AWWA WQTC64167

Engineered filtration media have an inherent advantage over conventional media (mined aggregates) in that physical properties are more uniform and certain attributes may be optimized. While substantial research exists regarding pathogen removal by conventional filtration, little information exists regarding pathogen removal by engineered filtration media; and, even less information exists regarding the optimization of engineered filtration media for pathogen removal. A pilot-scale filtration apparatus was utilized to evaluate the particle and pathogen removal performance of engineered ceramic media relative to conventional dual-media filtration during sub-optimal coagulation conditions. The pilot-scale filtration experiments were conducted with both synthetic and real waters at conditions representing complete coagulation failure and at load rates of 10 gpm/ft² (24.4 m/h) and 4 gpm/ft² (9.8 m/h). These investigations demonstrated that, depending on the media type and configuration utilized, engineered ceramic media could yield improved filter effluent turbidity and particle counts as well as an ~2-log advantage in oocyst-sized microsphere removal. The investigations reported herein were not conducted to elucidate specific filtration mechanisms, but rather to investigate optimized configurations of conventional and engineered ceramic media and to obtain and compare performance data to indicate whether engineered ceramic media may offer an opportunity to further optimize the performance of rapid gravity filtration processes. The promising outcomes of these studies have lead to mechanistic evaluations and further investigations of Cryptosporidium and oocyst-sized polystyrene microsphere removal by the pilot-scale conventional and engineered filtration media treating real source waters. Includes 17 references, figures.