ESTUDO DAS CONDIÇõES SANITARIAS DA REPRÊSA BILLINGS

Abstract

Billings reservoir, located about 746.5 m over the sea, near the city of S. Paulo, Brazil covers an area of approximately ......... .127,000,000 sqm. It was built for the production of hidroelectric power and it is feeded by very polluted waters which receive the non-treated sewage from the city. In the places located near the pumping dam (until about 1,000 m far) the conditions are pemanently septic but a great self-depuration capacity can be observed. This self-depuration capacity promotes the re-establishment of the water qualities in the first quarter of the resorvoir area. This report analyse Billings reservoir from two points o f view: 1) Regarding the use o f some o f its branches in water supply through new dams; 2) Regarding the self-depuration capacity for the final stabilization of primary treated sewage effluents, which seems to be due mainly to the photosynthetic activity of massive growth of algae (specially Microcystis aeruginosa). However, the introduction of non-treated sewage decreases the power of stabilization that would be increased hy a primary treatment. New methods for future research to determine the phytoplanctonic oxygen production (using dark and transparent bottles), chlorophyl concentration and subsurface currents, as well as studies concerning the influence of mud anrl algae respiration on ROD concentration are suggested.