19/07/2024
Two easy ways to monitor wastewater treatment performance
The observed parameter visual checks for the operator are MLSS color and foam changes are useful and great but need more tests including SV30, Dissolved oxygen, and MLSS.
Color
A healthy MLSS is brown and results from bacteria cells, biological polymers, and particulate materials.
1. Lightly brown, usually indicates immature biomass but
2. Dark colors - trending towards gray or black indicate older sludge, septicity, and if accompanied by odors, a problem with aeration or mixing and aerobic condition will be changed to the anaerobic condition (Low DO)
Foam
As the foam is directly related to biological activity, we can conclude as follows
1. Deep, white foam and stable - usually from influent surfactants
2. White foam, not stable under water spray (biological foam from normal bacteria action). White foam often indicates younger sludge and usually the bacteria growth in the log phase
3. Light brown foam, a normal condition in the Activated sludge process
4. Thick brown, stable greasy foam (often growth of Nocardia forms). These organisms thrive on long-chain fatty acids and long sludge ages. In this condition, excess sludge will be useful
5. Gray, indicator of "old" sludge or anaerobic conditions in the system.
