[1] Inst Politecn Porto, Inst Super Engn Porto, REQUIMTE LAQV, Rua Dr Antonio Bernardino Almeida 431, P-4200072 Porto, Portugal
[2] Aguas Ctr Litoral SA, Grp Aguas Portugal, ETA Boavista, Ave Dr Luis Albuquerque, P-3030410 Coimbra, Portugal
[3] Aguas Douro & Paiva SA, Grp Aguas Portugal, Rua Vilar 235 5, P-4050626 Porto, Portugal
[4] Inst Politecn Porto, Inst Super Engn Porto, Dept Engn Civil, Rua Dr Antonio Bernardino de Almeida 431, P-4200072 Oporto, Portugal