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Options for economically controlling the menace of water hyacinth in the Niger Delta of
Nigeria.
1
J. A. Akankali, *E. I. Elenwo2
1. Department of Fisheries, Faculty of Agriculture, University of Port Harcourt, Choba,
Nigeria
2. Department of Geography and Environmental Management, Faculty of Social Science,
University of Port Harcourt, Choba, Nigeria.
*Corresponding Author„s Email: [email protected].
Abstract
Economically controlling aquatic weeds is the most realistic way of ensuring the sustainable
eradication of the weed from water bodies. This is particularly true of the Niger Delta region where
the need to utilize the weed as a source of raw material for producing other goods is needed.
Furthermore this will serve as a means of ensuring that the region is economically empowering her
inhabitants by making sure that the aquatic environment is devoid of the nuisance of the weed. This
study reviewed some of the methods and also practically experimented on the use of the weed as an
ingredient for animal feed. The nutrient profile of the weed was also analyzed to determine its
proximate nutritional value as a basis for developing a comparison with other conventional animal
feed production ingredients. The use of water hyacinth as a source of biogas for energy production
was reviewed and analyzed as a potential means of power generation in the Niger Delta region.
Other uses such as water pollution control were equally reviewed. Based on the findings;
recommendations were made as to how best some of these economic based method of controlling
the environmental menace of water hyacinth in the Niger Delta region could be properly harnessed
for the best interest of the inhabitants of the region and the nation at large.
Key-Words: Options, Economically, Controlling, Menace, Water-Hyacinth.
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Introduction
Potentials of water hyacinth as an economic product
Water hyacinth is generally considered a nuisance weed. Consequently, its challenges and problems seem
to undermine its perceived benefits. However through research, the water hyacinth has been proven to be a
viable raw material for local economy capable of generating significant economic ventures in localities
and regions where they occur all over the world, (Nagendra and Goppal , 2001). Consequently, this aspect
of this research will highlight the real and potential economic uses which water hyacinth can be utilized. It
is hoped that such information will be of immense benefit in creating local economic ventures that will
empower the community people of the Niger Delta region. On the other hand the aquatic environments of
the Niger Delta region will become sanitized of the menace and nuisance impacts of the weed. Thus,
utilizing water hyacinth economically shall definitely result in a win-win situation for the region. In this
research, several methods of economically utilizing water hyacinth have been identified. Among these are
its use for production of energy through anaerobic digestion, as feed stock for pork meat production,
organic manure, briquetting and production of furniture‟s among others.
Proposal for Utilization of Water Hyacinth for Power Generation in the Niger Delta.
The biomass waste of water hyacinth has the potential to be utilized for energy or power generation.
Anaerobic digestion (AD) offers a very attractive route to utilize certain categories of biomass for meeting
partial energy needs. AD can successfully treat the organic fraction of biomass (Mailu, 2001). AD is the
controlled degradation of biodegradable waste in absence of oxygen and presence of different consortia of
bacteria that catalyze series of complex microbial reactions3. The process is one of the most promising for
biomass wastes as it provides a source of energy while simultaneously resolving ecological and
agrochemical issues. Water hyacinth has attracted the attention of scientists to use it as a potential biomass
as it is rich in nitrogen, essential nutrients and has a high content of fermentable matter. Apart from
biogas, the sludge from the biogas process contains almost all of the plant required nutrients and can be
used as a good fertilizer with no detrimental effects on the environment. Mailu (2001) and Pieterse and
Murphy (2010) reported a study which blended water hyacinth with sludge as a means of energy
production. The summary of the experiment was reported as follows:
“Water hyacinth (WH) and primary sludge (PS) from wastewater treatment plants can be used to generate
energy which could save on the fossil fuels conventionally used as source of energy. In this study, the
possibility was explored to mix water hyacinth with primary sludge in different combinations for
anaerobic co-digestion, so that energy can be generated as biogas and at the same time digested sludge
can be used as fertilizer for agricultural applications. Co-digestion of water hyacinth and primary sludge
with required amount of water (W) was carried out in 250 ml batch digesters. Pretreatment of water
hyacinth was done by Alkali method. Anaerobic co-digestion was carried out in mesophilic temperature
range (30°C to 37°C) with different fermentation slurries of 8% total solids (TS). Co-digestion was
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carried for a retention period of 60 days. The gas produced was collected by the downward displacement
of water, and was subsequently measured and analyzed. Fermentation slurry PS3 (mixing ratio of 4:
26.14: 69.86 for WH: PS: W) was found to be optimum, which gave the highest biogas yield of 0.35 l/gVS
(unit for measuring biogas yield per volume of biomass used in an AD digestion facility) with composition
69.6 % CH4, 25.8% CO2, 0.8 % N2 and 3.8 % O2. The overall results showed that blending water
hyacinth with primary sludge had significant improvement on the biogas yield”.Plates 4.2a shows the
experimental set up, while figure 4.2b and tables 4.2a to 4.2d clearly show that biogas production from
water hyacinth blended with primary sludge that has an immense biogas yielding capacity (Pieterse and
Murphy, 2010: 67-68).
