2014-12-042014-12-042014-10-30D’ALESSANDRO, Emmanuel Bezerra; SAAVEDRA, Nora Kátia; SANTIAGO, Mariângela Fontes; SILVA, Maura Francisca da. Dinâmica e sazonalidade das variáveis físico-químicas e biológicas de uma lagoa facultativa. Revista Eletrônica de Engenharia Civil, Goiânia, v. 9, n. 2, p. 1-23, out. 2014. Disponível em: < http://www.revistas.ufg.br/index.php/reec/article/view/29447/17156>.e- 2179-0612http://repositorio.bc.ufg.br/handle/ri/4506v. 9, n.2, p. 10-23, out. 2014.This research had as main objective to investigate the involved processes in facultative pond efficiency of A module in Trindade WWTP, a period of six months with seasonal differences. The samples were collected at inlet and outlet of pond, also on the surface, at different depths. Studies of profile were made from physicochemical and biological variables. It was also made a principal component analysis, to verify the efficiency of BOD and nutrients removal by phytoplankton. The pond showed undergoes influence by seasonality of region. It was recorded DO profile of type clinograde, and thermal stratification in three months of collect. In two consecutive periods, were registered very low concentrations of DO (<1.0 mg.L1 ). The principal component analysis showed that variations of the phytoplankton community had a direct influence of pH, CND, and possibly with HDT. This process was correlated with removal efficiency of BOD (r=0.85) and orthophosphate (r=0.98). The ammonia removal was associated with temperature.porAcesso abertoTratamento de esgotoFitoplânctonRemoção de nutrientesLagoa facultativaNutrients removalPhytoplanktonWastewater treatmentFacultative pondArtigoD.O.I. 10.5216/reec.V9i2.29447