Assessment of the ecotoxicological effects related to the use of natural organic coagulants in the primary treatment of wastewaters at urban and industrial level.
Sabia G., Giuliano A., Farina R.
Articolo Conferenza internazionale con referaggio
Natural coagulants have been receiving much attention in wastewater treatments and sludge conditioning for their eco-friendly and safety characteristics. In this field, the LIFE Adnatur project is aimed at demonstrating the efficacy of new natural based coagulants based on tannin extracted from the Black Acacia bark. Among the products tested in the project, Ecotan Bio 90D was chosen for the evaluation of the potential toxicity effects. Results were compared with a common inorganic metal based coagulant (i.e. FeCl3). The natural coagulant toxicity in aquatic systems was determined by measuring the bioluminescence inhibition of Vibrio fischeri while the potential effects on the biological compartments of a conventional waste water treatment plant were evaluated by estimating the activated sludge activity inhibition by means batch respirometric tests. Moreover, in order to define the coagulant biodegradability, in both aerobic and anaerobic conditions, respirometric techniques and batch test for the assessment of the potential methane production (BMP test) were coupled. BMP tests were carried out on the sludge settled during Jar tests which permitted, by simulating the coagulation/flocculation process, to define the optimal natural coagulant dosage for sludge recovery maximization. The natural coagulant showed to not imply any toxic effects for aquatic life and activated sludge biomass. Moreover the product showed to have a good degree of biodegradability both in aerobic and anaerobic conditions.
Sabia G., Giuliano A., Farina R. ISPRA, Giornate di Studio - 6° edizione. Atti delle giornate di studio su Emergenza Ambiente: l'ecotossicologia come strumento di gestione. Ricerca e applicazione di metodologie ecotossicologiche in ambienti acquatici e matrici contaminate. Pagg. 97-102 Livorno 11-13 novembre 2014