GROUNDWATER QUALITY: A CASE STUDY OF AMUWO ODOFIN LOCAL GOVERNMENT AREA BY AKWARA NOREDIA 000402032 Being a project submitted to The department of Civil and Environmental Engineering Faculty of Engineering University of Lagos In partial fulfilment of Requirements for the award of the degree
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GROUNDWATER QUALITY:
A CASE STUDY OF AMUWO ODOFIN LOCAL
GOVERNMENT AREA
BY
AKWARA NOREDIA
000402032
Being a project submitted to
The department of Civil and Environmental Engineering
Faculty of Engineering
University of Lagos
In partial fulfilment of Requirements for the award of the degree
of Bachelor of Science in Civil Engineering
September 2006
TABLE OF CONTENTS
Certification
Dedication
Acknowledgements
Abstract
CHAPTER ONE: Introduction
1.0 Introduction
1.1 Background to the Study
1.2. Description of case study area
1.3. Importance of the Project
CHAPTER TWO: Literature Review
2.1 Groundwater
2.2 Groundwater quality from deep wells
2.3 Groundwater contamination
2.3.1 Domestic/Municipal sources of groundwater
contaminants
2.4 Effect of Urban Development on groundwater
- 2.4.1 Relationship between Municipal landfills and
Groundwater pollution
2.5 Water supply system in Amuwo Odofin LGA
2.6 Saltwater intrusion in deltaic terrains
2.6 Water quality standards
2.7 The geology of the case study area
- 2.7.1 Hydrogeology
CHAPTER THREE: Methodology
3.1 Methodology
- 3.1.1. Meetings with the local government officers
- 3.1.2. Survey carried out in case study area
- 3.1.3. Field Investigation
3.2 Sources of Data
3.3 Parameters
3.4 Field Study
3.5 Laboratory Analysis
CHAPTER FOUR: Discussion of Results
4.1 Descriptions of Location
4.2 Discussion of Physio-chemical parameters
4.3 Discussion of results
4.4. Groundwater Remediation
-4.4.1 Programs of activities for Groundwater Remediation
-4.4.2 Groundwater remediation from Point sources
CHAPTER FIVE: Conclusion and Recommendation
5.1 Conclusion
5.2 Protection/Prevention of Groundwater pollution
5.3 Recommendation
REFERENCES
APPENDICES
CERTIFICATION
This is to certify that this project “GROUNDWATER QUALITY AND
REMEDIATION OF GROUNDWATER POLLUTION: A CASE STUDY OF
AMUWO ODOFIN LOCAL GOVERNMENT AREA” was carried out by
AKWARA NOREDIA and supervised by DR. E.O LONGE
Student: AKWARA NOREDIA
Signature:…………………………….
Date:………………………………….
Supervisor: DR. E.O. LONGE Head of Department: PROF. SALAU
Signature:…………………... Signature……………………………
Date:………………………… Date:…………………………………
DEDICATION
This project is dedicated to the Loving Father, in whom I repose all trust.
And to the memory of Emmanuel O. Akwara
ACKNOWLEDGEMENT
To the Akwara family. Thanks for the support you gave me.
ABSTRACT
Groundwater pollution is a growing problem in most countries.
CHAPTER ONE:
INTRODUCTION
1.1 Background to the Study
The quality of water available to a community is closely related to the health
issues of the community. An important factor in the growth of a community is
its accessibility to potable water. In many countries of the world including
Nigeria, groundwater constitutes the main source of drinking water. But in
recent decades, the groundwater quality has very much deteriorated due to rapid
industrialization and human mismanagement. The sources of water in Lagos
state are from surface water and groundwater. Since 1910 to date, the main
concern of the authorities managing water supply to Lagos has always been
how to increase the supply of potable water due to the ever increasing
population of Lagos as a commercial nerve centre of the nation's economy. The
population of Lagos is growing rapidly daily with more people settling down
than moving out and the effect of this large scale growth is felt on the
environment. At present, Lagos has a population of about 15 million.
