DESEMPE？O DE UNA LAGUNA ANAEROBIA CON BAFLE DIVISOR SEGUIDA DE UNA LAGUNA FACULTATIVA, POSIBLE AFECTACIóN DE LA SALUD PúBLICA

the main objective in this research was to evaluate the efficiency of the sewage treatment plant of santa fé do sul city (s？o paulo) and to define possible effects on public health produced by the final effluent quality. a bathymetric study of the anaerobic with baffle and facultative stabilization ponds was done in order to define the sludge accumulation profile; the raw influents and the lagoons effluents were monitored during 24 consecutive hours to diagnose the plant performance. the average efficiency of the biochemical oxygen demand was 89%, higher than the minimum efficiency allowed by the brazilian current legislation. the amount of fecal coliforms highly exceeds the permitted values; however the settleable solids concentration achieved the environmental regulation with values lower than 1, 0 ml/l. the results indicated that the station requires maintenance works at the anaerobic pond, a better operational control and more effective maintenance. it was shown the need to install a post treatment system to guarantee the reduction of the fecal coliforms at the final effluent as an action to diminish the public health possible risks in the discharge zone and downstream of the final dump point.