Purification of Turbid Water with Pisum Sativum Seeds and ... - IJGHC

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International Journal of Green and Herbal Chemistry
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Green Chemistry
IJGHC; September-November, 2012; Vol.1.No.3, 296-301.
Research Article
Purification of Turbid Water with Pisum Sativum
Seeds and Solar Energy
M.Nurul Hassan 1 , S.Vivek 2 and Syeda Azeem Unnisa* 3
1
Biotechnologist, Centennial College, Toronto, Canada,
Faculty, IPE, Osmania University Campus, Hyderabad 500007, A.P,India.
3* Research Officer, Regional Centre for Urban and Environmental Studies, Osmania
University, Hyderabad, 500007, A.P, India.
Received: 20 September 2012; Revised: 19 October 2012; Accepted: 20 October 2012.
Abstract: This paper reports on an investigation into the potential of
indigenous or natural water treatment methods as alternatives to
conventional chemical water treatment methods. The seeds of Pysum
sativum natural plant species was evaluated for the removal of turbidity,
and their efficiency were compared with that of alum. The use of a solar
energy-saving method to disinfect drinking water was evaluated. The
study revealed that for raw water with turbidity of 20, 40, 80 NTU,
coagulation with seed extract from natural plant species reduced natural
turbidity by 85, 81.25 and 74.35 percent when the seed extract was used
as the primary coagulant. Leaving samples of water clarified by natural
coagulants on a black-painted roof for 6 hours achieved up to 100 percent
bacteria kill in summer season.
Keywords: Pysum sativum, turbid water, natural coagulant, solar disinfection,
bacteria,
INTRODUCTION
Provision of clean and safe water in rural areas is a great challenge for the developing countries of the
world since most communities rely on poor traditional sources that often provide unsafe domestic water 1 .
It is estimated that world over, about three million people die annually from water-borne diseases 2 . This
situation is a source of great concern and makes water purification at the household level especially
desirable and important. The reliance of the majority of the population on polluted water supply sources
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M.Nurul Hassan et al.
poses a great risk to health 3 . These sources are heavily polluted by animal excretions, human excreta, and
sewage effluents. Fecal pollution of water supplies is attributed to poor disposal of excreta and a low
standard of community hygiene. Conventional water treatment relies on the addition of chemicals such as
alum (aluminum sulfate) as coagulants and the addition of chlorine as a bactericide 4 . The availability of
these chemicals, which depends on foreign exchange, is unreliable and unpredictable. Because of
economic and political constraints, the universal provision of piped water is not currently feasible 5 . This
circumstance leaves millions without access to safe drinking water. Interim solutions are clearly needed.
The purpose of our study was to evaluate the potential of traditional treatment methods (i.e., those based
on local knowledge inherited from previous generations). The study used plant materials (seeds) of Pysum
sativum plant for turbidity removal and used sterilization of water by solar energy for destruction of
bacteria, and compared the results with those of standard treatment practices.
MATERIALS AND METHODS
Model turbid water: A stock of synthetic turbid water samples was prepared by suspending 10g of
Kaolin in 1L of tap water. The suspension was stirred for 30 minutes and left to stand for 24hrs to hydrate
particles. The desire turbidity of 20 NTU (low), 40 NTU (medium) and 80 NTU (high) was prepared by
mixing a fraction of decanted kaolin suspension with tap water. The pH of synthetic water samples was
maintained constant at 7.0. E.coli was mixed in stock turbid water from preserve lab culture samples.
Natural coagulant preparation: Seeds were collected from nearby market. Dissections of the seed pods
were performed by hand: The seeds were removed from the pods and were dried in the hot sun. Fine
powder was made by using mortar and pestle and was stored in air tighten packets for future use. The
scientific names and coagulating active agent is presented in Table 1.
Table -1: Scientific names and active component in agro based seeds
Scientific Name Seeds Photo Active Agent
Pysum sativum
Albumin proteins and starch
Solar exposure time: Poly Ethylene Terephtalate (PET) bottles made of transparent, clear plastic,
cylinder shape with a surface area of 23 × 7.2 × 6.0 cm was used for experimental purpose as they are
good transmitters of light in the UV and visible range of the solar spectrum. The total exposure time of
experiments varied from 1 to 6 hours.
