Final answer:
Primary sludge fermentation is used in wastewater treatment plants to remove phosphorus from wastewater through enhanced biological phosphorus removal, where specific bacteria convert the phosphorus in the primary sludge into polyphosphate compounds.
Step-by-step explanation:
Primary sludge fermentation is utilized in wastewater treatment plants to address the removal of phosphorus from wastewater through a process called enhanced biological phosphorus removal.
In this process, specific bacteria called polyphosphate accumulate organisms (PAOs) convert the phosphorus in the primary sludge into polyphosphate compounds, which are then stored within their cells.
These PAOs can be selectively enriched and encouraged to accumulate even more phosphorus by manipulating the conditions within the wastewater treatment plant.