In the past, surface water was the main source of water supply for domestic and
industrial use. Awareness of the large store of the water underground led to the
implementation of water supply units based totally on groundwater.
Groundwater is of major importance to civilization; because it is the largest
reserve of drinkable water in regions where humans can live. Now, water
resources in Lagos state for domestic, industrial and commercial uses, are
becoming scarce as a result of pollution of water bodies by wastewater, which
contains inorganic compounds, bacteria, etc. The effects of on-lot sewage
disposal systems in densely populated areas surface runoff from developed
areas, industrial site contamination are some of the problems facing
groundwater quality in Lagos state.
In Amuwo Odofin and Festac, the population housing is divided into three
types:
o Blocks of three bedroom family units (flats)
o Semi-detachable houses
o Fully-detached houses and privately built homes
Most of the households depend on dug wells and boreholes for their
water supply. The problem lies in ensuring that the community gets clean,
potable water. Pollution can cause problems with the taste, odour and colour in
water. Many of the chemicals that enter the water with runoff and seepage are,
even in minute amounts, toxic to human health and can alter ecosystems by
destroying fish, wildlife and plants. Heavy metals, pesticides, chlorinated
hydrocarbons are typical examples.
The majority of the community wells and boreholes are provided for by the
Pollutants can be divided into chemical, physical and microbiological
pollutants. Chemical pollutants can be divided into non-persistent (degradable)
and persistent (pollutants which degrade slowly). Persistent pollution is the
most rapidly growing type of pollution and includes substances that degrade
very slowly or cannot be broken down at all; they may remain in the aquatic
environment for years or longer periods of time.
Persistent pollutants include some pesticides (e.g. DDT, dieldrin), some
leachate components from landfill sites, petroleum and petroleum products,
PCBs, dioxins, polyaromatic hydrocarbons (PAHs), radionuclides, metals such
as lead, mercury, and cadmium. The damage they cause is either irreversible or
reparable only over decades or centuries.
Non persistent pollutants include domestic sewage, fertilisers and some
industrial wastes. These compounds can be broken down by chemical reactions
or by natural bacteria into simple, non-polluting substances such as carbon
dioxide and nitrogen. However if the pollution load is high, this development
can lead to low oxygen levels; fortunately this damage can be reversible.
Table 1: List of possible groundwater pollutants and pollution
indicators
Total dissolved solids
C O D ( chemical oxygen
demand)
B O D ( biological oxygen
demand)
Carbon (organically linked)
Hydrogen (organically linked)
Nitrogen
Detergents
Phenols
Oxygen
Sulphates (SO2-4)
H2S
Nitrates (NO3-)
Nitrites (NO2)
Ammonium (NH4)
Arsenic
SiO2
Conductivity
Free CO2
Bicarbonates (HCO3)
Iron (Fe2+ And Fe3+)
Manganese
Sodium
Potassium
Calcium
Magnesium
Total Hardness
Chloride
Fluoride
Phosphate (HPO4)
Zinc
Lead
Copper
Temperature
pH
Redox potential
(Source: Fried, 1987)
2.3.1. Domestic/Municipal sources of Groundwater contaminants
Anthropogenic activities have been established as having impacts on ground
water. The most likely sources of groundwater contamination in the case study
area are from domestic/ municipal wastes and natural mineralization processes.
From information gathered through testing by private water purification and
supply companies in the local government area, it has been observed that the
groundwater has these impurities:
- a high iron (Fe2+ and Fe3+ ions) content
- Pathogenic organisms like Shigella (bacteria), Giardia lamblia (protozoa)
and Cryptosporidium.
- Indicators and indicator organisms like Escherichia coli (E. coli)
- A moderately acidic pH number, varying in areas from 6.1 to 6.8
- An degree of salinity present in the water
Exact values of these have not been determined. After tests carried out during
the course of this study, more pollutants and impurities will be added to these
and their precise amounts in the groundwater of the study area will be
determined. Certain pollutants like Volatile Organic Compounds (VOCs) are
not commonly found in non-industrial areas.
