Full Scale Implementation, Operation, and Performance of a Structured Sheet Media IFAS System

This case study has shown that existing CAS facilities can be economically retrofitted with structured sheet media to achieve enhanced nitrification. Performance data collected for more than one year has confirmed that the structured sheet media IFAS system was able to consistently meet the ammonia discharge limits even in concurrent wet and winter weather (e.g. 7–9°C at over three times design flow). The IFAS system has also proven to operate similarly to the prior CAS process and requires little attention from the operator. In the typical plug-flow structured sheet media IFAS system, tapered aeration with fine bubble diffusers was utilized to minimize filamentous growth, improve solids settleability, optimize kinetic rates, and provide energy savings. Additionally, as a benefit for the system installation, the rigid and stackable media blocks allowed for a simple retrofit of the existing aeration basin without the need for constructing baffle walls or media retention sieves.