Analytical measurements: Turbidity was measured using a calibrated ELICO CL 52D Turbidity meter to
measure the turbidity of the solution in Nephelometric Turbidity Units (NTU). pH , temperature and
alkalinity was measured by physico-chemical methods.
Microbial analysis: Microbial analysis was done by standard methods. The Escherichia coli counts were
enumerated on eosin methylene blue after 0.1 milliliters of the turbid water samples was aseptically serial
diluted up to three fold. Samples were analyzed before and after treatment for its potability using 6,7
method. The colonies are enumerated by using digital colony meter and the log reduction is given by the
following formula.
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M.Nurul Hassan et al.
No. Of colonies formed
1
Cfu/ml =
Sample plated
X
Dilution factor
EXPERIMENTAL
Experimental works evaluate the efficiency and the coagulation effect of the coagulant extract from
Pysum sativum based seeds by using jar test method for summer and rainy seasons -2009. Coagulation
tests were conducted with jar-test equipment, which has a base floc illuminator. Flash mixing time (at 100
rpm) was 1 minute and flocculation time (at 40 rpm) was 15 minutes. The samples were then allowed to
settle for various intervals of time, after which the water samples were examined for physical and
chemical quality parameters and the lowest dose of coagulant that gave satisfactory turbidity reduction of
the water was established. Physical and chemical parameters of raw and clarified water — pH and
alkalinity were determined according to standard methods. Turbidity was determined by the
Nephelometric method with a turbidity meter. Plastic 1,000-mL bottles were filled to the 1,000-mL mark
with water clarified by natural coagulants, and the lids were put on. The bottles were then put on a blackpainted
roof, where they stayed for different periods of time, after which the water samples were
examined for microbial numbers according to the standard plate count method.
RESULTS AND DISCUSSION
Results of the treated samples from natural coagulant Pysum sativum and solar disinfection are shown in
Figure 1, 2.1, 2.2, 2.3 and 3.1, 3.2, 3.3. Jar test method for natural coagulant (Pysum sativum) showed
high turbidity reduction and high coagulant activity in samples treated as it contain active ingredient
starch, which is non-ionic polymer which forms positive and negative ions in water and the mechanisms
of coagulation is by bridging. For summer season an optimum dose of 0.2 g/l of this coagulant resulted in
85, 81.25 percent with 60 minute settling time for 20 and 40 NTU and 75.35 percent in 120 minute for 80
NTU. Further clarified water with Pysum sativum was exposed to sunlight which showed 100 percent
inactivation of both E.coli and Coliforms counts within one hour, with no subsequent reactivation of
growth after 24 hours in treated water sample when compared to control. Whereas, in rainy season an
optimum dose of 0.2 g/l of this coagulant resulted in 83.75, 78 percent with 60 minute settling time for 20
and 40 NTU and 73 percent in 120 minute for 80 NTU. Further clarified water with Pysum sativum was
exposed to sunlight which showed less percent inactivation of both E.coli and Coliforms counts within
three hour of exposure with subsequent reactivation of growth after 24 hours in control and treated water
samples. Pysum sativum seeds resulted in producing treated water with turbidity more than 5 NTU as per
WHO guidelines. Therefore either they can be used as primary coagulant (or) coagulant aid in relation to
alum. pH was retained at 7.0 before and after treatment with natural coagulant and alum. Initial alkalinity
was found to be 230-300mg/l and decreased to 180-200 mg/l with treatment. These coagulants are from
agro based seeds if when mixed with the water does not release any constituents that are harmful to health
and no objectionable taste and odour nor increase in the concentration of TDS was observed.
Whereas water clarified with natural coagulant when exposed to solar disinfection in summer season
showed drastic inactivation of E.coli and Coliforms in treated sample when compared to rainy season.