Festac town was designed with a central sewer system, but the efficiency of this
has depreciated with age and lack of maintenance and as a result, septic tanks
are the main form of domestic sewage treatment in the case study area. In other
parts of Amuwo Odofin LGA, septic tanks are the only form of domestic
sewage treatment. This scenario has led to the presence of faecal coliforms and
higher microbial loads in the surface waters and groundwater of the area. In
rainy seasons, starting from midway March to September, with the heavy rains
usually experienced in the area, cases of the septic tanks of private homes
overflowing has been known. There is a landfill located in 7 th avenue and this
is a point source of groundwater contamination.
Where the subsurface geology permits rapid downward movement of water
from the surface, or where the ground water sources are tapped near the surface,
aquifers may be vulnerable to pollution. Shallow dug wells, or drilled wells in
which the well casing is not properly grouted (sealed), are particularly
susceptible to contamination.
2.4. Effect of Urban Development on Groundwater
With urban development comes increased dependence on groundwater and
more amounts of water being consumed daily. Lagos state’s per capita demand
is listed as 120 to 150l.c.d. In areas where groundwater is the only source of
water, town development placed unfavourable changes in groundwater. Bujwid
(1981) presented a paper which stated that these changes usually found
expression in the increase of some nitrogen compounds, trace elements and
bacteriological contamination.
In Amuwo Odofin LGA, while precise values of population have not been
ascertained, it is generally held that the amenities planned for by the housing
authorities are inadequate for the use of the current inhabitants. Over-population
is a known problem. With the increase in the population, and lack of
governmental forecast, several private wells and boreholes were sunk.
Currently, the local government is not aware of how many exist in the area.
Privately owned homes have either a well or borehole each, while the flats
make use of a minimum of two (2) wells and three boreholes. More boreholes
are being constructed monthly as more people move into the area.
It has become difficult to also control solid waste disposal in the area. Private
sector participation has come in to undertake this task, as the internal squabbles
between the state and federal government as to under whose jurisdiction Festac
town fell under had affected the release of funds in the past.
2.4.1. Relationship between Municipal landfills and groundwater pollution
A sanitary landfill is a method of solid waste disposal that should function
without creating a nuisance or hazard to public health or to the environment.
Landfills can also be classified as hazardous (toxic) or as municipal by the types
of waste accepted. Over the last 30 years a number of problems have been
recognized at landfill sites, including contamination of nearby surface waters
and underlying groundwater by landfill leachates. Municipal landfills have
impacted groundwater resources especially hydro-geological environments
where impacts are expected to be greatest, for example where the water table is
shallow, where groundwater is of good quality and flow is rapid.
2.5 Water Supply system in Amuwo Odofin LGA
Festac town was constructed in 1977-78. It was a planned urban development
by the federal government of Nigeria. For the first ten (10) years of its
existence, water was supplied to its inhabitants by the state water board.
Amuwo Odofin LGA is still on the water grid. Of recent, the local government
has erratic supply of water. Though Amuwo Odofin LGA is bordered by water
bodies (the canal), it is generally assumed that the surface water is very
polluted; consequently, groundwater is preferred and many residents have
decided to get their water supply from privately constructed shallow wells and
boreholes. “The definition of shallow or deep water well will vary with the
hydro geological conditions considered to be the standard with the area”
(Clarke, 1996). For this project, Shallow wells refer to water wells not more
than 70m deep, which must be completed with steel casings and screens
(Obiora and Onwuka, 2005). The type of wells constructed in Festac and
Amuwo Odofin are of the Hand dugs variety and these are “more vulnerable to
pollution than a drilled borehole” (Clarke, 1996). The wells in Festac town
range from depths of 4m to 8m, while wells in Amuwo Odofin go as down
90m. Boreholes in the area are of almost the same depth as wells (some are
drilled deeper to reach a cleaner source of water). The wells are of concrete ring
type, with a natural layer of sand at the bottom. Wells generally improve with
age, although they need to be maintained and checked annually for breaks in the
casing that might lead to contamination of the water well.
