The assessment of WWTPs performance: Towards a jigsaw puzzle evaluation?

A chemical and bio-analytical protocol is proposed as a holistic monitoring framework for the assessment
of WWTPs (Wastewater Treatment Plants) performance. This combination of tests consists of: i) an
analysis of emerging contaminants, to be added to the established physicoechemical parameters in order
to understand the causes of (new) pollution phenomena and ii) some of the bio-analytical tools most
widely applied in the field of wastewater research, which provide information on groups of chemicals
with a common mode of toxic action (baseline toxicity, estrogenicity and mutagenicity/genotoxicity,
selected as the most representative for human health). The negative effects of the discharge can thus be
highlighted directly and used to assess the global environmental impact of WWTPs.
As a validation, this multi-tiered approach was applied to a full-scale WWTP (150,000 p.e.), where
different measurements were carried out: EDCs (Endocrine Disrupting Compounds) detection; algal
growth inhibition, bioluminescence inhibition and acute toxicity test (for baseline toxicity); an E-Screenlike
assay (for estrogenic activity); Ames, Allium cepa and Comet tests (for mutagenic/genotoxic activity).
As a result, the WWTP showed good performance for all these issues, displaying its ability to enhance
effluent quality, except for residual mutagenic behaviour, probably due to the by-products generated by
the tertiary ozonation.