A Review Of Water Biology Essay

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Water is used for several purposes by humans but the level of purity of the water being consumed is very crucial since it has a direct effect on health. More than half of all illnesses and deaths among children are caused by germs, which get into the mouth via water and food. The World Health Organization has estimated that up to 80% of all disease and sickness in the World is caused by inadequate sanitation, polluted water or unavailability of water. Approximately three out of every five persons in the developing countries do not have access to drinking water and only one in four has any kind of sanitary facility, Cheesbrough, (1984), UNICEF, (1993).

Fortunately, the flora of Africa is rich with a lot of medicinal plants such moringa oleifera which people in the rural areas are quite familiar with and have been using them since time immemorial to treat water. Moringa oleifera belongs to the family Moringaceae which is a single genus family of shrubs and trees cultivated across the whole of the tropical belt and used for a variety of purposes Jahn, (1986).

The moringa tree pod contains a seed which, when crushed, is a natural coagulant. In the Sudan, dry Moringa oleifera seeds are used in place of alum by rural women to treat highly turbid Nile water Jahn, (1986). The dry seed suspension is known to be a natural coagulant and coagulant aid (Jahn, 1979-1988; Folkard et al., 1986-1988; Kaser et al., (1990); Sani, (1990); Bina, (1991).

Studies by Eilert et al. (1981) identified the presence of an active antimicrobial agent in Moringa oleifera seeds. The active agent isolated was found to be 4a L-rhamnosyloxy-benzyl isothiocyanate, at present the only known glycosidic mustard oil.

Madsen et al. (1987) carried out coagulation and bacterial reduction studies on turbid Nile water in the Sudan using Moringa oleifera seeds and observed turbidity reduction of 80-99.5% paralleled by a bacterial reduction of 1-4 log units (90-99.9%) within the first one to two hours of treatment, the bacteria being concentrated in the coagulated sediment.

1.2 Problem statement

The high cost of treated water makes most people in the rural communities to resort to readily available sources which are normally of very low quality exposing them to waterborne diseases. Therefore, there is need to research on the effectiveness of moringa oleifera in water treatment so that it may be employed in providing easy and safe means of potable water for rural population, since modern technology for potable water is limited, very expensive, and unavailable in those areas.

1.3 Objective

General objective

* To assess the effectiveness or efficacy of the powder processed from Moringa oleifera seeds powder as an antibacterial agent in water purification.

Specific objectives

* To determine the effective concentration of the moringa powder which has an effect on the bacteria found in water.

* To quantify the coliform bacteria in water incase they are present before and after treatment of water.

1.4 Justification

According to Postnote (2002), waterborne diseases are one of the main problems in developing countries; about 1.6 million people are compelled to use contaminated water and more than a million people (of which two million are children) die from diarrhea each year. Earlier research findings of Crapper et al. (1973) and Miller et al. (1984) showed that the chemicals used for water purification can cause serious health hazards if an error occurs in their administration during the treatment process. Therefore, there is need to investigate the use of non-chemicals which would be available locally in most developing countries. This will help in providing easy and safe means of potable water for rural population.

1.5 Scope of the study

This study is majorly concerned with the assessment of the effectiveness of moringa oleifera seeds powder extract in the disinfection of bacteria from water.

2.1 Water Borne Diseases

Contaminated drinking water is especially dangerous to humans because of the many diseases that it often transmits. These diseases fall into three major categories: bacterial (caused by bacteria in water), viral (caused by viruses in water), and parasitic (caused by a parasitic protozoa or worm in water). Below, I discusses each of these diseases one at a time within the context of this research.

2.1.1 Bacterial Diseases

The bacterial diseases that can result from polluted water include typhoid, cholera, bacterial dysentery, and enteritis. Typhoid resides in the bacterium Salmonella typhi, and it is often fatal if untreated. The symptoms and effects of typhoid include diarrhea, severe vomiting, an enlarged spleen, and an inflamed intestine. Another bacterial disease, cholera, is caused by the bacterium Vibrio cholerae. Its symptoms consist of diarrhea, severe vomiting, and dehydration, and, like typhoid, it is often fatal if left untreated. Bacterial dysentery is rarely fatal except in infants and its major symptom include diarrhea, abdominal pain, and cramps. Bacterial dysentery results from exposure to the bacterium Shigella dysenteriae. The final bacterial disease is enteritis, which is caused by the bacterium Clostridium perfringens. It is characterized by severe stomach pain, nausea, loss of appetite, and vomiting, and is rarely fatal. The presence of coliform bacteria in water is an indication of pathogenic bacteria.

