The last ten seminars:

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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Model approaches to the study and management of lake ecosystems: past experiences and future perspectives of research

Presenta: Diego Copetti

CNR IRSA Sede di Brugherio

Lake are complex systems characterized by the interplay of physical, chemical and biological processes. The physical forcing in particular determines the degree of mixing of the water masses that in turn influences the distribution of both chemical and biological species. Coupled hydrodynamic-ecological models integrate the description of both physical and chemical-biological processes and they can be thus important tools for the study and the management of lacustrine environments. In recent years, the scientific community also developed open-source lake models, such as the one-dimensional General Lake Model (GLM) implemented within GLEON (Global Lake Ecological Observatory Network) with the main goal to integrate model simulations and real time measurements. One-dimensional models are "economical" computational solutions that simplify the system to the processes occurring on the vertical neglecting those occurring on the horizontal direction. Originally, these models were designed to study the dynamics of small or mid-sized lakes and resulted particularly efficient in long-term simulations (e.g. climate change impact studies). Recent researches demonstrated the applicability of one-dimensional models even to large and deep environments such as the deep south-alpine lakes. Different studies curried out in these environments however underlined a marked spatial heterogeneity induced by different physical features such as: complex morphometry, inflow intrusions and differential wind action. Such a spatial heterogeneity can be captured only using more complex models such as three-dimensional ones. These tools nevertheless present the disadvantages to be much more time consuming and computational demanding. In this seminar previous experiences and current research on the use of coupled hydrodynamic-ecological models to Lake Pusiano and Como case studies will be presented and discussed.

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biomonitoR: an R package for calculating biomonitoring indices of running waters

Presenta: Alex Laini

Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma

Biomonitoring is crucial to assess and preserve the quality status of running waters. Following the implementation of Water Framework Directive, a multitude of indices has been developed targeting at the effects of different stressors on aquatic communities. However, the application of those indices is generally confined within the country in which they are developed, making the sharing of methods among researchers difficult. Our work aims to cover this gap by developing a package called biomonitoR for the free statistical software R.
The indices developed until now encompass different features of biotic communities such as diversity and evenness, sensitivity to stressors and functional indices based on fuzzy-coded biological and ecological traits. biomonitoR is still in development but is already downloadable (https://github.com/alexology/biomonitoR/) and testable. This project it is based upon work from COST Action CA15113 (SMIRES, Science and Management of Intermittent Rivers and Ephemeral Streams, www.smires.eu) supported by COST (European Cooperation in Science and Technology).

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Fasce riparie, habitat e ritenzione dei nutrienti. Potenzialità per la gestione delle acque nei sistemi agrourbani

Presenta: Raffaella Balestrini

Istituto di Ricerca sulle Acque-CNR, Brugherio (MB)

Dati recenti sullo stato delle acque superficiali in Europa rivelano che oltre la metà dei fiumi monitorati non raggiungono lo stato ecologico "buono". Tra le pressioni principali, l'inquinamento diffuso derivante dalle pratiche agricole causa l'arricchimento di nutrienti e l'alterazione degli habitat fluviali. La concentrazione di nitrato nei corpi idrici europei è diminuito solo di circa il 12% nell'ultimo ventennio e gli scenari futuri indicano che la diminuzione dei carichi fluviali di azoto (N) e fosforo (P) che si prevede di raggiungere nel 2050 sarà insufficiente a evitare il rischio di bloom algali nelle acque costiere. Con l'obiettivo di sviluppare efficaci misure di mitigazione, molta attenzione è stata rivolta ai processi biogeochimici che avvengono naturalmente in porzioni dell'ecosistema fluviale e/o direttamente in alveo in grado di attenuare le concentrazioni dei nutrienti esportati a valle. Le fasce riparie, localizzate all'interfaccia tra ecosistema acquatico e terrestre, rappresentano un sistema tampone in grado di attenuare i carichi di contaminanti in ingresso nelle acque superficiali e sotterranee. I principali meccanismi biologici in grado di ridurre la contaminazione da nitrato sono l'assimilazione da parte delle comunità biologiche e la denitrificazione che rimuove definitivamente il nitrato trasformandolo in azoto molecolare gassoso. Diversi studi hanno altresì dimostrato che i processi che avvengono all'interno dell'alveo fluviali (processi "in-stream") possono condizionare in modo significativo il trasporto dei nutrienti a valle, soprattutto nei corpi idrici di piccole dimensione. In questo ambito verranno illustrate le metodologie applicate e i principali risultati ottenuti grazie a ricerche condotte nel reticolo idrografico minore della Pianura Padana. Gli obiettivi finali sono volti a fornire degli strumenti gestionali per la protezione e/o il risanamento dei sistemi fluviali in un'ottica di salvaguardia dei servizi ecosistemici offerti dall'intero bacino idrografico.

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