- Floc size & density - simply look at floc shape, size, and density. You are looking for changes and relating what you see under the microscope to effluent quality. To see changes, you need to look at the biomass often!
- Indicator organisms - bacteria are usually too small to see under a low cost microscope, and aside from general shapes and motility, you don't see much. So, we look at indicator organisms which are much larger and more active than bacteria. As with the floc, you are looking for changes in indicator protozoa and metazoa (if present). Don't worry too much about exact ID for the protozoa. Look for general location methods, size, and relate what is there to your own system's operations. I have attached a "bug poster" for easy use in classifying common wastewater protozoa. Insteand of photos, I use drawings which makes you focus on the locomotion and main characteristics rather than exactly matching photos. By looking at the MLSS frequently, you learn what should be in your system when it is in good shape.
So just dust off the old microscope and start using it daily. A quick 5 minute look under the microscope using 10x and 40x objectives will give you good information and help improve your monitoring program.
If you don't have a bug poster near your microscope, I have included one that we made for Aster Bio here.