Microbial processes underlying the PETRO concept (trickling filter variant)

Natural phenomena underlying the operation of the PETRO (pond enhanced treatment and operation) system and its trickling filter (TF) in particular have been elucidated. Data obtained strongly indicate that the microalgae apart from bacteria, fungi, protozoa and rotifers play an important role within the TF biofilm consortium. Their stress-induced biofilm slime production under heterotrophic conditions in the TF, appears to greatly facilitate flocculation of solids which results in high performance of the TF, the clarifier and the system as a whole.