MEMBRANE FILTRATION
To determine the what microorganisms are in the groundwater, membrane filtration is used as it is one of the most simple and effective ways in the determination of microorganisms. Testing for microorganisms must be done before and after treatment of the water to first see what microorganisms are in the groundwater and to ensure that there are no microorganisms after the treatment of the groundwater. It was determined that the only problematic microorganism that can be found in Alberta's groundwater is limited to E. Coli.
MEMBRANE FILTRATION PROCESS
STEP 1:
Dilute the sample and setup a vacuum filtration system. Slowly pour the diluted sample into the funnel where the membrane is, and allow the vacuum to completely draw the liquid through the filter. The membrane filter will allow the liquid to go through while also trapping any microorganisms such as E. Coli. The membrane also have a printed mm-grid to allow the counting of the number of colonies to be easier.
STEP 2:
Carefully remove the membrane filter from the funnel using forceps and place it in a petri dish where it can be stored and incubated at either 22 or 37 °C to allow the E. Coli to form colonies. The sample is incubated until there are 30 to 300 colonies of E. Coli to ensure the interpretation is reliable and that there are no overlapping colonies that makes it hard to count, the incubation period is around 24 hours. Step 1 and 2 should be done multiple times to obtain multiple plate sets to reduce variations and error, one set of plate from each sample should be placed in either 22 °C or 37 °C in case either temperature does not promote colony growth.
STEP 3:
Once the sample have been sufficiently incubated and 30-300 colonies of E. Coli have been formed, the petri dish containing the membrane filter and the microorganisms are placed under a microscope to allow for counting of the number of colonies. A microscope is usually not necessary as the colonies should have grown large enough to be easily seen and counted by the naked eye. Through membrane filtration, the different types of microorganisms can be determined.
