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EVALUATION OF MICROBIOLOGICAL QUALITY OF WATER USING THE MEMBRANE FILTER TECHNIQUE

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

The quality of water is crucial for public health, as contaminated water can pose significant health risks. Various techniques are employed to assess water quality, among which the membrane filter technique stands out due to its effectiveness in identifying microbial contaminants. The atmosphere is the source of all water supplies. The rainfall of any region remains in part on the surface of the earth, the rest sink into the soil. According to Prescott et al (2011) the amount of ground water varies considerably from place to place and is obviously greater where the surface rock is porous such as time stone and chalk than it is area of non-porous or impermeable rock such as clay.

Underground water (well water) is stored water below ground, formed by rainfall It can be obtained by digging a hole through the earth surface until the water table is reached. It must be sunk to the depth of the permanent water table, if a constant water supply of water is to be obtained (Allen, 2004).

The water table falls during dry seasons but will not fall to dryness. And if it is deep enough, it reasons on the saturated zone. There are two types of well water, they are: the shallow surface well water and deep well water. Water from deep wells tends to be less polluted than that from surface shallow well (World Health Statistics, 1978).

Ground water are freed from much of their microbial flora by filtration through the soil and ordinarily have a lower bacterial content. But since ground waters can be polluted either from the surface or through fissures in the soil, a water supply must not be considered safe just because it is a ground water.

Ground water (well water) is used for several purposes such as washing, cooking, food processing and among others. Out of these used drinking of water seems to be the sensitive as it could have a directly deleterious impact on health of human beings. According to Allen (2004) water of adequate quantity and quality is essential for healthy life. The associations between sanitation, water and health are well known. Many diseases are associated with contaminated water and water shortage. Without adequate water, people can neither wash themselves properly nor their clothes nor their cooking utensils and food cannot be prepared adequately or hygienically. These restrictions on cleanliness result in various parasitic, fungal and skin disease, eye, infections and diarrhoeal disease.

Historically, water has played a significant role in the transmission of human diseases. Typhoid fever, cholera, infections, hepatitis, bacillary and amoebic dysenteries and many varieties of gastrointestinal diseases can all be transmitted by water. The introduction of water treatment with disinfection and the implementation of bacteriological surveillance programs to ensure the delivery of safe water have resulted in a dramatic decrease in the occurrence of water-related illness. The occasional occurrence of water born disease outbreaks, however, point out the continuity importance of strict supervision and control over the quality of public and private water supplies.

According to the Koronye and Ngoddy (2006) water is potable when it is colourless, odourless, tasteless and free from bacteria. A few substance like toxic chemical and microbes that are health hazards do occur in water, and can cause illness. From microbiological point of view, the pathogens most frequently transmitted through water are those, which can see infection of the intestinal tract, like dysentery, cholera, and typhoid fever.

According to Adeleke (20039), contamination by sewages or human excretion presents the greatest danger to public health associated with drinking water, and bacteriological testing continues to provide the most sensitive means of detecting of such pollution. Although modern microbiological techniques have made possible the detection of pathogenic bacteria, viruses, and protozoa in sewage and sewage effluents, it is not practical to attempt to isolate them as a routine procedure from samples of drinking water. He also stated that the pathogens present in water are usually outnumbered by normal intestinal bacteria, which are easier to isolate and identify. The presence of such organisms indicates that pathogens could be present; if they are absence, disease-producing organisms are probably also absent.

According to Slanetz and Bartley (2000), to ensure safe drinking water, government agencies must constantly examine water source for contamination disposal plants of urban areas must be checked to determine their levels of efficiency in removing microorganisms and toxic chemicals. Series of tests are used to determine the quality of water. When perform in a specific region under study, these tests are called sanitary survey.

Water free from harmful microorganisms and toxic chemicals is said to be potable. On the other hand, water containing either of these agents is said to be polluted and non-potable. It should be noticed that water free from odour and clear in appearance may still be contaminated with harmful microorganisms. Therefore, all water must be examined microbiologically.

Microbiological examination offers the most sensitive test for the detection of recent and potentially dangerous faced pollution, thereby providing a hygienic assessment of water quality with high sensitivity and specificity. For this reason. It is important to examine a drinking water source frequency by a single test rather than infrequently by a more complicated test or series of tests. It is ideal to look for individual specifically pathogen but it is not practical since. They are few in number than the non-pathogenic organisms and methods to  detect them are costly in the and money.

