The paper analyses the performance of 166 wastewater treatment plants operating in Brazil. Six different treatment technologies have been investigated, comprising the following processes: septic tank + anaerobic filter, facultative pond, anaerobic pond + facultative pond, activated sludge, UASB reactors alone, UASB reactors followed by post-treatment. The objective of the research was to evaluate the effluent quality and the removal efficiencies of the parameters BOD, COD, TSS, coliforms, TKN and phosphorus. The paper compares the effluent quality and the removal efficiencies with typical values reported by the technical literature. In general, the performance in the removal of organic matter was as expected. TSS removal efficiencies were lower than reported, but coliform removal was higher than described in the literature. Nutrient removal was low, but none of the treatment processes have been designed with this objective.
Effluent quality; performance evaluation; wastewater treatment
