Microfiltration and UV disinfection are two alternative technologies for wa
ter reclamation. The results of a pilot study combining these two processes
are presented. In addition to producing filtrate turbidities averaging 0.0
6 nephelometric turbidity units, microfiltration was an effective barrier t
o pathogens, demonstrating average log reductions of 4.5 for total coliform
s and 2.9 for MS2 bacteriophage. Ultraviolet disinfection following microfi
ltration reliably met the California Wastewater Reclamation Criteria (Title
22) total coliform standard of 2.2 colony-forming units/100 mt at a UV dos
e of 450 J/m(2). The MS2 bacteriophage standard, which requires a 5-log red
uction, was achieved by microfiltration and a UV dose of 880 J/m(2). A mode
l of the kinetics of inactivation of MS2 bacteriophage was used in further
analysis of disinfection data. The model indicated that considerable backmi
xing occurred in the pilot UV disinfection unit, and observed UV doses coul
d be reduced with improved hydraulics.