Evaluation Of Microbiological Quality Of Water Using The Membrane Filter Technique

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The examination of underground water source (well water) at campus III of Institute of Management and Technology (IMT), Enugu was carried out, by using ten samples of the water sample. Membrane filter technique for water quality was carried out for microbial count. For viable plate count for presence of pathogenic organisms and organisms indicating organicmatter pollution, plating technique of pour plates were used. Also presence of coliform group and Escherichia coli were examined using presumption coliform test, confirmatory and completed test techniques. The media used include nutrient agar, MacConkey agar, Brilliant green bile agar, MacConkey broth. The total viable plate count gave 6CFU per each plate for pathogenic organisms and organisms indicating organic matter pollution whereas the presumptive test showed the presence of coliform groups in eight samples out of ten samples out of ten sample and presence of Escherichia coli in seven samples out of ten. The confirmatory test showed the presence of coliform group in six samples out of ten and presence of E. coli in four samples out of ten. Whereas, the completed test gave the highest coliform count of 2 CPI in one samples and I CFU each in three samples, while only one sample out of ten gave I CFU for Escherichia coli count. And the mean count for coliform for the completed test was 0.6 CFU. The results indicated the presence of coliform and E coli, but the microbial load was minimal in all the tests. Therefore, the underground water source (well water) at campus III of institute of management and Technology (IMT), Enugu is not fit for drinking though can be used for washing, laundering, cooking and bathing.





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 as Escherichia 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.




i)            To isolate bacterial contaminations of under ground water (well-water).

ii)          To determine if there is faecal contamination under ground water sources

iii)        To determine the microbial load of underground water source (well-water).

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Evaluation Of Microbiological Quality Of Water Using The Membrane Filter Technique