ABSTRACT
The present study was carried out to determine the prevalence of bacterial organisms isolated from biofilms of water system. Our results clearly demonstrated the overall prevalence raie of the microorganism was 100%. The frequency of occurrence of the bacterial isolates were; Staphylococcus 100%, Streptococcus 73.33%, Enterobacter 66.66%, E. coli 60% and Klebsiella 53.33%. The physiochemical analysis result obtained were all within the WHO standards for drinking water quality, the physiochemical parameters were within acceptable limits. The results were compared with WHO. The investigation shows that the boreholes water at male and female hostels met with WHO Standards for drinking water. Biofilms in drinking water distribution system could provide nutrients for microbial growth, bio systems and proliferation. It is necessary to treat water distribution plants and provide adequate public health education in order to safe guard human health and animal health especially in developing countries.
TABLE OF CONTENTS
Title i
Certification
ii
Dedication iii
Acknowledgement iv
Table
of contents v
List of
tables ix
List of
figure x
Abstract xi
CHAPTER ONE: INTRODUCTION
1.1 Background Studies 2
1.2 Aim 3
1.3 Objectives 3
1.4 Problem
Statement 3
CHAPTER TWO: LITERATURE REVIEW
2.1 Biofilm 4
2.2 Development of Biofilms 7
2.3 Environmental Factors Influencing Biofilm
Development 8
2.3.1 Effect of pH 8
2.3.2 Rheological and Adhesive Properties of
Biofilms 9
2.3.3 Effect of Temperature 9
2.4 Biofilms Formation 10
2.4.1 Factors Affecting Biofilms Formation 11
2.4.2 Substratum Effect 11
2.4.3 Conditioning Film 11
2.4.4 Hydrodynamics 12
2.4.5 Characteristics of Aqueous Medium 12
2.4.6 Horizontal Gene Transfer 12
2.4.7 Quorum Sensing 13
2.5 Biofilm Structure and Function 14
2.5.1 Extracellular Polymeric Substances 14
2.5.2 Protein 15
2.5.3 Interaction of Particles 16
2.6 Water 16
2.6.1 Sources of Water 17
2.6.1.1 Surface Water 17
2.6.1.2 Ground Water 17
2.6.1.3 Sources of Water Contamination 17
2.7 Bacteria That Can Be Found In Water 18
2.7.1 Escherichia
Coli 18
2.7.2 Staphylococcus
aureus 19
2.7.3 Klebsiella
Species 19
2.7.4 Streptococcus
Species 20
2.7.5 Enterobacter
Species 20
2.8 Physiochemical Quality of Water 21
2.8.1 Temperature 21
2.8.2 Total Dissolved Solids (TDS mg/c) 21
2.8.3 Hydrogen Ion Concentration 21
2.8.4 Alkalinity (Mg/V) 22
2.8.5 Total Hardness 22
2.8.6 Turbidity 22
2.8.7 Conductivity 22
2.8.8 Colour 23
2.8.9 Odour 23
2.9 Biofilms in Drinking Water Distribution
Systems 23
2.10 Effect of Long Storage of Water on Biofilm
Formation 24
CHAPTER
THREE: MATERIALS AND METHODS
3.1 Study Area 25
3.2 Collection of Samples 25
3.3 Preparation of Culture Media 25
3.4 Bacteria Inoculation and Isolation 26
3.5 Isolation of Biofilm Producing Bacteria 26
3.6 Determination of Biofilm Formation of
Isolates 27
3.7 Characterization and Identification of
Organisms 27
3.8 Gram Stain 27
3.9 Biochemical Tests 28
3.9.1 Catalase Test 28
3.9.2 Coagulase Test 28
3.9.3 Citrate Utilization Test 29
3.9.4 Urease Test 29
3.9.5 Indole Test 29
3.9.6 Oxidase Test 30
3.9.7 Methyl Red Test 30
3.9.8 Motility Test 30
3.9.9 Sugar Fermentation Test 31
3.10 Methods for the Physico-Chemical Analysis
of the Water 31
3.10.1 pH 31
3.10.2 Determination of Conductivity 31
3.10.3 Determination of Temperature 32
3.10.4 Determination of Turbidity 32
3.10.5 Determination of Dissolved Solids 32
3.10.6 Determination of Total Suspended Solids (TSS).
32
3.10.7 Determination of Chloride 33
3.10.8 Determination Dissolved Oxygen 33
3.10.9 Determination of Chemical Oxygen Demand 33
3.10.10
Determination of Nitrate 33
3.10.11
Determination of Phosphate 34
3.10.12
Determination of Sulphate 34
CHAPTER
FOUR: RESULTS
4.0 Results 35
CHAPTER
FIVE: DISCUSSION, CONCLUSION AND RECOMMENDATION
5.1 Discussion 42
5.2 Conclusion 43
5.3 Recommendation 44
REFERENCES 45
LIST OF TABLES
TABLE Title Page
1: Percentage Occurrence of
Bacteria Isolates 37
2: Conforming of Biofilm
Formation 38
3:
Identification
and Characterization of Bacteria Isolates 39
4: The Physio-chemical
Results of the Water Samples Analyzed. 40
LIST OF FIGURES
Figure Title
Page
I: Occurrence
of Biofilm Suspect On Slip Film Culture 41
CHAPTER ONE
1.0 INTRODUCTION
Drinking water is an important resource all-round the
globe (Martiny et al., 2003), but
water borne disease is still a major cause of death in many parts of the world
(Fawell and Nieuwenhuijsen, 2003). Nevertheless, little research has focused on
identifying the bacteria in water distribution systems (Martiny et al., 2003).
