Coliform
group of material is the principal indicator of pollution if present in any
water body; it means that the water is unsuitable for domestic and other uses.
group of material is the principal indicator of pollution if present in any
water body; it means that the water is unsuitable for domestic and other uses.
Apparatus
i.
Membrane
filtration equipment.
ii.
Pipette
(1ml pipette graduated in 0. 1ml).
iii.
Volumetric
flask.
iv.
Colony
counter.
v.
Petri
dish.
vi.
Vacuum
pump.
vii.
Absorbent
pad.
viii.
Incubator.
Incubator.
Reagents
1.
M-coliform
broth (MF Endo medium) weight 48g M coliform broth, dissolve in 20ml of ethanol
and make it to 1 liter with sterilize distilled water.
M-coliform
broth (MF Endo medium) weight 48g M coliform broth, dissolve in 20ml of ethanol
and make it to 1 liter with sterilize distilled water.
2.
Ethanol
Ethanol
Procedure
i.
Obtain
three petri-dish and put absorbent pads in each of them.
ii.
Withdraw
2ml as are found convenient, from the diluted sample made.
iii.
Make
each up to 100ml and then filter through membrane filter with aid of vacuum
pump.
iv.
Place
the filter membrane in the absorbent pad containing the solution. The broth
serves as the nutrient for the coliforms.
v.
Place
it in an incubator pre-set to 35.0+/-50c.
vi.
Incubate
for 24 hours.
vii.
Watch
out for greenish metallic shinning colonies on the filter membrane.
viii.
It
no colonies are observed, incubate further for another 12 hours (to give 26
hours of incubation altogether).
ix.
Count
the colonies formed.
Calculation:
Total
coliform/100ml= Coliform count x 100 x D
coliform/100ml= Coliform count x 100 x D
Vol.
(ml) diluted sample filtered.
(ml) diluted sample filtered.
