Membrane filtration (expriment) - Lab Report Example

As potable water is procured from surface sources such as rivers, streams and lakes, bacteriological examination is crucial to determine the safety of drinking water. Presence of Enterococcus faecalis, Escherichia coli, Enterobacter aerogens and Proteus mirabilis in water sample was estimated using membrane filtration followed by incubation of the membrane filter in appropriate growth media to examine the determine the presence of pathogenic micro-organism. The motive to perform this study was to determine the presence of unknown organism(s) present in the provided samples.

The study encompasses classification of bacteria based on their bio-chemical reactions, pH levels and osmoregulation. Identification and classification of bacteria from the sample is pragmatic as presence of any pathogenic micro-organism could be deleterious to health. Identification of bacteria provides line of treatment. The three preliminary steps for the analysis procedure comprise principal isolation, staining and biochemical reactions as the samples may contain diverse microorganism belonging to different species.

Hypothesis to be tested: (1) Fecal coliform count of surface water samples differ according to their location. (2) Fecal coliform count of surface water samples do not differ according to their location. Introduction Microbes are indispensible module of our environment. They are associated in a variety of ways with everything we use in our everyday lives (Fratamico, 2005). They are found to be associated with the food that we eat, the clothes we wear/make use of and water we drink/utilize. They may perhaps influence the quality of our lives and transmit numerous diseases (Fratamico, 2005).

It is therefore essential to understand the microbes linked with the commodities used in everyday life. Water free from disease-producing microorganisms and chemical substances deleterious to health is called potable water. Water contaminated with either domestic or industrial wastes is called non-potable or polluted water. The objectives of primary concern in providing potable water are freedom from harmful microorganisms and from undesirable chemicals. Water appearing clean or free from peculiarities of odor and taste could be contaminated.

In such conditions special procedures are required to determine its sanitary quality. Inspection of water sample involves the inspection of the source of raw water and the conditions that may influence its quality. Changes related to population, types of industry and the method of sewage disposal are imperative. Practically, periodic and comprehensive sanitary surveys are necessary. However, potability can be determined only by chemical and bacteriological laboratory tests (Pelczar, 1993). Pathogens that gain entry into the water body include protozoan such as Giardia and Cryptosporidium, bacteria such as Campylobacter, Salmonella and Shigella and virus associated with water contamination are Hepatitis A virus and Norwalk virus.

However, water is tested for the fecal contamination. As coliforms are discharged through feces the water sample containing fecal matter comprises pathogenic organisms as well. Essentially water sources such as wells, reservoirs, and storage tanks are routinely tested for water safety (Case Study Exercise 29: Measure of Water Quality: Membrane Filtration Method). Lifestyle modifications and