The ability of solar disinfection (SODIS) and solar photocatalytic (TiO(2)) disinfection (SPC-DIS) batch-process reactors to inactivate waterborne protozoan, fungal and bacterial microbes was evaluated. After 8 h simulated solar exposure (870 W/m(2) in the 300 nm-10 microm range, 200 W/m(2) in the 300-400 nm UV range), both SPC-DIS and SODIS achieved at least a 4 log unit reduction in viability against protozoa (the trophozoite stage of Acanthamoeba polyphaga), fungi (Candida albicans, Fusarium solani) and bacteria (Pseudomonas aeruginosa, Escherichia coli). A reduction of only 1.7 log units was recorded for spores of Bacillus subtilis. Both SODIS and SPC-DIS were ineffective against the cyst stage of A. polyphaga.