Monitorização da unidade de lamas activadas da ETAR da Mutela por análise da população microbiana e espectroscopia UV-visível

Mário Daniel Abreu e Silva

Key information

Authors:

Mário Daniel Abreu e Silva (Mário Daniel Abreu e Silva Freire)

Supervisors:

Ana Cristina Furtado (Ana Cristina Furtado); Helena Maria Rodrigues Vasconcelos Pinheiro (Helena Maria Rodrigues Vasconcelos Pinheiro)

Published in

12/09/2010

Abstract

This work goal was to find relations between microscopic observations (protozoa and filamentous bacteria in bioreactors), operational control strategies adopted, values of laboratory daily results, and UV-Visible spectrums from liquid samples, from April to September 2010, in the wastewater treatment plant (WTP) of Mutela (Almada). Sludge Biotic Index (SBI) values were always high (8-9), corroborating the values of the removal efficiency of COD and BOD5, indicating efficient biological treatment in the WTP throughout the study. 6 species of filamentous bacteria were observed and identified, 3 of them dominant (Nocardia spp., 021N and 1863). The first one is known to cause ?bulking? and ?foaming? problems, so a full series of control strategies were adopted. A direct relation was found, between the dominant filamentous specie, and the color and amount of sludge in the aeration tanks. The WTP presented sludge sedimentation issues, strengthened by high values of Sludge Volumetric Index (SVI), which was put to a minimum during the control strategy involving sludge recirculation to the biological tanks stoppage from 23-7 h, leading to better sludge sedimentation (reducing the abundance of Nocardia spp.). Two attempts were made to use bio-supplementation using commercial products, which proved insufficient improving sludge sedimentation. The WTP of Mutela, possesses, a robust treatment system, because despite the implementation of several control strategies, changing dominant filamentous specie, the levels of organic matter removal kept high, fulfilling the WTP quality standards established.