Phytoplankton in Polishing Ponds in the Post Treatment of Anaerobic Reactor Effluent

Considering the variable a indicative of the trophic state of aquatic environments and a useful tool in the evaluation of the impact of organic and inorganic contaminants, this work aimed to verify the occurrence and frequency of the phytoplankton community in continuous and semi-continuousflow polishing lagoons used in post-treatment of effluents from anaerobic reactors. The research was carried out at the Experimental Station of Biological Treatment of Sanitary Sewers (EXTRABES). The system consisted of an Upflow Anaerobic Sludge Blanket (UASB), an equalization tank and the transshipment pond responsible for feeding the four ponds. There were identified twenty-five taxa distribuited in five taxonomic classes: cyanobacteria (7 taxa), Chlorophyceae (5 taxa), Bacillariophyceae (4 taxa), Euglenophyceae (2 taxa) and Zygnemaphyceae (2 taxa). The predominance of Chlorophyceae was observed, which was constant in the four lagoons of the system, followed by Cyanobacteria, Euglenophyceae, Bacillariophyceae and Zignemaphyceae. Based on the composition of the species of cyanobacteria that were found, they present histories in the production of metabolites and are described in the literature as the producers of toxins harmful to humans and to the environment.