01.CondAmb [020-031] [INGLæS] - Câmara Municipal do Porto

Basic infrastructureMSUQL. ENVIRONMENTAL CONDITIONS.SELECTED INDICATORS•Treated wastewater• Recoverable municipal solid wasteINTERPRETATION OF THE SUBJECTThe existence of a complete and efficient network of basic infrastructure,from water supply to wastewater treatment and to the recoveryof municipal solid waste, is essential to the Quality of Life of a city, both forthe welfare of the population and for environmental reasons.Wastewater treatment is essential in environmental terms since it triesto solve the problem caused by discharges into water courses and the sea, which therefore become morepolluted.The situation has direct negative impact on the environment and on the Quality of Life of a coastal city,depriving the population of these natural spaces.In the city of Porto, and during the period under analysis, there was a tendency for a gradual increase in thepercentage of treated wastewaters. In 2000 (with the opening of the Freixo Wastewater Treatment Plant) only9.3% of the wastewater was treated, whereas in 2002 the percentage increased to 20.8%.At the present moment, the wastewater treatment system is ensured by two Wastewater Treatment Plants.The Freixo WWTP opened in August 2000 and the Sobreiras WWTP in February 2003, together covering thewhole of the city. In the first semester of 2003, 34.5% of the wastewater was treated, but in some months thepercentage was higher than 50%.Another decisive environmental aspect in today’s society concerns the municipal solid waste production andtreatment conditions, since higher production levels require proper treatment of the waste.Traditional solutions such as landfill and composting have been abandoned in favour of separate collectionand resources valorisation, which are unquestionably necessary for the sustainability of a city or region andcontribute to the preservation of natural resources, to the saving of raw material and energy and to thereduction in pollution.This indicator is an estimate ofthe percentage of wastewaterthat is treated in WastewaterTreatment Plants and is calculatedbased on the totalvolume of water billed by SMAS(Water and Sanitation MunicipalServices) and on the volume ofwater that enters the WWTP tobe treated. It is estimated thatonly 80% of the billed waterenters the sanitation system.TREATED WASTEWATERSOURCE: SMAS PORTO(Thousands of m 3 )14,00012,00010,0008,0006,0004,0002,00002nd S.2000 1st S.2001 2nd S.2001 1st S.2002 2nd S.2002 1st S.2003WASTEWATERTREATED WASTEWATER29