- Take sample from same location(s) each time
- Perform exam as soon as possible. If doing exam after a few hours, make sure samples were refrigerated
- Use 100x and 400x magnification (10x and 40x objectives on most microscopes).
- Use phase contrast if possible. Phase contrast helps see more detail in living, unstained organisms.
- Make sure to note floc size, density, shape, filament abundance & location, and amount of solids outside floc
- Now note the protozoa which are much larger and easier to see than bacteria. Classified by locomotion, protozoa are indicators of toxicity, soluble BOD/COD, dissolved oxygen, and shocks to the biomass.
Microscopic exam is one of the easiest and most useful tests for monitoring biological wastewater treatment unit biomass. To make microscopic exam useful it is best to follow a few rules:
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