Bacteria Count Labsheet
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Bacteria Count Labsheet...
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FACULTY OF CIVIL AND ENVIRONMENTAL ENGINEERING DEPARTMENT OF WATER RESOURCES AND ENVIRONMENTAL ENGINEERING ENVIRONMENTAL ENGINEERING LABORATORY
LABORATORY INSTRUCTION SHEETS
SUBJECT CODE EXPERIMENT CODE EXPERIMENT TITTLE COURSE CODE
BFC 3121 MA2 BACTERIA COUNT
KOD ETIKA PELAJAR (KEP) JAB. KEJ. SUMBER AIR & ALAM SEKITAR FAKULTI KEJURUTERAAN AWAM & ALAM SEKITAR UNIVERSITI TUN HUSSIEN ONN MALAYSIA. Saya dengan ini mengaku bahawa saya telah menyediakan laporan ini dengan daya usaha saya sendiri. Saya juga mengaku tidak menerima atau memberi sebarang bantuan dalam menyediakan laporan ini dan membuat ikrar ini dengan kepercayaan bahawa apaapa yang tersebut di dalamnya adalah benar.
___________________________ Tandatangan Pelajar Nama : _______________________________ No. Matrik :____________________________ Tarikh :________________________________
FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING
DEPARTMENT OF WATER RESOURCES AND ENVIRONMENTAL ENGINEERING ENVIRONMENTAL ENGINEERING LABORATORY SHORT REPORT SUBJECT CODE CODE & EXPERIMENT TITLE COURSE CODE EXPERIMENT DATE NAME OF STUDENT NO.OF GROUP GROUP MEMBER
NAME OF LECTURER/ INSTRUCTOR/TUTOR DATE OF SUBMISSION MARKS
1. 2. 3. 4. 5.
ATTENDANCE & DISCIPLINE INTRODUCTION RESULTS DATA ANALYSIS DISCUSSION CONCLUSION REFERENCES TOTAL
EXAMINER’S COMMENT
FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING DEPT : WATER RESOURCE & ENVIRONMENTAL ENGINEERING
/10% /5% /15% /15% /25% /5% /5% /80% APPROVAL RECEIVE
PAGE NO.:
1/5
EDITION:
MA2
LAB : ENVIRONMENTAL ENGINEERING
REVISION NO.:
03
EXPERIMENT : BACTERIA COUNT
EFFECTIVE DATE: AMMEND. DATE:
01/12/2007 20/11/2007
1.0 OBJECTIVE Students will be able to measure the bacteriological quality of water sample by performing total plate count. 2.0 LEARNING OUTCOMES At the end of the laboratory courses, students will be able to : 1. Be more proficient at dilutions. 2. Be more proficient at performing a standard plate count and determining bacterial counts in a sample. 3.0 THEORY Bacteria are remarkably adaptable to diverse environmental conditions: they are found in the bodies of all living organisms and on all parts of the earth–in land terrains and ocean depths, in arctic ice and glaciers, in hot springs, and even in the stratosphere. Our understanding of bacteria and their metabolic processes has been expanded by the discovery of species that can live only deep below the earth's surface and by species that thrive without sunlight or in the high temperature and pressure near hydrothermal vents on the ocean floor. There are more bacteria, as separate individuals, than any other type of organism; there can be as many as 2.5 billions of bacteria in one gram of fertile soil. Many studies require the quantitative determination of bacterial populations. The two most widely used methods for determining bacterial numbers are the standard, or viable, plate count method and spectrophotometric (turbidimetric) analysis. Although the two methods are somewhat similar in the results they yield, there are distinct differences. For example, the standard plate count method is an indirect measurement of cell density and reveals information related only to live bacteria. The spectrophotometric analysis is based on turbidity and indirectly measures all bacteria (cell biomass), dead and alive. The standard plate count method consists of diluting a sample with sterile saline or phosphate buffer diluent until the bacteria are diluted enough to be counted accurately. Hence, the final plates in the series should have between 30 and 300 colonies. Fewer than 30 colonies are not acceptable for statistical reasons (too few may not be representative of the sample), and more than 300 colonies on a plate are likely to produce colonies too close to each other to be distinguished as distinct colony-forming units (CFUs). The assumption is that each viable bacterial cell is separate from all others and will develop into a single discrete colony (CFU). Thus, the number of colonies should give the number of bacteria that can grow under the incubation conditions employed. A wide series of dilutions (e.g., 10-4 to 10-10) is normally plated because the exact number of bacteria is usually unknown. Greater accuracy is achieved by plating duplicates or triplicates of each dilution. Increased turbidity in a culture is another index of bacterial growth and cell numbers (biomass). By using a spectrophotometer, the amount of transmitted light decreases as the cell population increases. The transmitted light is converted to electrical energy, and this is indicated on a galvanometer. The reading, called absorbance or optical density, indirectly reflects the number of bacteria. This method is faster than the standard plate count but it has limitation where sensitivity is restricted to bacterial suspensions of 107 cells or greater.
PREPARED BY: BALKIS A. TALIP SIGNATURE: DATE: 20 NOVEMBER 2007 FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING DEPT : WATER RESOURCE & ENVIRONMENTAL ENGINEERING LAB : ENVIRONMENTAL ENGINEERING EXPERIMENT : BACTERIA COUNT
PAGE NO.:
2/5
EDITION:
MA2
REVISION NO.:
03
EFFECTIVE DATE: AMMEND. DATE:
01/12/2007 20/11/2007
4.0 EQUIPMENTS & MATERIALS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Petri plate Pipette Test tube Glass rod Bunsen burner Incubator Ethanol 95% @ methanol Sterilizer Microscope Bacteria medium: Peptone = 5g, Beef Extract=3g, Agar=15g, Distilled water=600 mL
5.0 PROCEDURES 5.1 Media preparation: Please prepare the nutrient media using the microbiology standard method. 5.2 Sample preparation: Prepare the serial dilution of the water sample using the appropriate dilution factor. 5.3 Plating procedures: Using the pour plate and spread plate method.
FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING DEPT : WATER RESOURCE & ENVIRONMENTAL ENGINEERING LAB : ENVIRONMENTAL ENGINEERING EXPERIMENT : BACTERIA COUNT
PAGE NO.:
4/5
EDITION:
MA2
REVISION NO.:
03
EFFECTIVE DATE: AMMEND. DATE:
01/12/2005 20/12/2005
6.0 RESULTS & CALCULATIONS / ANALYSIS Plating Method Pour Plate Spread Plate
Average Colony /plate 119
Dilution 1/10
1/100
1/1000
1/104
1/105
1/106
190
175
155
85
75
35
125
200
180
160
90
80
40
Total bacteria / mL
7.0 DATA ANALYSIS 1.
Show the calculation for each of the plating method and fill in the above table.
2.
Analyze the results by using appropriate method. Explain your findings.
3.
State the systematic bias error that could occur during this experiment.
4.
Usually, the results give different readings for both methods. However, in some cases, both methods produce the same results. Explain why the results are indistinguishable.
8.0 QUESTIONS 1.
Explain the meaning of a phrase “two times ten to the eight cells per mL” in your own convenient terminology.
2.
What the meaning of TNTC and the significant amount due to the TNTC? Give the formula for determining bacteria count.
3.
Design an experiment to compare the bacteria counts in different water samples (tapwater, lake water, swimming pool water and rainbarrel water). Explain the difference of bacteria count for each type of water sample?
4.
In many experiments there are 2 types of control used which are positive and negative control. Based on this experiment what is the suitable control? How will the control affect your findings?
1/100 1/10
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