This paper deals with the aerobic biological treatment of industrial wastew
aters by aerated lagoons, when high flowrates are involved. A methodology i
s developed which gives the best fit between the biologic al reactions and
the ideal hydrodynamic behaviour of the lagoon. This analysis, based on the
real kinetics of the degradation process, leads to the minimum volume and
the ideal behaviour of the lagoon needed to reach the degree of conversion
required to respect the discharge regulations. Because the flow field of a
lagoon is of "shallow waters" type, appropriate technologies have been desi
gned in order to achieve the mixing (by fluidic deviator) and the aeration
(by hydroejector) in such a lagoon. Some applications of these methodologie
s and technologies to industrial problems in the chemical industry (pulp an
d paper) and food industry (sugar) are presented. This original approach is
suitable for modifying existing aerated lagoons, or for upgrading natural
lagoons to aerated lagoons, to successfully meet the new legislat on on eff
luent quality.