Figure 4.2a: Schematic illustration of AD processes (Pieterse and Murphy, 2010)
Benefits of Anaerobic Digestion Facilities
The biogas is used in a combined heat and power plant or cleansed of carbon dioxide and injected
into the National Grid. A by-product of the AD process is digestate; a stable, nutrient-rich substance
that is most commonly used as a renewable fertilizer or a soil conditioner. There are enormous
benefits that will accrue to the Niger Deltans by adopting Anaerobic Digestion as part of their
overall water hyacinth control and utilization management strategy. Essentially the three areas that
this can have tremendous positive impact in our society are:
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1) Commercial benefits of anaerobic digestion.
2) Environmental benefits of anaerobic digestion
3) Renewable energy benefits of anaerobic digestion.
The proposed AD strategy of environmental waste management offers a simple cost effective waste
management solution to an environmental and commercial challenge, (Mailu, 2001).
1) Commercial benefits of anaerobic digestion
 AD sites are chosen from a logistical standpoint in order for a network of local producers to
be matched to one plant, offering certainty, lower costs and carbon reduction.
 Source-segregating of organic waste, and having it collected, saves on Landfill costs,
transportation costs and reduces methane and carbon dioxide emissions.
 AD enhances organization‟s brand and green credentials
 Utilizes feedstock supplies from suppliers on long-term partnerships and contracts thereby
creating a sustained economic activity chain.
 AD plant construction and operation provides local jobs and the creation of new
technological skill-sets.
2) Environmental benefits of anaerobic digestion –
 AD will be a contributing factor towards the Nigerian renewable energy targets
 Valuable nutrients are recycled back into the land through the production of digestate
 Digestate may also be used as a feedstock for ethanol production and for low-grade building
materials.
 AD shall provide „green‟ jobs and contributes to growth in the realization of a „green‟
economy Nigeria
 Local government Councils shall be saving significant sums by turning to segregated waste
collection, freeing much-needed resources to schools, hospitals and infrastructure
 By increasing awareness of the food waste we throw away (over 7m tonnes domestically
and a further 12m tonnes by the commercial and industrial food industry), householders will
buy less, and therefore waste less.
3) Renewable energy benefits of anaerobic digestion
 The most significant advantage AD has over other alternative energy sources is that it
delivers base load electricity locally (the energy consumed for day-to-day by home
operation that isn‟t used in response to external weather conditions such as heating and
cooling)

AD plants can be constructed and commissioned typically within 12 months, paying
particular attention to health and safety regulation and best practices.
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


This means with an accelerated commitment as being envisaged for the Nigerian pilot
plants, the delivery time can be significantly reduced.
AD plants have a low visual impact on the environment
The nature of AD projects makes it inherent for a close and sympathetic liaison with local
government, residents groups, business and landowners and additional stakeholders on all
issues and concerns regarding AD and its impact on the local community (Mailu, 2001).
Water Hyacinth as Renewable Energy
Renewable Energy can be defined as “Energy sources that do not deplete the earth‟s natural
resources and do not create added waste products.”
The Renewable Energy sector can be segmented into three sub-areas. These are:
 Elemental: Where energy is generated from the elements, namely solar, wind, hydro and
geothermal
 Biomass: Where agricultural crops, wood (forestry) or other organics (e.g. algae) are grown
specifically as inputs to a renewable energy processes
 Biomass (Energy from Waste): Where waste from commercial, industrial, domestic and
agricultural sources can be converted into renewable energy
 Anaerobic Digestion fits within the Biomass sector and is classed as Energy from Waste
(EfW) technology and other organics which of course include water hyacinth. In Nigeria for
example, where the current energy (power) supply is grossly inadequate in comparison to
the demands by population, the value chain of the energy derivative of adopting the
anaerobic digestion system in managing water hyacinth will add to the Country‟s inefficient
energy (power) requirements solution and this assertion can never ever be over emphasized.
