| Abstract: | Ozonation can improve the effluent characteristics of UASB (upflow anaerobic sludge blanket) reactors treating domestic sewage, by removing organic matter, solids, surfactants, color and microorganisms. In Brazil, part of the effluent of a 120 msup3; UASB reactor, fed with screened domestic sewage at an hydraulic retention time of 7 hours, was post-treated in a two-column ozonation system of 300 liters total volume. With a contact time of 50 minutes and ozone application dosage of 16.7 mg/L, the following removals were obtained at the ozonation step: 51‰ BOD, 56‰COD, 76‰ TSS, 62‰ color, and 91‰ surfactants. Pathogens and indicator organisms were inactivated to over 99.9‰. Ozonation completely destroyed Salmonella, protozoa cysts and helminth eggs and larvae. |
