In developing countries, as is the case of Brazil, solutions proposed for sewage and sludge treatment and disposal must meet not only public environmental demands and obey proper legal regulations, but also take into account the availability of funds for new investments and operation of existing systems.
Brazilian federal regulations allow ocean disposal of sewage and solids, according to certain water quality criteria and specific standards.
On the other hand, federal regulations require that submarine outfalls must be studied by means of an Environmental Impact Assessment, and that a Report on the Environmental Impact be produced. Such studies must demonstrate that the site will be protected and that ocean disposal will not impair the environment and the beneficial uses, such as fisihing, recreation, navigation, or propagation of marine life.
The State of Rio de Janeiro has monitored its Ipanema Submarine Outfall since 1974, one year prior to going into operation. Present flow is 6m3/sec (140 mgd) of bar-screened domestic sewage. The submarine outfall is a 2.4m diameter concrete pipe, 4.3 km (2.7mi) long, and discharges at a depth of 27m (89ft). The paper presents and discusses existing regulations and data on the seawater monitoring program which is still in practice, having produced more than 90,000 analyses. Discussion covers the period 1974 - 1988, and shows that no adverse ecological impact has been noted on the marine ecosystem.
