Biofilter performance is critically dependent on maintaining the integrity of the biofilm on the filter media. When this is compromised, performance suffers and this tends to initiate a positive feedback loop whereby impaired performance drives further performance impairment.
In Systems Theory terms, degradation of this biofilm is an example of progressive disruption at the margin. By designing solutions to re-establish the integrity and performance of the biofilm, performance of the biofilter can be optimized to ensure effective nutrient and contaminant removal.
In this case the accumulation of organic solids in the biofilter impairing performance was clearly visible.