Although the results obtained by different experimental methods and design should be compared only tentatively, the performance shown by both plants at removing BOD, COD and TSS was similar and even higher(between 63 and 93% forBOD, 50 and 88% for COD and 58 and 93% forTSS) when compared with performances obtained by other authors (between 65 and 91% forBOD, 48 and 75% forCOD and 58 and 88% forTSS; Mandi et al., 1998; Billore et al., 1999 and Tanner, 1996).