbidity removal.) [ 10 ]. The present study achieved residual turbidity level of 7
NTU at 250 mg/L, dosage using 25 % kernel weight oil extracted( S2 ) which was
better than that achieved in previous studies in which 35 % kernel weight oil was
extracted [ 10 ]..

100

200

300

400

500

600

0 50 100 150 200 250 300

Moringa oleifera dosage (mg/L)

R
es

id
ua

l t
u

rb
id

it
y(

N
TU

)

initial turbidity : 32 NTU

initial turbidity: 502 NTU

Fig. 5: Coagulation of turbid water from River Batang Kali using Moringa oleifera
seed extract (S2).

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

100

150

200

250

300

350

400

450

500

0 50 100 150 200 250 300 350

Moringa oleifera dosage (mg/L)

R
es

id
u

al
tu

rb
id

it
y

(N
TU

)
initial turbidity 87 NTU

initial turbidity 466 NTU

Fig. 6: Coagulation of turbid water from River Selangor using Moringa oleifera seed

extract (S2).

The present study involved the use of only jar tests in which only
coagulation/flocculation and settling processes were employed. It is therefore
recommended that investigations be carried out through pilot plant studies that will
involve the application of all unit operations and processes employed in conventional
water treatment of surface water for potable use.
From the results of pilot plant studies, guidelines required for full-scale application of
Moringa oleifera as a primary coagulant for turbidity removal may be developed.

5. SUMMARY OF FINDINGS/CONCLUSIONS

1. For model turbid water (kaolin suspension) coagulation of low turbidity (35
NTU), medium turbidity (100 NTU) and high turbidity (300 NTU) using
Moringa oleifera seeds extract with 20% w/w, 25% w/w and 30% w/w (S1, S2,
and S3 ) kernel weight of oil extracted respectively, 25 % oil extracted ( S2 )
gave the best turbidity removal.

2. Application of Moringa oleifera seeds extract with 25% w/w kernel weight oil
extracted ( S2 ) to River Batang Kali with low initial turbidity (32 NTU) and
high initial turbidity (502 NTU) gave a highest turbidity removal of 69 % and
99 % respectively.

3. Application of Moringa oleifera seed extract with 25 % kernel oil extracted( S2 )
to River Selangor with medium initial turbidity (87 NTU) and high initial
turbidity (466 NTU) gave a highest residual turbidity of 94 % and 98.9 %
respectively.

IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

4. Turbidity removal was found to increase with increase in initial turbidity during
coagulation of model turbid water (kaolin suspension) and river water samples.

ACKNOWLEDGEMENTS

The Malaysian Ministry of Science Technology and Environment (MOSTE) kindly
provided funding for the research through the "Intensification of Research in Priority
Areas" (IRPA) PROJECT NO 09-02-04-00.

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[3] S. A. Muyibi, “ Moringa oleifera seeds in water treatment”. Journal Institution of
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[7] S. A. Muyibi and L. M. Evison, “Coagulation of Turbid Water and Softening of Hard
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[8] A. Ndabigengesere, K. B. Narasiah, K. Subraimanian “Quality of water treated by
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[9] S. A. Muyibi, H. Hazalizah, I, Irmayanti, J. M. M. N. Megat “Coagulation of river
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[10] S. A. Muyibi, J. M. M. N, Megat, H. N. Lam, K . L. Tan “Effects of oil extraction from
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[11] American Public Health Association (APHA), American Water Works Association
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IIUM Engineering Journal, Vol. 4, No. 1, 2003 S. A. Muyibi et al.

Biographies