2.2 Coliform bacteria

Coliforms are defined as facultatively anaerobic, gram negative, non -sporing, rod shaped bacteria that ferment lactose with gas formation within 48 hours at 350c, . Prescott (2002).

Coliform bacteria are commonly found in soil, on vegetation, and in surface waters. They also live in the intestines of warm blood animals and humans. Some coliform bacteria strains can survive in soil and water for long periods of time. Coliform bacteria will not likely cause illness in people, however because coliform bacteria are most commonly associated with sewage or surface waters. , tThe presence of coliforms bacteria in water indicates that other disease causing organisms may be present in the water source or its distribution system, Postgate (1992).

There are three different groups of coliform bacteria, and each has a different health risk.

Total coliform bacteria are commonly found in the environment e.g. soil or vegetation and are generally harmless. If total coliform bacteria are detected in water, the source is probably environmental, and fecal contamination is not likely. However, if environmental contamination can enter the system, there may be a way for other pathogens to enter the system, Prescott (2002).

Feacal coliform bacteria are a sub group of the total coliform group. They appear in great quantities in the intestines and feaces of people and animals. The presence of feacal coliforms in a drinking water sample often indicates recent feacal contamination meaning that there is a greater risk that pathogens are present than if only total coliform bacteria are detected.

Escherichia coli (E.Coli) is a subgroup of the feacal coliforms group. Most E.Coli is harmless and is found in great quantities in the intestines of people and warm blooded animals. Some strains however may cause illness. The ability of E.coli to survive for brief periods outside the body makes them an ideal indicator organism to test environmental samples for fecal contamination. The presence of E.Coli in a drinking water sample always indicates recent feacal contamination meaning that there is a greater risk that pathogens are present. E.Coli outbreaks have been related to food contamination, caused by specific strains of E.Coli. When a drinking water sample is reported as “E.Coli present” it does not mean that a specific strain is present. However, it does not indicate recent feacal contamination. Treating contaminated drinking water with a disinfectant or boiling the water destroys all E.Coli.

2.3 How coliform bacteria get into water

Mary and William Cunningham (2004) maintain that the purity of water is known to vary drastically due to its being a universal solvent. I, that is, it dissolves a number of elements and chemicals or compounds in addition to providing a conducive habitat for a diversity of living micro and macro organisms. As rain falls through the air, atmospheric gases dissolve in it together with other solutes which include elements, chemicals, compounds and micro organisms.

Underground and surface water may be polluted by decaying organic matter of plants and animals, sewage and industrial waste as water bodies are used by man to dispose off these wastes in an attempt to minimize or neglect the expense of waste treatment.

The pathogens in these wastes multiply within the water body making it a source of unsafe water if consumed without effective preparation and or treatment, delivery and storage.

2.4 Moringa oleifera general information
2.4.1 Description

A native of northern India, M.oleifera is now grown widely throughout the tropics. It is Sometimes known as the drumstick' or ‘horseradish' tree. Ranging in height from 5 to 12m with an open, umbrella-shaped crown, straight trunk and corky, whitish bark, the tree produces a tuberous tap root. The evergreen or deciduous foliage (depending on climate) has leaflets 1 to 2 cm in diameter; the flowers are white or cream coloured. The fruits (pods) are initially light green, slim and tender, eventually becoming dark green, firm and up to 120cm long, depending on the variety. Fully mature, dried seeds are round or triangular, the kernel being surrounded by a lightly wooded shell with three papery wings.

2.4.2 Climate and soil conditions

The M. oleifera prefers hot, semiarid regions (annual rainfall 250- 1500mm), although it has been found to adapt well to hot, humid, wet conditions with annual rainfall in excess of 3000mm. Considered to be suitable only for lowland cultivation at altitudes less than 600m, the adaptability of the tree was demonstrated by the discovery of natural strands at altitudes of 1200m in Mexico. Although preferring well-drained sandy or loamy soils, heavier clay soils will be tolerated, although water logging should be avoided. The tree is reported to be tolerant of light frosts and can be established in slightly alkaline soils of up to pH. 9.

2.4.3 Cultivation of moringa oleifera

The tree grows rapidly from seeds or cuttings, and growth up to 4m in height; flowering and fruiting have been observed within 12 months of planting out. In areas where the climate permits, e.g. central of Uganda, two harvests of pods are possible in a single year. Recent estimates suggest that, for a spacing of 3m, a likely annual seed yield is 3 to 5 tones per hectare.

