Abstract
The quality and accessibility of drinking water are of paramount importance to human health.
Drinking water may contain disease causing agents and toxic chemicals and to control the risks
to public health, systematic water quality monitoring and surveillance are required. Thousands
of chemicals have been identified in drinking water supplies around the world and are
considered potentially hazardous to human health at relatively high concentrations. Heavy
metals are the most harmful of the chemical pollutants and are of particular concern due to their
toxicities to humans. Moringa oleifera seed acts as a natural coagulant, adsorbent and
antimicrobial agent while commercial activated carbon is known for its excellent heavy metal
removal. It is believed that Moringa oleifera seed is an organic natural polymer. The
coagulation mechanism of the Moringa oleifera coagulant protein has been described as
adsorption, charge neutralization and interparticle bridging. It is mainly chara
1.0 INTRODUCTION
Potable water accessibility has always been a major problem encountered in the developing
countries (Eman et al., 2009; Yarahmadi et al., 2009; Kawo and Daneji, 2011; Mohammed et
al., 2013). Many have encountered diseases, sicknesses, stunted growth, deformity, death, etc.
from the consumption of bad water (whether from raw or treated sources) (Olowoyo and
Garuba, 2012). The fact is, some of the claimed treated water are even worse than the untreated
ones because of the poor method or excessive chemicals used.
Many people believe that any ground water (such as well and bore hole) which is well managed
without treatment is very good for consumption. But the case is different some times, because
some of these ground waters are located where there had been earlier deposition of toxic
materials (such as refuse, waste batteries, industrial waste, faeces, urine, dead animals, etc.).
However, while transferring the water from the depth, to the receiving end (i.e. storage), there
is tendency of it getting contaminated by microorganisms. Water below pH of 6.0 tend to attack
and dissolves heavy metals from its cache hence, depending on the type of cache (metal,
concrete or polymer made storage).
With water covering more than two-thirds of the Earth’s surface, it is hard to imagine that
potable water is a scarce resource. The problem is that less than 1% of the water on the planet
is readily available for drinking or agriculture. Most of the water on Earth (97%), is salt water
stored in the oceans; only 3% is freshwater. Of all of the freshwater on Earth, 68% is locked
up in the icecaps of Antarctica and Greenland, 30% is in the ground, and only 0.3% is contained
in surface waters such as lakes and rivers (Shakhashiri, 2011). Over one billion people lack
access to safe drinking water worldwide (Shakhashiri, 2011) and water-related disease
mortality ranges from 2.2 to 5 million annually (Peter, 2002). This death is as a result of wide
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range of water problems facing nations and individuals around the world. These problems
include international and regional disputes over water, water scarcity and contamination,
unsustainable use of groundwater, ecological degradation, and the threat of climate change
(Peter, 2002).
The contamination of water is largely as a result of turbidity, presence of dangerous microbes
(micro-organisms) and presence of excess and unwanted heavy metals. Turbidity which is the
amount of particulate matter present in water occurs in surface water majorly as a result of
intake of large water which usually come from rain fall, discharge from industries and houses,
rivers and streams etc. Turbidity also occurs in ground water (well) when flood flows in or
enters through an opening in the ground. Also, the presence of microbes (such as E. coli,
Samonella Enterica, Klebsiella, etc.) which are accumulated through exposure to the
atmosphere. Surface water bodies and some ground water are always exposed to the
atmosphere and organisms do move with air. Other ways of accumulating microbes are
contaminations from humans, animals, agricultural wastes, and discharges from various
sources.
