Activated sludge and other microscopic analysis

The microscopic analysis of activated sludge is an established and partially standardized method for assessment of biologically active sludge or organic nursery in wastewater technology (activated sludge, fixed-bed reactors, trickling filters).

By evaluating the floc structure and the settlement gives important clues about the performance or cause damage to the “biology” and the cleaning method to the bioreactors. Similarly, as in the biological water examination, many organisms a pointer value, so that after the determination of the type and frequency of the dominant organisms can draw conclusions about the composition of the wastewater or irregularities in its operations. It can be considered, whether the activated sludge, for example, suffers from lack of oxygen, or whether filamentous bacteria affect the settling behavior.

The filamentous bacteria is if they still have a special significance because they are among the major polluters of the dreaded Blächschlamms. Thread-shaped bacteria can increase the surface of the activated sludge floc so that the sediment in the clarification of the treated wastewater into the downstream sedimentation no longer fast enough. The situation is similar with some types of bacteria that have hydrophobic (water repellent) properties, so that the flakes condense on the surface of a floating ceiling. By denitrification can occur scum, if appropriately hydrophobic microorganisms dominate in the activated sludge and include the resulting nitrogen bubbles in the floc. All these phenomena lead to the drift of bacterial biomass in the effluent, so that often exceeded the limits specified sequence (accident) and load of the water.

Important tools in the determination of filamentous bacteria staining methods such as the Gram stain (cell wall) and the Neisser staining (polyphosphate granules) are to make the characteristic properties of the cell wall or cell structure visible.