Microorganisms that grow in the environment may enter
the drinking water and attach to and grow on drinking water pipes and other
surfaces, forming biofilms (WHO, 2014) as the most common means of
non-pathogenic microorganisms of source water (Farkas et al., 2013), however, quite a few opportunistic bacterial
pathogens naturally occur in aquatic and soil environments are able to persist
and grow in biofilms of drinking water systems (Wingender and Flemming, 2011).
The
Contamination of drinking water by
Escherichia coli that only come from human and animal faecal waste (USEPA,
2009) is an important aspect of drinking water quality (WHO, 2011). Five
groups of Escherichia coli causing
diarrhoea in humans and other warm blooded animals have been identified (Brook
et al., 1994 and Wasteson, 2001), that include:
Enterotoxingenic Escherichia coli (ETEC)
Enteropathogenic Escherichia coli (EPEC)
Enteroaggregative Escherichia
coli (EAEC)
Enteroinvasive Escherichia
coli ( EIEC)
Enterohaemorrhagic Escherichia coli ( EHEC). The latter
includes shiga toxin (STX) producing Escherichia
coli (STX- EC) (Harake et al.,
2006).
Drinking water is essential to sustain life and a
satisfactory (adequate, safe and accessible) supply must be available to all
(WHO, 2004). The quality of life depends on the key elements such as the
quantity and the quality of water available for consumption. A rational use of
resources considering the support capacity of the ecosystems in which we live
indicates a sustainable society. Strategies such as management and protection
of water sources, effective treatment methods, the proper distribution and
handling of water are intended to be implemented worldwide.
Trend to increase productivity are evident in water
sectors as well as in food industry, in order to provide indispensable consumer
products for a continuously growing population, drinking water is not only a
liquid for hydration. It interacts with all industrial, agricultural, economic,
social and cultural components characterizing the human society (Ancuta, 2012).
Guidelines recommend monitoring of water in order to
characterize bacterial counts and identify organisms (Beale et al., 2013). The primary goal for this
monitoring is to identify the conditions that promote biofilm growth and
observe changes in bacterial trends. It is considered more important to
identify changes in the bacterial composition of the biofilm than to identify
increased bacterial numbers (Beale et al.,
2012).
1.1 Background Studies
Bacteria pathogens can form biofilms in water,
especially in different sources of drinking water which include boreholes,
streams, wells, storage (geepee) tanks, pots, bowls etc., when kept for a long
period of time. These pathogens could enter the water through the following
means; soil erosion, rain water fall, wind erosion, rock weathering, human
activities and so on. These pathogens have the potency to cause various
life-threatening infections.
Drinking water distribution systems have an intake of
suspended bacteria from different sources as such the bacteria present in
groundwater and raw surface waters which is not removed even after the
treatment, the bacteria yielding from the treatment processes such as bio
filters and or bacteria which is introduced by water is obstructed from other
aquatic environments. Many problems in drinking water distribution system
(DWDS) are microbial in nature, including biofilm growth, nitrification, microbial
mediated corrosion and the occurrence and persistence of pathogens (Regan et al., 2003; Beech and Sunner, 2004;
Emtiazi et al., 2004).
Microbial adhesion to surfaces and biofilm, formation
occur in environment on board ships (portable water systems, water treatment
facilities and air conditioning).
1.2 Aim
To analyse, the quality of water supply at both male
and female hostels.
1.3 Objectives
Ø To determine the various kinds of bacteria pathogens
that can be found in the water supply.
Ø To isolate the bacteria identify and characterize
them.
Ø To evaluate if the bacteria isolates are of public
health importance.
1.4 Problem Statement
The problems associated with the presence of biofilms
in drinking water sources are as follows.
1)
They may be
responsible for a wide range of water quality and operational problems.
2)
They can be
responsible for loss of distribution system disinfectant residuals, increased
bacterial levels, reduction of dissolved oxygen, taste and odour changes.
3)
Microbial
influenced corrosion, hydraulic roughness and reduced materials life.
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