Filtration has been around for a long, long time, so it may be that most treatment plant operators feel pretty informed about its capabilities. But hearing from Brian Frewerd, Director of Application Engineering with Parkson Corporation and Water Talk guest, will likely prove enlightening. Frewerd provides background on sand filtration for tertiary treatment applications, followed by insight on notable technology improvements and performance milestones. "We [can] deliver effluent quality out of a sand filter that is equivalent to microfiltration," he states. Topics covered in the interview include the current state of regulations, the need for nutrient removal (and even nutrient recovery), and ways to fine-tune your filtration process.