Water Analysis : To determine the potability of water by MPN Test

AIM : To determine the potability of water by MPN Test



INTRODUCTION:
Water which receives animally & human which form a primary source of water borne disease. Direct testing procedures capable of detecting & quantifying the full spectrum of pathogens & identifying their source is time consuming process because of their variable occurrence, survival rate & origin; hence an indicator system has been identified as a best method for evaluating the microbiological quality of water.
A fecal coli form test is considered as most reliable test available for detesting  the presence of contamination of an intesting origin, the coli form group comprises all aerobic & facuttative an aerobic, gram –ve  non spirulating, rod shaped bacteria that ferment lactase with gas format within 48hrs at 35 ˚c.
REQUIREMENTS:

  1. Single strength of sactose bile growth (10 ml) -10 test tube
  2. Double strength of sactase bile growth (10 ml) - 5 test tube
  3. Water sample
  4. Sterile pipettes  
  5. Mac Cankey broth
PROCEDURE:
 

-      Distribute 10ml single strength lactase broth each to test tubes.
-      Add 10ml of double strength lactase broth in each of test tubes.
-      Introduce the Durhalm’s wial in all test tubes & sterilize them at 121˚c for 15 min.
-      Inoculate 10ml of water sample to all double strength lactose broth tubes.(DSLB)
-      Inoculate 1ml water sample to each of 5 SSLB tubes & 0.1ml of water sample to remaining 5 SSLB tubes.
-        Incubate all the tubes at 37˚c for 24hrs.
-       If gas is formed in 24hrs indicate +ve test. If no gas is formed in 24 hrs, incubate for next 24 hrs. If no gas is formed even after 48 hrs of incubation test is –ve.
-        Count the no. of +ve tubes in each dilution.
-        Determine the MPN by Mc Cardy’s table.

 

Comments

Post a Comment

Popular posts from this blog

Process of Wastewater Treatment Plant

Image
PROCESS OF WASTEWATER TREATMENT PLANT : Wastewater enters the treatment plant First it goes through a fine screen, next to aerated grit chamber, and then enters the primary clarifier. Sludge settled in the primary clarifier is sent to the fermenters and then to digesters. After the primary treatment, wastewater flows into (BNR) bioreactors. The activated sludge is separated in the following secondary clarifier. The clear effluent flows into Ultraviolet (UV), then to River. Settled activated sludge in the secondary clarifier is pumped back to BNR. Excess sludge is pumped into the dissolved air floatation (DAF) unit for thickening. Wastewater is collected in sanitary sewers (a complex network of underground pipes). Upon reaching the treatment plant, the wastewater flows through a series of treatment processes which remove the wastes from the
Read more

Water Analysis : Estimation Of Nitrate Nitrogen In Given Water Sample

INTRODUCTION: Nitrate is found only in small amounts in fresh domestic wastewater but in the effluent of nitrifying biological treatment plants nitrate may be found in concentration up to 30mg nitrate as nitrogen/L. It is essential nutrient for many photosynthetic autotrophs and in some cases has been identified as the growth-limiting nutrient. Generally 10mg nitrate nitrogen/L of drinking water is recommended to prevent disorder called methemoglobinemia in infants. Determination of nitrate nitrogen is difficult because of the relatively complex procedure. Although UV technique that measures the absorbance of nitrate at 220nm is suitable for measuring nitrate in wastewater. PRINCIPLE: This technique is useful for the screening of sample that has low organic content that is uncontaminated natural water and potable water supplies. The nitrate calibration curve follows Beer's Law up to 11 mgN/L. Measurement of UV absorbance at 220nm enables rapid determination of nitrate
Read more

Water Analysis : To Estimation Of Total Suspended Solids(TSS)

PRINCIPLE: A well mixed sample is filtered through a weighed standard glass fiber filter and the residues retained on the filter are dried to a constant at 103 ° C to 105 ° C. The increase in the weight of the filter represents the total suspended solids. If the suspended material clogs the filter and prolonged filtration, the differences between the total solids and total dissolved solids may provided an estimate of the total suspended solids. REQUIREMENTS: ·          Glass fiber filters ·          Filtration device ·          Weighing balance PROCEDURE: ·          Oven dry the glass fiber filter and weigh it. ·          Assemble filtering apparatus and glass fiber filter. ·          Wet filter with a small volume of distilled water to seat it in filtration apparatus. ·          Shake the given water sample and add 100 ml of it on filter. ·          Start the suction device to generate vacuum and filter out the water sample ·          Carefully re
Read more