Reviving käthe seidel’s legacy to University of Minho

Abstract

In the 80’s Prof. Käthe Seidel was in Portugal by invitation of the University of Minho (UM). The relationship established led to the donation of Seidel’s laboratory to UM, to create a Limnological Laboratory. Some institutional and personal reasons rendered this unviable and until now, Seidel’s legacy at UM is resumed to some German bibliography, equipment and unpublished work. Prof. Kickuth was Seidels’ disciple. His technology is based on a rooted emergent macrophyte system of horizontal subsurface flow that relied on optimized substrate planted with Phragmites. Aiming to determine the efficiency of Kickuth’s process and to understand the role of the biotic communities presented on these optimized substrates, mensal sampling campaigns were made in a Constructed Wetland (CW) located in the North of Portugal. The sampling campaigns began on January 2005. Inlet (IN) and outlet (OUT) wastewater simple samples and substrate samples were taken from one of the two CW’s beds. In situ determinations of temperature, pH and redox potential were recorded, and IN and OUT wastewater samples were analysed for BOD5, COD and TSS; estimated densities of some microbiological communities were assessed by the recovery of colony formed units (CFU/ml) on solid culture media, using the spread technique. The results obtained show a very good efficiency on organic load removal (values of 80-90%) accompanied by higher values in percent removal of the estimated heterotrofics CFU/ml. The total and fecal coliforms removal was also high (90-100%). The substrate’s biodiversity characterized by optical microscopy allowed the identification of both protozoa and metazoa (mainly nematodes and annelids). The sampling and quantification methodologies of the biota taxa aren’t optimized. As the knowledge of this “black box” effective function may contribute to increase the credibility of these sustainable systems, it seems pertinent to proceed with these studies.