Title: Abatement efficiency of municipal wastewater treatment plants using different technologies (Orbetello Lagoon, Italy)

Authors: Monia Renzi, Guido Perra, Cristiana Guerranti, Enrica Franchi, Silvia Focardi

Addresses: Research Centre of Lagoon Ecology, Fishery and Aquaculture, University of Siena, Polo Universitario Grossetano, via lungolago dei pescatori, SN, 58015, Orbetello (GR), Italy; Department of Environmental Science, University of Siena, via Mattioli 4, 53100 Siena, Italy. ' Department of Environmental Science, University of Siena, via Mattioli 4, 53100 Siena, Italy. ' Department of Environmental Science, University of Siena, via Mattioli 4, 53100 Siena, Italy. ' Research Centre of Lagoon Ecology, Fishery and Aquaculture, University of Siena, Polo Universitario Grossetano, via lungolago dei pescatori, SN, 58015, Orbetello (GR), Italy. ' Department of Chemical and Biosystems Sciences, University of Siena, via Aldo Moro 1, 53100 Siena, Italy

Abstract: Two small-scale municipal wastewater treatment plants (Neghelli and Terrarossa) discharging effluents into a lagoon of great environmental interest and highly stressed by tourism (Orbetello, Italy) were monitored over the year 2001. We evaluated plants| performances developing a general efficiency indicator of removal to select the suitable purification technology (activated sludge, Neghelli vs. rotating biodisc reactor, Terrarossa). Unexpected, conventional technologies (activated sludge) had best performances (84% vs. 62%) with higher removal efficiencies for dissolved nutrients producing, on average, better final effluents. Even if Terrarossa showed a great improvement in summertime, during winter it seemed to be considerably affected by sea aerosol. Before the final discharge in lagoon, effluents were phytodepurated in a pond to reduce their nutrient load. Although data showed that the pond had further abatement efficiency over 80%, final outlet water represented a dangerous input for the lagoon ecosystem.

Keywords: MWWTPs; municipal wastewater treatment plants; Italy; abatement efficiency; Orbetello Lagoon; nutrients; PDP; phytodepuration pond; Central Tyrrhenian Sea; effluent monitoring; lagoon ecosystems; water quality; water pollution.

DOI: 10.1504/IJENVH.2009.022905

International Journal of Environment and Health, 2009 Vol.3 No.1, pp.58 - 70

Published online: 02 Feb 2009 *

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