Microbiological and Chemical Techniques for Testing Drinking Water.pptx

Water testing

1. Microbiological and Chemical Techniques for Testing Drinking Water Presented By: Muhammad Hussain Taqi Applied Microbiology (7th)

2. Introduction Water Contamination : Water Can Be Contaminated By Biological (E.G., Bacteria) And Chemical (E.G., Heavy Metals) Pollutants. Purpose Of Testing : To Ensure Water Is Free Of Harmful Substances That Can Cause Diseases Or Health Complications Impact : Understanding The Importance Of Water Testing Helps Us Appreciate The Role It Plays In Safeguarding Human Health.

3. Types of Water Contaminants There Are Two Major Types Of Contaminants : Microbiological (Living Organisms) And Chemical (Non-living Substances). Microbiological Contaminants : Include Pathogens Like Bacteria (E.G., E. Coli ), Viruses, And Protozoa That Cause Diseases. Chemical Contaminants : Include Harmful Chemicals Like Heavy Metals (E.G., Lead), Organic Pollutants (E.G., Pesticides), And Inorganic Compounds (E.G., Nitrates).

4. Microbiological Techniques Microbiological Testing Methods Are Critical For Identifying Disease-causing Organisms In Water. Common Pathogens : Include E. Coli , Fecal Coliforms, Salmonella , Giardia , And Cryptosporidium . Testing Importance : These Tests Are Necessary To Prevent Waterborne Diseases And Ensure The Microbial Safety Of Drinking Water.

5. Coliform Testing Coliform Bacteria (Especially E. Coli ) Serve As Indicators Of Fecal Contamination. Purpose : Coliforms Indicate Possible Contamination By Pathogens, Especially From Human Or Animal Waste. Methods : Membrane Filtration : Water Is Filtered, And Bacteria Are Captured On A Membrane. The Membrane Is Placed On Growth Media, And Any Coliforms Present Will Form Visible Colonies. Multiple-tube Fermentation ( Mtf ) : Water Is Placed In Test Tubes With Growth Medium, And The Production Of Gas Indicates The Presence Of Coliforms. Colilert Method : Uses Reagents That React With Coliform-specific Enzymes, Resulting In A Color Change Or Fluorescence, Indicating Coliforms Are Present.

6. Membrane Filtration Method This Method Is Used To Detect Bacteria By Filtering Water Through A Membrane That Captures Microorganisms. A Water Sample Is Passed Through A Membrane With Tiny Pores. The Membrane Traps Bacteria. The Membrane Is Then Placed On A Nutrient Medium To Allow Bacteria To Grow. Bacterial Colonies Are Counted To Estimate The Concentration In The Original Sample.

7. Multiple-Tube Fermentation (MTF) MTF Is Used To Detect The Presence And Quantity Of Coliform Bacteria In Water Samples By Observing Gas Production In Test Tubes. Water Is Added To A Series Of Test Tubes With Nutrient Broth. The Tubes Are Incubated For 24–48 Hours. Gas Production In The Tubes Indicates The Presence Of Coliform Bacteria. The Most Probable Number ( Mpn ) Of Coliform Bacteria Is Calculated Based On The Number Of Positive Tubes.

8. Enzyme-Substrate Coliform Test (Colilert) The Colilert Method Is A Rapid Way To Detect Coliform Bacteria And E. Coli Using Enzyme-substrate Reactions. The Colilert Reagent Is Added To The Water Sample. If Coliforms Are Present, The Substrate Reacts With Coliform-specific Enzymes, Leading To Color Changes Or Fluorescence. A Yellow Color Indicates The Presence Of Coliforms, While Fluorescence Under Uv Light Confirms E. Coli .

9. Additional Microbiological Techniques Other Advanced Microbiological Methods Are Used For More Specific Or Comprehensive Testing. PCR (Polymerase Chain Reaction) : Amplifies DNA Of Specific Pathogens, Allowing Detection At Very Low Concentrations. Elisa (Enzyme-linked Immunosorbent Assay) : Detects The Presence Of Specific Antigens Or Toxins Produced By Microorganisms. Heterotrophic Plate Count (HPC) : Measures The Overall Bacterial Population In Water Samples.

10. Chemical Techniques Overview Monitoring For Chemicals Like Lead, Mercury, Pesticides, And Nitrates Is Crucial To Ensure Drinking Water Is Safe. Categories : Heavy Metals : Lead, Arsenic, Mercury. Organic Pollutants : Pesticides, Industrial Chemicals. Inorganic Compounds : Nitrate, Fluoride.

11. Spectrophotometry Spectrophotometry Is A Technique Used To Measure The Concentration Of Substances In Water Based On Light Absorbance. A Reagent Is Added To The Water Sample. The Spectrophotometer Measures The Absorbance Of Light By The Sample. The Absorbance Value Is Used To Calculate The Concentration Of The Contaminant (E.G., Nitrates Or Chlorine). Common Applications : Detection Of Nitrate, Phosphate, Or Chlorine Levels In Water.

12. Atomic Absorption Spectroscopy (AAS) AAS Is Used To Detect And Measure The Concentration Of Metals In Water Samples. The Sample Is Atomized (Converted Into Free Atoms). Light Of A Specific Wavelength Is Passed Through The Sample, And The Amount Absorbed By The Atoms Is Measured. The Amount Of Light Absorbed Correlates With The Metal Concentration. Common Uses : Lead, Mercury, Arsenic Detection.

13. Gas Chromatography-Mass Spectrometry (GC-MS) GC-MS Is Used To Separate And Identify Volatile Organic Compounds ( Vocs ) And Pesticides In Water. The Sample Is Vaporized In A Gas Chromatograph. Compounds Are Separated Based On Their Interaction With The Chromatography Column. Mass Spectrometry Is Used To Identify The Chemical Structure Of Each Compound. This Method Is Highly Sensitive And Accurate For Detecting Harmful Organic Pollutants.

14. Ion Chromatography (IC) IC Is Used To Measure Concentrations Of Ions Like Fluoride, Chloride, And Nitrate In Water. A Water Sample Is Injected Into A Chromatography Column. Ions Are Separated Based On Their Charge And Interaction With The Column Material. A Detector Measures The Amount Of Each Ion. Common Applications : Measurement Of Anions And Cations In Drinking Water.

15. Conclusion . Key Points : Combination Of Methods : Comprehensive Water Testing Requires Both Microbiological And Chemical Techniques To Detect A Wide Range Of Contaminants. Public Health Impact : Regular And Accurate Testing Helps Protect Public Health And Ensure Safe Drinking Water. Future Focus : Emphasize The Need For Continuous Monitoring And Advancements In Water Testing Technologies.