Priority and emergent contaminants in municipal wastewaters: levels and removal in WWTPs
Presenta: Valeria Mezzanotte
DISAT, Università degli Studi di Milano Bicocca
Priority and emergent pollutants (EPs) include a wide range of elements (chiefly heavy metals) and organic molecules. For many of them the toxicity is well known, but still no limit exists for the discharge, even if, in some cases, water quality standards have been enforced at national and international level. The presence and amount of EPs in wastewater depends on various sources, some of which are specific while others are common to different families of compounds. Among the main sources are excretion and disposal for pharmaceutical compounds, direct discharge, use and disposal for industrial products and pesticides, generation by combustion and soil deposition and run-off for PAH, etc.
The efficiency of conventional wastewater treatment plants (WWTPs) in removing EPs is highly variable and mostly unreliable. Due to the differences among EPs and process efficiencies, and to the concurrent presence of many of them, reliable performances can just be obtained by combining more than one tertiary treatment. Considering the costs related to the upgrade of conventional WWTPs for EP removal, interventions on the drainage systems and sewer overflows should also be considered and the true need for advanced treatments should be evaluated with respect to the flow and conditions of the receiving waters.
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