Heavy metals get to both surface and ground water bodies through industrial activities (such
as paints and pigments, glass production, metal plating, and battery manufacturing process),
mining operations (Olowoyo and Garuba, 2012; Bernard et al., 2013). Heavy metals are
present in the soil, natural water and air in various forms. Some of them are constituents of
herbicides, pesticides, and fertilizers applications (Olowoyo and Garuba, 2012). Heavy metals
such as lead (Pb), chromium (Cr), copper (Cu), mercury (Hg), uranium (U), selenium (Se), zinc
(Zn), arsenic (As), cadmium (Cd), cobalt (Co), nickel (Ni) etc. are very toxic and are emitted
into water through the stated processes in quantities that expose human health to risks (Bernard
et al., 2013). Heavy metals are natural components of the earth crust (Chimezie et al., 2011),
and are not biodegradable (Bernard et al., 2013). These metals enter into living organisms
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through food or proximity to emission sources. They tend to bioaccumulate and are stored
faster than excreted. Industrial exposure accounts for a common route of contact in adults and
ingestion for children (Chimezie et al., 2011). This bioaccumulation leads to several health
problems in animal and human being such as cancer, kidney failure, metabolic acidosis, oral
ulcer, renal failure and damage (Bernard et al., 2013).
Potable water essentiality to lives cannot be over emphasised as it is a basic requirement for
living creatures and human being specifically. Water from all sources must have some form of
purification before consumption and various methods used in making water safe for consumer
depend on the character or nature of the water (Eman et al., 2009).
The objectives of treating water are basically to remove particulate matters (turbidity),
disinfection, and removal of excess and unwanted heavy metals. Hence every method that has
been employed in water treatment is just to achieve these objectives. Ultra-violet ray, reverse
osmosis, alum, chlorine, nontoxic organic acid, neutralizing chemicals, ion exchange,
filtration, aeration, ozone etc. have been the common methods used in water treatment. Some
of these methods are very expensive as they require high maintenance, skilled labour, capital,
energy, etc. also, the chemicals used are imported thereby raising its scarcity as it takes a longer
time to get them to the country and at a cost. Likewise, accumulation of chemicals such as
chlorine, alum, lime, etc. are very injurious to health hence those that take in treated waters
through these chemicals are prone to health hazards. Hence, nontoxic natural occurring
products are better for the treatment of water.
Products from natural sources like agricultural products (like Moringa, palm kernel shell etc.),
are good to be used in place of the chemicals used. This is because of their low cost, availability
and low or no negative health effect.
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Moringa oleifera is one of the most wide spread plant species that grows quickly at low
altitudes in the whole tropical belt, including arid zones. It can grow on medium soils having
relatively low humidity. Moringa Oleifera seeds are organic natural polymer (Eman et al.,
2009). Moringa oleifera tree is known as clarifier tree around the Nile River. This is the species
belonging to the north of India which is the most famous one among all species. This tree is
resistant to dryness and grows in arid and semiarid areas, so it is called miracle tree. One type
of this tree, i.e. Moringa Pergenia, belongs to Iran and grows in the deserts of Sistan-andBalochestan. (Yarahmadi et al., 2009).
Compared to the commonly used coagulant chemicals, Moringa oleifera has a number of
advantages which include low cost production of biodegradable sludge, lower sludge volume
(Nwaiwu et al., 2011), it is readily available, requires low or no skilled labour, environmental
friendly, low cost equipment, low maintenance, doesn’t release toxic materials into the treated
water, bears antimicrobial properties against S. typhi, V. cholerae and E. coli and it could be a
promising natural antimicrobial agent with potential application in controlling bacteria that
cause water borne diseases. And the most advantageous effect over chemical coagulants is the
stability of the pH during the coagulation and flocculation process (Mohammed et al., 2013).
The unwanted heavy metals could be eliminated via adsorption using activated carbon from
agricultural material. Adsorption is a surface phenomenon that occurs when a gas or liquid
solute accumulate on the surface of a solid or liquid forming a molecular or atomic film,
adsorption has been described as an effective separation process for treating industrial and
domestic effluents (Okeola and Odebunmi, 2010). It is widely used as effective physical
method of separation in order to eliminate or lower the concentration of a wide range of
dissolved pollutants (organics or inorganics) in the effluent. It is also known that adsorption is
one of the most efficient methods for the removal of heavy metals from wastewater (Kumar
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and Chinnaiya, 2009; Babatunde et al., 2009; Olowoyo and Garuba, 2012; Onundi et al.,
2010).