Anaerobic Digestion progress in the United Kingdom: Lessons for Nigeria.
It is important to draw lessons from other developed economies as regards AD policies and
projects, so that Nigerian government can be inspired to start something similar. Hence, the UK
scenario of AD development is chronicled as follows; the United Kingdom government has focused
on mitigating climate change and her over-reliance on fossil fuels and expensive energy imports.
The re-use of organic waste material coupled with technological advancements is in line with the
Government‟s 2010 commitment to „introduce measures to promote a huge increase in energy from
waste through anaerobic digestion‟ (Pieterse and Murphy, 2010). By 2020, biological material sent
to landfill sites must be at 35% of the levels recorded in 1995. By 2014, producers of
biodegradable and organic waste face the possibility of their landfill tax (a tax on the disposal of
waste to landfill sites) rising to £80 per tonne (up from £40 per tonne in 2009). Government
ambition is to move towards a Zero Waste Economy. Not an economy where no waste is produced,
rather an economy where all resources are fully valued and there is currently a shortfall in residual
waste treatment facilities, such as anaerobic digestion plants.Note that in the Nigeria of today,
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where we are aiming to be one the world‟s largest economy by 2020, the availability of specialized
residual waste treatment facility such as AD can be said to be almost nonexistent. This calls for
emergency response to be declared in our waste management system.
Legislative and Environmental incentive to encourage AD development in the United Kingdom.
 The EU Renewable Energy Directive has set the UK a target of generating 15% of its energy
from renewables by 2020. This challenging and binding target has resulted in a range of
economic incentives that is driving up returns for renewable energy providers.
 The EU Landfill Directive requires the UK to dramatically reduce the amount of waste that goes
to landfill. The introduction of a Landfill tax (currently £48 per tonne) and the Landfill
Allowance Trading Scheme has boosted incentives for infrastructure and processes that provide
alternatives to landfill.
The UK Government is making a strong commitment to the UK renewable energy sector like other
large World economies and has articulated a keen interest in developing Anaerobic Digestion in
particular. Nigeria‟s aspiration to be in the league of the globes largest economy by 2020 should
therefore, as a matter of necessity, begin to adopt similar measures as AD technology in managing her
wastes. Reason is increased growth invariably leads to an increased waste stream and volume over time
(Pieterse and Murphy (2010).
Proposed Strategy for Harnessing Water Hyacinth AD Potentials in the Niger Delta
The preceding information on the use of water hyacinth for biogas production stands it out as the most
realistic means through which water hyacinth can be utilized economically. Apart from being a source
of cheap and clean renewable energy for communities in the region, it is also a very good source of
organic fertilizer. The digestate from the process is a rich source of Nitrogen and other essential
nutrients for crop production. The AD process plants will also create employment in the rural
communities, while simultaneously keeping the Niger Delta aquatic region free from the nuisance and
other environmental challenges that is associated with water hyacinth infestation. This technology and
method of controlling water hyacinth in the region is therefore highly recommended for urgent
implementation by the NDDC, adopting the strategies already outlined in this regard. Adopting at least
four units of Community/ Cooperatives / Clusters of Local Government Authority model based pilot
AD plant projects, will be a good way to kick start this initiative in the Niger Delta region.
From table 4.4a, the various benefits that varying capacities of AD plants can produce are illustrated as
already practiced in the UK.
Integrated Control Method of Water Hyacinth
Integrated Water Hyacinth Control Programme was introduced to form a holistic approach to use the
various control options that were available: combining physical, chemical and biological control
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methods and use it as an economic resource. An integrated control method of controlling water
hyacinth (Eichhorniacrassipes) involves the integration of mechanical, chemical and biological
methods because of the inadequacies of each method. Achmad (2011) developed a practical integrated
water hyacinth control system based on a pathogen, Cercosporarodmanii; arthropods, including
Neochetinaeichhorniae; a moth, Sameodesalbiguttalis and a mite, Orthogalumnaterebrantis and 2
chemical herbicides; 2, 4-D and diquat. He reported that the pathogen or the arthropods alone did not
completely control water hyacinth, but that their combination was highly synergistic, yielding 99%
control after 7 months. Frequently, two or more recommended methods of weed prevention or control
used together will provide more effective results at a lower cost than any of the methods used alone.