The active agent is a water-soluble cationic protein that harbours very good coagulation properties which
is used in extremely low dosages than that used for crude seed extract 8 . Also, water treated by pure
proteins is not prone to bacterial re-growth. The researchers thus affirmed that, the isolation and
purification of active agents from the seed is relatively easy compared to laborious manipulation of other
proteins and thus recommended it for use in water treatment processes. Studies have shown that synergies
from the combined application of radiation and thermal treatment have a significant effect on the die-off
rate of micro organisms. Turbidity is a significant factor in the disinfection process. The effectiveness of
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M.Nurul Hassan et al.
solar disinfection has been tested on samples with turbidities ranging from less than 10 NTU to
approximately 300 NTU. Researchers have found that higher turbidity samples exposed to sunlight
attained consistently higher water temperatures, which was attributed to absorption of radiation by the
particulate matter 9 . More turbid samples, at 300 NTU, also had less inactivation of E.coli compared to
samples with little or no turbidity. This may be in part due shielding of organisms by particles 10 . Less than
1.6
Various turbidities removed by P ys um s ativum and alum
1.4
O p ti m u m D o s a g e (g /l )
1.2
1
0.8
0.6
0.4
0.2
20NTU
40NTU
80NTU
0
Alum
P eas
s ummer
P eas rainy
1 % of the total incident UV light is able to penetrate beyond a water depth of 2cm from the surface in
samples with turbidities greater than 200 NTU 11 . Therefore, it may be necessary to filter turbid waters
before sun exposure.
Fig.1: Treatment of turbid water by natural coagulant – summer season
20NT U
40NT U
80NT U
25
C o l o n i e s p e r 1 0 0 M L
20
15
10
5
0
B .T A .T S .D
E .coli
C oliforms
40
35
C o l o n i e s p e r 1 0 0 m l
30
25
20
15
10
5
0
B .T A.T S .D
E .coli
C oliforms
50
C o l o n i e s p e r 1 0 0 m l
40
30
20
10
0
B .T A.T S .D
E .coli
C oliforms
Fig.2.1. Fig.2.2. Fig.2.3.
Fig. 2.1, 2.2, and 2.3: Inactivation of bacteria in 1 hr by solar disinfection from water clarified with
Pysum sativum for various turbidities –summer season
BT – Before treatment, AT- After treatment, SD- solar disinfection
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M.Nurul Hassan et al.
20NTU
40NT U
80NT U
30
35
35
25
C o l o n i e s p e r m l
20
15
10
5
E .c oli
C oliforms
30
C o l o n i e s p e r m l
25
20
15
10
5
E .c oli
C oliforms
30
C o l o n i e s p e r m l
25
20
15
10
5
E .coli
C oliforms
0
B .T A.T S .D
0
B .T A.T S .D
0
B .T A.T S .D
Fig.3.1. Fig.3.2. Fig. 3.3.
Fig. 3.1, 3.2 and 3.3: Inactivation of bacteria in 3 hr by solar disinfection from water clarified
with Pysum sativum for various turbidities –rainy season
CONCLUSIONS
Studies have shown that the combination of natural treatment methods using plant seeds (Pysum sativum)
and solar disinfection indicate that this method can effectively clarify and disinfect household drinking
water, so the use of natural coagulants that are locally available in combination with solar radiation, which
is abundant and inexhaustible, provides a solution to the need for clean and safe drinking water in the
rural communities.
ACKNOWLEDGEMENTS
The authors thank the Department of Science Technology (DST) who has granted project under water
initiative technology, New Delhi.
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2. World Health Organisation, Water for Life: making it happens, Geneva: Switzerland, 2005.
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7. M. Cheesbrough, Medical laboratory manual for Tropical Health Technology, USA, 1984.
8. S.C.Kehoe,M.R. Barer,L.O. Devlin and K.G. Mcguigan,. Applied Microbiology 2004; 38: 410-
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9. M.Berney, H. Weilenmann, A. Simonetti and T. Egli , Journal of Applied Microbiology 2006:
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85: 293-295.
11. Syeda Azeem Unnisa, P.Deepthi and K.Mukkanti, Sciencia Acta Xaveriana 2010; 1: 1-13.
*Correspondence Author: Syeda Azeem Unnisa; Research Officer, Regional Centre for
Urban and Environmental Studies, Osmania University, Hyderabad, 500007, A.P, INDIA
E-mail:syeda_30@yahoo.co.in.
301 IJGHC; 2012, Vol.1, No.3, 296-301.