The objectives of this powerpoint presentation were: to present representative results from lab and field studies conducted to evaluate the effect of oxidants on particle removal in granular media filters, recognizing the role of biology/photosynthetic activity; and, to present follow-up work conducted at the Onondaga County Water Authority, including unintended consequences of switching pre-oxidants. The four oxidants studied were ozone, chlorine, chlorine dioxide, and potassium permanganate. Results of the field studies are provided, along with lab filtration studies and design criteria. A case study is provided of the Onondaga County Water Authority. The goals of the AwwaRF Project 2725, Using Oxidants to Enhance Filter Performance, are listed and include: to determine the conditions under which oxidants can be used to enhance the removal of particles by coagulation and filtration; to better understand the mechanisms of oxidant-enhanced particle removal; to determine the conditions under which it will occur; and, to develop design and operating criteria to promote oxidant-enhanced particle removal.