2.4.4 How the Moringa oleifera seeds work

The seed kernels contain significant quantities of a series of low molecular weight, water-soluble proteins which, in solution, carry an overall positive charge. The proteins are considered to act similarly to synthetic, positively charged polymer coagulants. When added to raw water the proteins bind to the predominantly negatively charged particulates that make raw waters turbid (silt, clay, bacteria etc.). Under proper agitation these bound particulates then grow in size to form the flocs, which may be left to settle by gravity or be removed by filtration. Findings support recombinant proteins both removing microorganisms by coagulation as well as acting directly as growth inhibitors of the microorganisms.

2.4.5 Are the seeds of Moringa oleifera toxic?

Studies have been carried out to determine the potential risks associated with the use of the seeds in water treatment. To date, all the studies have concluded that there is no evidence to suggest any acute or chronic effects on humans, particularly at the low doses required for water treatment.


3.1 Extraction of moringa PowderSamples used

The seeds will be harvested when they are fully matured. Mature seds This will be determined by observing if there are any dry cracked pods on the plants. The pods that are plucked are to will be cracked to obtain the seeds which will be air-dried at 40°C for two days. The shells surrounding the seed kernels will be removed using a knife and the kernels will be pounded using a laboratory mortar and pestle into powder and sieved using a strainer with a pore size of 2.5 mm2 to obtain a fine powder.

3.2 Experimental design

A Completely Randomised Design is to be used for this experiment. The treatments given will be the varying concentrations of powder produced from Moringa seeds, and the control (no Moringa seed powder). The treatment effect on the response for total coliform counts will be carried in triplicates. And how many replicates of each set of expt?

3.3 Sample preparation

Five (5) litres of water sample will be fetched from a well situated in the valley behind Kira town centre. This will then further be dispensed into 6 beakers. The volume of sample in each beaker will be 500 ml. Then five different concentrations of the stock solution for the loading dose will be prepared by weighing 2.0, 4.0, 6.0, 8.0 and 10.0g of Moringa oleifera seed powder extract separately into a beaker containing 500 ml of distilled water. The mixtures in the beakers will be stirred using a glass rod to obtain a clear solution. A 500 ml of distilled water with no Moringa seed powder extract will be kept foras the control treatment.

3.4 Laboratory analyses

The jar test will be used. A 2 ml of the various concentrations including the control of all the loading dosages prepared will be measured into a beaker containing 500 ml of the samplewell water. The solutions will be mixed rapidly for 2 minutes; followed by 10 minutes of gentle mixing using a sterile glass rod to aid in coagulant formation. The suspensions will be left to stand without disturbance for 1 hour. This is the method adopted since there is no standard method for conducting the jar test, Ndabigengesere et al. (1995). The supernatants formed will be decanted and subjected to total coliforms count measurements.

3.5 Total coliform using most probable number (MPN) test

In determining the most probable number of coliforms that will be present in each of the treated water samples, the multiple tube fermentation method will be adopted. MacConkey broth will be used as the medium for the bacteria growth. Two types of the MacConkey broth will be prepared. These are the single strength MacConkey broth (SSMB) and the double strength MacConkey broth (DSMB). In the single strength, 6.5 g of the MacConkey powder is to be weighed and dissolved in 500 ml of distilled water. The solution will then be stirred gently for 10 minutes on a magnetic stirrer to dissolve and mix well. The double strength will be prepared using exactly a double of each oftwice the weights of the reagents used. This solution will also be put on a magnetic stirrer and stirred gently for 10 minutes.

An estimate of the number of the coliforms (most probable number) will be done in the presumptive test. In this procedure, 15 tubes with 15 ml of MacConkey broth will be inoculated with treated water samples and the control at different intervals. 5 tubes will receive 10 ml of water, the MacConkey used will be double strength for this case, other 5 tubes will receive 5 ml of water and the last 5 tubes will receive 1 ml of water., here tThe last 10 tubes will contain single strength MacConkey broth. The test tubes will then be incubated for 24 - 48 hours at 37°C beforeafter which they canwill be analysed.

3.6 Sample analysis

A count of the number of tubes showing gas production will then be made, and the figure will be compared to a table developed by the American Public Health Association (APHA 1995). The number will be the most probable number (MPN) of coliform per 100 ml of the water sample.


Appendix4.1: Work plan





















4.3 References

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