Monitorização de desempenho da ETAR da Mutela no contexto de acções de controlo de microrganismos filamentosos nos tanques de arejamento

Carina Andreia da Costa Cruz Afonso

Key information

Authors:

Carina Andreia da Costa Cruz Afonso (Carina Andreia da Costa Cruz Afonso Nunes)

Supervisors:

Nídia Lourenço de Almeida (Laboratório de Tecnologias Ambientais Ceqb - Ist) (Nídia Lourenço de Almeida (Laboratório de Tecnologias Ambientais Ceqb - Ist)); Helena Maria Rodrigues Vasconcelos Pinheiro (Helena Maria Rodrigues Vasconcelos Pinheiro)

Published in

11/25/2011

Abstract

From April to September 2011, populations of protozoa and filamentous bacteria present in the aeration tanks of the wastewater treatment plant of Mutela (Almada) were studied. Spectroscopic analysis was performed on samples in the liquid phase of the treatment process, and the acquired spectra were subsequently studied using Principal Components Analysis. The main objective was to find correlations between the microscopic observations, the spectrophotometric analysis, and the operating status of the WWTP. There was a large variability in protozoa populations in the aerations tanks, the predominant types varying over the study monthsThe dominant filamentous bacteria detected were Nocardia, Nostocoida I and type 1863. A relation between the dominant filamentous bacteria and the type and amount of foam in the aeration tanks was found and confirmed. The storage stability of liquid samples was tested, giving the conclusion that a spectrum of a fresh sample is completely different from that of the same sample stored for 4-5 hours at room temperature. Therefore, in order to be able to correlate the spectroscopic analysis with the analytical parameters it is crucial to use fresh samples in the spectral analysis. PCA made it possible to identify spectra that corresponded to days when there were problems in the treatment process. They also confirmed that, despite the quality variability in the wastewater at the plant?s entrance, at the exit there is very little quality variation. The treatment plant of Mutela, showed treatment robustness, consistently meeting the quality objectives and thus producing a final effluent of good quality.