MICROBIAL COMMUNITY ANALYSIS OF ETHOXYLATED NONYL PHENOL DEGRADING MICROCOSMS AND ACTIVATED SLUDGE SYSTEMS

ITRIA, RAÚL F.; LOZADA, MARIANA; DE TULLIO, LUIS; ERIJMAN, LEONARDO

Córdoba, Argentina

Congreso; Congreso de la Sociedad Argentina de Investigaciones Bioquímicas (SAIB); 2001

Sociedad Argentina de Investigaciones Bioquímicas

Nonyl phenol elhoxylates (NPEO) are non-ionic surfactants widely used for a variety of industrial processes. Primary degradation of NPEO in wastewater treatment plants (WWTP) or directly in aquatic environments in areas where there is no sewage or industrial waste treatment, leads to lhe formation of relatively hydrophobic compounds such as nonylphenol (NP), that disrupt endocrine function and sexual development in aquatic organisms at low concentrations. Sludge from a full-scale activated sludge treatment plant was used lo establish two experimental set-ups representing model ecosystems: a microcosm with limited nutrient available, and a laboratory scale semi-continuous aclivated sludge treatment plant (SCAS). Both systems were periodically fed with 0.1 %, (w/v) NPEO (plus synthetic wastewater for SCAS). Shifts in microbial population due to changes in the activity of the community in response to increasing concentration of NPEOx degradation intermediates were determined by phase contrast microscopy and methods based on the phylogenetic framework given by the 16S rRNA sequences. Increasing organic matter removal efficiency (measured as chemical oxygen demand reduction) revealed acclimatization ofthe SCAS community lo the surfactant. However, biomass growth was negligible respect to controls. Thinlayer chromatography with specific detection for NPEO homologs and for phenols revealed significant degradation intermediates accumulate in microcosms.