EFFLUENT OF SEWAGE TREATMENT FACILITY: EFFECTS ON WATER QUALITY OF A SMALL STREAM

Sewage treatment facilities are considered as positive measures regarding the water quality of rivers that receive the treated effluent. The present study reports the effect of the effluent discharge on the electrical conductivity (EC), dissolved organic carbon (DOC) and dissolved oxygen ( DO) of the Piracimirim Stream located in Piracicaba, Sao Paulo State, Brazil. For both, two sampling points were established in upstream and downstream relative to the effluent discharge point. By comparing these two points, it is shown that EC as well as DOC presented a significant increase. These findings were different from those ones made 10 years earlier for the same stream and they may indicate the decline of treatment station efficiency.