Table 4.4a: Facts of some AD Plants in the UK
Plant location
Capacity
of
Organic waste
utilized
1) Westwood
Processes
Bedford
Road, 65,000 tonnes
Rushden,
of food waste
Northamptonshire each year
Wattage
electricity
of Equivalent
homes
power met
Producing 2.9
Sufficient
MW
of to power
renewable
over 6000
electricity
homes
Quantity
of Status of Plant
Biofertlizer /
Acreage covered
A
nutrient
rich Operational
Biofertlizer enough
to support 1,750
acres of growing
crop
2) Milton Parc, Processes
Generates 1.8
Sufficient
produces
33,000 Operational
Milton
Ernest, 47,000 tonnes MW of green to power tonnes of a nutrient
Bedfordshire
of
food electricity
over 3000
rich bio-fertilizer
waste per year
homes
3)LlwynIsaf,
Processes
0.5MW
Enough for Produces
8,000 Operational
ClynnogFawr,
11,500 tonnes of green
700 houses tonnes of a nutrient
Caernarfon,
of food waste electricity
annually
rich bio-fertilizer
Gwynedd
per year
generating
Holywell Road, The plant will will
Enough to To produces about Under
Rhuallt, St Asaph process 22,500 produce 1MW
power
10,000 tonnes of a construction tonnes of food of renewable 1500
nutrient
rich bio- due
for
waste per year
electricity
homes
fertilizer
completion
July 2014
(Pieterse and Murphy, (2010)
An integrated control method of controlling water hyacinth (Eichhorniacrassipes) involves the
combination of a water drawdown and a herbicide application on exposed submerged-type vegetation
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followed by a refilling and introduction of grass carp at a low stocking density controlled the serious
pond weed problem and prevent its reoccurrence (Wersterdahl &Sculthorpe, 1998). Integrated control is
a sensible strategy that includes the combination of mechanical, biological and chemical methods that
complement each other. The first step is to make certain that the weevils are established on the
infestation, and then carry out mechanical control or a spray program using a selective herbicide.
Selectively controlling strips of the water hyacinth mats helps concentrate the biological control insects
onto the remaining weed to increase damage and mechanical removal of dead plants will avoid water
quality degradation by masses of rotting weed, (Gibbons &Godfrey, 2000). In the light of the foregoing
discussion, we propose that an integrated, long term programme must include the followings:
1.
An integrated control method of controlling water hyacinth (Eichhorniacrassipes) involves the
integration of mechanical, chemical and biological methods
2.
The construction of facilities to effectively utilize the water hyacinth brought ashore by
mechanical removal and these include:

Biogas plants, with the provision for heating, lighting and the generation of electricity.

Composting units, and distribution to neighbouring farms.

Units to produce animal feed.

The production of dried water hyacinth stems, and their distribution to individuals and
small businesses making crafts or furniture.

Paper manufacture.
3.
Government support from the three tiers (local, state and Federal)
to villagers and small
businesses that wish to use water hyacinth and this can also be in the form of:
o Training workshops for community development workers, agricultural extension workers
and villagers in water hyacinth utilization and "conservation farming".
o Technical advice with regard to all aspects of water hyacinth utilization
o Advice to small businesses.
o The availability of grants and loans for the purchase of basic equipment.
Economic Utilization of water hyacinth through Other Sundry Methods
One of the most important components of the integrated water hyacinth control strategy is the processing
of the harvested water hyacinth into various economic products as the positive potential uses of the weed
seem to outweigh its negative attributes. Prior research on water hyacinth‟s effects on water quality has
focused mainly on the consequences of the dense mats formed by the interlocking of individual plants.
Water hyacinth harvests have been put into valuable uses in several countries and the methods of
converting the plant material into valuable products have emerged. Apart from its ornamental value, the
plant has been found useful as a source of animal feed (Gopal, 1997). It is also a source of fertilizers;
biomass energy; raw materials for building, handcraft making and paper production as reported by
(Oyakawa & Griffiths, 1996). In addition the plant has been found to be useful as a filter worth of solving
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man created problems of pollution in water bodies. Some of the positive attributes of water hyacinth that
make it suitable as an economic plant are:
a.
It is abundantly available.
b.
It grows readily without any need for sowing, weeding or fertilising.
c.