2.5. Saltwater Intrusion in Deltaic terrains
Saltwater intrusion is defined as the introduction, accumulation, or formation of
saline water in a water of lesser salinity. It is one of the most common problems
in coastal aquifers, i.e. the induced flow of salt water into fresh water aquifers
caused by groundwater development. The intrusion of seawater into coastal
aquifers is a widespread phenomenon that increasingly causes the problem of
groundwater salinity. In places where groundwater is being pumped from
aquifers that are in hydraulic connection with the sea, the induced gradients
may cause the migration of salt-water from the sea toward the well. The key to
controlling this problem is to maintain the proper balance between water being
pumped from the aquifer and the amount of water recharging it. Constant
monitoring of the salt-water interface is necessary in determining proper control
measures.
The increased use of groundwater causes the salt-water interface to move inland
and closer to the ground surface. In the past, many communities coming across
salt-water intrusion problems simply set up new production wells further inland.
This only complicated the problem. Saltwater intrusion refers to surface water
contamination while saltwater encroachment refers to the contamination of
ground water. The processes involved in these intrusions can result from natural
phenomena or human-influenced activities, particularly dredging, and may
assume a variety of specific forms. The concern about saltwater intrusion arises
from the environmental damage or water use impairment that may result
because of the presence of salts in ground or surface waters. Excessive salt
concentrations can render water unfit for consumption by humans and animals
as well as impair the growth of plants. Agricultural and industrial uses of water
can also be impaired by high salinity levels. When no freshwater is available,
slightly saline waters may be viewed as having acceptable quality for some
purposes.
There are a number of possible effects of saltwater contamination, as indicated
by the following:
- Enhancement of the toxicity of other toxic chemicals dissolved in water may occur.
- Saturation levels of dissolved oxygen decrease with increasing salinity,
thus potentially accentuating poor dissolved oxygen conditions in
streams.
- Permeability of soils being altered, thus altering aquifer recharge
conditions.
- Large costs may be incurred in the treatment of saline water in order to
make it usable.
- Increasing salinity may force the use of alternate sources of water which,
in turn, may have adverse consequences.
Exhaustive urban, industrial and agricultural activity relies heavily on
exploitation of groundwater resources, and in recent years, this reliance has led
to increasing levels of salinity in groundwater systems. There has been a
reported case of saltwater intrusion in Festac in recent years, but it was not well
documented.
2.6. Water quality standards
Water quality standards vary according to each country, with the WHO setting
the international standards for water quality. According to Cohn et al, these
standards stretch from aesthetic quality (taste, odour, turbidity, hardness and
colour) to Health aspects (ranging from disease agents to organic and inorganic
contaminants).
Table 2: WHO Standards for quality of water
Physical WHO standard
P E Turbidity (ppm)ColourTaste and Odour
5 25 5 50 Unobjectionable
Chemical
pH 7-8.5 < 6.5 or> 9.2
Total Solids (mg/l) 500 1500
Total Hardness (as CaCO3) (mg/l)
-- --
Calcium (as Ca) (mg/l) 75 200
Magnesium (mg/l) 50 150
Iron (as Fe) (mg/l) 0.3 1.0
Manganese (mg/l) 0.1 0.5
Copper (as Cu) (mg/l) 1.0 1.5
Zinc (mg/l) 5.0 15.0
Chlorides (as Cl) (mg/l) 200 600
Sulphate (as SO4) (mg/l) 200 400
Phenolic substances 0.001 0.002
(mg/l)
Fluorides (mg/l) 0.5 1.0 to 1.5
Nitrates (mg/l) -- 50 to 100
Arsenic -- 0.2
Lead -- 0.1
Cyanides -- 0.01
Radio-activity (as Alfa
Emmitter (µc/ml)
-- 10-9
Bacteriological
Five 10ml portions Not more than 10% of all portions examined shall show presence of coliform bacteria. MPN≤ 1 per 100ml. No two consecutive samples shall have the presence of coliform bacteria
P= Permissible E= Excessive
Source: J.P. Sanjaygadhvi
Table 3: Federal Ministry of the Environment, Nigeria: Standards for