AWWA WQTC60659

The objective of this study was to evaluate pilot scale advanced treatment processes to assess the removal efficacy after barriers that include: coagulation and flocculation; clarification; filtration; disinfection; and, the finished product. Challenge testing evaluated the removal efficacy of clarification, granular media filtration, and ultrafiltration. In all, eight challenges using waterborne microorganisms and pathogen surrogates were performed using the processes: SuperP blanket clarifier, Actiflo microsand ballasted clarifier, Granular dual media filters, and Zenon ZeeWeed 500-C ultrafilter. Each process was challenged with pathogen surrogates including bacteria (E. coli), bacteriophages (MS-2 & PRD-1), and 3mm latex beads (surrogates for Cryptosporidium oocysts). Efficacy of removing background levels of bacteria and viruses was also evaluated. Results indicated that the effectiveness was cumulative. The highest coliform removal was observed after the clarifiers with between 2.3 and 2.7 Log₁₀ removed for both the Super Pulsator and Actiflo systems. Clarifiers removed 3.5 and 3.3 log₁₀ of beads for Super Pulsator and Actiflo, respectively. The media filtration steps downstream showed further coliform removal with between 0.9 and 1.6 log removal for Super Pulsator and Actiflo, respectively. Bead removals by the media filters were 2.9 and up to 3.8, respectively. Zenon ultrafiltration removed up to 8.5 log₁₀ of the challenged beads and no coliforms were detected in the filtrate. These data suggest that under proper conditions, all three treatment processes were effective at removing coliforms and beads. Includes 11 references, tables, figures.