It does not require any land space.
d.
to harvest it is to do an environmental favour
e.
Grows vigorously and abundantly to produce a large biomass.
f.
Has leaves rich in protein, being as valuable as that in potatoes or clover.
g.
Has a high potassium concentration.
h.
Has tough, fibrous roots that purify water, by absorbing the nitrogen and phosphorus on which it
thrives, and also many other substances that pollute fresh water, including minerals. It absorbs also
toxic chemicals such as lead and mercury.
Although water hyacinth is seen in many countries as a weed and is responsible for many of the
problems outlined above, many individuals, groups and institutions have been able to turn the
problem around and find useful applications for the plant. The plant itself, though more than 95%
water, has a fibrous tissue and a high energy and protein content, and can be used for a variety of
useful applications (Ogutu-Ohwayo&Ajuonu,1996). Below are a number of possible uses for the
plant, some which have been developed and
others still in their infancy or remain as ideas only.
Treatments of Sewage Effluent and Tannery
Water hyacinth can be used to aid the process of water purification either for drinking water or for liquid
effluent from sewage systems. In a drinking water treatment plant water hyacinth has been used as part of
the pre-treatment purification step. Clean, healthy plants have been incorporated into water clarifiers and
help with the removal of small flocs that remain after initial coagulation and flocs removal or settling,
(Haider,1989). The result is a significant decrease in turbidity due to the removal of flocs and also slight
reduction in organic matter in the water. In sewage systems, the root structures of water hyacinth (and
other aquatic plants) provide a suitable environment for aerobic bacteria to function. Aerobic bacteria
feed on nutrients and produce inorganic compounds which in turn provide food for the plants. The plants
grow quickly and can be harvested to provide rich and valuable compost. Water hyacinth has also been
used for the removal or reduction of heavy metals, organic compounds and pathogens from water,
(Gopal, 1997).Water hyacinth can be used in purifying sewage effluent - as a wastewater effluent
treatment filter. Grodowitz (1998) reported that an acre of the plant could remove 2.4 tons of ammonium
sulphate (nitrogen fertilizers) in one hour. He also reported that the plant is a good de-pollutant capable of
removing toxic heavy metal pollutants e.g. mercury and lead. He reported that in the city of San Diego,
USA, water hyacinth was used to remove heavy metals. It is an efficient low cost water purifier. He also
reported that it has been used as a wastewater effluent treatment filter e.g. tannery wastes in India and
rubber processing plants in Malaysia. On many occasions it has been demonstrated that this weed is
excellent water depollutant for domestic water wastes. In studies where the ability of the water hyacinth
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to remove lead, cadmium, and mercury was tested, the plant removed approximately 65 per cent of lead,
50 per cent of cadmium, and 65 per cent of mercury from water polluted with 10 ppm of lead and 1 ppm
of mercury and cadmium, (Wolverton& McDonald, 2008), One hectare of water hyacinth plants is
potentially capable of removing 160 kg of phenol per 72 hectares from water polluted with this chemical.
Combinations of microorganisms with water hyacinths must be seriously considered in developing
filtration systems for removing toxic trace chemicals, such as heavy metals and carcinogenic materials
(Wolverton and McDonald, 2008).
Conclusion
The results of several studies show that plants such as the water hyacinth use appreciable amounts of the
inorganic forms of nitrogen and phosphorus found in domestic sewage. In so doing, they effect a
significant reduction in the concentration of materials that are major contributors to the inorganic nutrient
enrichment of natural waters,Wooten and Dodd (2007). Water hyacinth has long been used commercially
for cleaning wastewater. The luxuriant plant‟s tremendous capacity for absorbing nutrients and other
pollutants from wastewater has long been overlooked by many wastewater engineers. Water hyacinth is
also known for its ability to grow in severe polluted waters. Eichhorniacrassipesis well studied as an
aquatic plant that can improve effluent quality from oxidation ponds and as a main component of one
integrated advanced system for treatment of municipal, agricultural and industrial wastewaters (USEPA,
1988). In recent years, a greater interest has been shown for research of aquatic macrophytes as good
candidates for pollutant removal or even as bio - indicators for heavy metals in aquatic ecosystems.
Water hyacinth is one of the aquatic plants species successfully used for wastewater treatment in decades,
as Eichhorniacrassipeshas a huge potential for removal of the vast range of pollutants from wastewater
(USEPA, 1988).
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