Activated carbon is the most widely used adsorbent due to its excellent adsorption capability
for heavy metals (Emmanuel et al., 2012). Activated carbon is an industrial raw material
obtained by carbonization of carbonaceous biomass materials within a temperature range of
300 to 600°C in the absence of oxygen. It aims at removing most volatiles leaving behind
carbon rich char whose surface area is larger than the original substance. Activated carbon can
be produced in different ways such as steam (heat) activation and acid activation (Okoroigwe
et al., 2013).
The advantages in using activated carbon in the treatment of water is as follows. It is readily
available, it requires low or no skilled labour, environmental friendly, requires low
maintenance, and lastly, application of activated carbon as an adsorbent offers highly effective
technological means in dealing with pollution of heavy metals and solving agricultural waste
disposal problems, with minimum investment required (Onundi et al., 2010). Therefore, this
research is focused on the treatment of water from Afe Babalola University Ado Ekiti
(ABUAD) bore hole using Moringa Oleifera and commercial activated carbon.
1.1 Research Problem
Production of drinkable water has increasingly become a major concern as the population
increases and the available sources for drinkable water remain the same. Maintenance and
increment of production of potable water is however very expensive.
Imported chemicals for treatment of water is expensive and have been shown to have harmful
effects on human health with prolonged consumption. Also the conventional methods and
technologies for the treatment of water used are way expensive. Studies have therefore showed
that agricultural products and by-products can be used for the treatment of water. Moringa
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oleifera is readily available in Nigeria. Although there have been several researches in recent
years on utilization of Moringa Oleifera for environmental and health purposes, there is
however need for its further utilization in water treatment.
There is also, a dearth of information on the utilization of both Moringa Oleifera and activated
carbon for the treatment of water.
1.2 Aim and Objectives
The aim of this research is to study the effectiveness of Moringa oleifera seed as a disinfectant
and adsorbent and activated carbon as an adsorbent to provide alternatives to treatment of water
from ABUAD bore hole. The objectives of this work are:
1. Characterization of water sample in order to determine its physicochemical properties.
2. Study of the disinfectant potential / performance of Moringa oleifera seed.
3. Study of the adsorption potential /performance of the commercial activated carbon.
4. Investigation of the effect disinfectant dosage on the disinfection capacity.
5. Investigation of the effect of adsorbent dosage on the adsorption capacity.
6. Characterization of final water sample in order to determine its physicochemical
properties and comparing it with the standard.
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1.3 Research Scope and Limitation
1. Moringa oleifera seed capacity will be investigated and evaluated.
2. The adsorption capacity of the activated carbon will be investigated and evaluated.
3. Investigation of the effects of parameters (such as adsorbent dosage, contact time and
initial concentration) on the disinfection and adsorption processes will be carried out
according to standard.
4. The scope of this research is limited to water sourced from ABUAD bore hole (located
around ABUAD water plant), Moringa from ABUAD farm (ABUAD Moringa plant)
and commercial activated carbon from a local vendor.
5. The limitation of the work is anchored on analytical tools locally available within the
university (ABUAD).
1.3 Justification
The adverse effects of Water impurities on human health has drawn the attention of researchers
to alternative ways of removing impurities such as heavy metals that are very injurious to
health. Though some heavy metals are required in trace amount, while some are not even
needed at all. Also, microbes present in the water body also have negative impact on humans
and animals. Government and non-governmental bodies have tried many methods to ensure
that potable water is produced so as to put the community in safety, but the expenses of the
conventional methods have frustrated their efforts, thereby forcing them to either produce bad
water, small quantity of water supply or even total shut down of their processes. Hence, the
production of water using a cost effective method is stealing the show of research today.
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Therefore, the success of this research will create and encourage a very cost effective and more
efficient water treatment process using Moringa oleifera seed and commercial activated carbon
compared to the expensive, energy consuming, man power consuming, and health hazardous
conventional water treatment process