Prescott et al (2011) also stated that intestinal pathogen entering water via sewage usually are found they numbers because they die rapidly once they have left their host, and they enter the water only sporadically because the host is not always present. This creates a problem for the technologist who is trying to isolate them from a water sample. Many pathogens are also difficult to identify in a laboratory, and therefore, more time is required to so. For these reasons it is impractical to isolate pathogenic flora water sample, and a more rapid method of determining the presence of faecal materials was developed intestinal microorganisms that are normally present in faeces are used as an indicators of faecal pollution. Microorganisms such asEscherichia coli, Streptococcus faecalis (enterococcus), and Clostridium perfringens are used in various  countries of the world as indexes of faecal pollution.

Also prescott et al (2011)stated that large number of coliforms particularly Escherichia  coli, are numbers of constantly present in the faeces of humans and other warn-blooded animals. It follows that, if coliforms are present in water sample, then the sample must contain faecal material. If faecal material is present, the intestinal pathogens may also be present. Thus the presence of feacal coliform warns us that there may be intestinal pathogens present in the water sample.

The world Helath Organization (WHO, 1982) have standard for potable water of which coliform should be absent and total plate consist of bacterial growth should be 100CFU/m of water.

Adeleke (1976) also stated that microorganism associated with ground water are bacteria, protozoa and viruses. Communicable diseases which may be transmitted by bacteria include, typhoid fever, cholera, salmonellosis, bacillary dysentery etc. Viral diseases, transmitted include Hepatitis and poliomyelitis while protozoa such as Gardic and cryptosporidium can cause gastroenteritis and area very resistant to disinfectants. Certain fungi notable Aspergillus is a human pathogen while a born causes schistosomiasis, which may be transmitted through water. Other diseases including leptospirosis and Brucellosis may also be sometimes spread by water. All these diseases are said to be water-borne. Nevertheless, the possibility exists, and modern methods of water purification are designed to destroy virus as well as pathogenic bacteria.

It should be emphasized that no bacteriological analysis, of water can take the place of a complete knowledge of the conditions at the sources of supply and throughout a system. Contamination is often intermittent and may note be revealed by the examination of a single sample, the most a bacteriological report can prove is that, at the time of examination, bacteria indiscipline faecal pollution did not grow under laboratory conditions from a sample of water. Therefore, if a sanitary inspection shows that a well is subject to contamination or that water is inadequately treated or subject to contamination during storage considered unsafe irrespective of the results of bacteriological examination.

1.2 Statement of the Problem

Despite efforts to ensure clean water supply, microbial contamination remains a persistent concern in many water sources. The specific challenge lies in accurately assessing and monitoring the microbiological quality of water to prevent waterborne diseases.

1.3 Objectives of the Study

The main objective of this study is to determine the microbiological quality of water using the membrane filter technique. Specific objectives include:

i. To evaluate the impact of microbial contaminants on water quality.

ii. To determine the prevalence of specific microbial pathogens in water samples.

iii. To find out the effectiveness of the membrane filter technique in detecting microbial contaminants.

1.4 Research Questions

i. What is the impact of microbial contaminants on the overall quality of water?

ii. What is the prevalence rate of specific microbial pathogens in sampled water sources?

iii. How does the membrane filter technique compare to other methods in detecting microbial contaminants in water?

1.5 Significance of the Study

This study is significant as it contributes to understanding the microbial risks associated with water sources and validates the membrane filter technique as a reliable method for assessing water quality. Findings will inform policymakers, water quality managers, and public health officials in enhancing water safety measures.

1.6 Scope of the Study

This study focuses on evaluating the microbiological quality of water from selected sources using the membrane filter technique. It covers specific geographical areas and examines various water samples collected over a defined period.

1.7 Limitations of the Study

Limitations include constraints in sample size, geographical coverage, and potential variations in environmental conditions that may affect microbial counts. Interpretation of results is confined to the methods employed and may not encompass all possible microbial contaminants.

1.8 Definition of Terms

Microbiological Quality: Refers to the presence and concentration of microorganisms in water.

Membrane Filter Technique: A method for concentrating microorganisms from water samples onto a membrane filter for subsequent analysis.

Waterborne Diseases: Illnesses caused by ingesting water contaminated with pathogenic microorganisms.