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The goal of this study is to examine the suitability of three plants, Typha spp., Phragmites spp. and Iris pseudacorus, in a free water surface constructed wetland created to treat eutrophic water from Lake Albufera (Valencia, Spain), a wetland of international importance. The growth, coverage and nutrient content of the three plants were studied, and chemical analyses were performed according to standard methods. The maximum standing crops measured for each plant were 1.9, 18.2 and 3.3 kg m , respectively, and their average nutrient concentrations were 2.1, 1.2 and 1.7 g P kg and 12.1, 11.7 and 10.1 g N kg , respectively. A multiple harvest of Iris pseudacorus revealed that the removal of nutrients could be increased up to 50% for N and 100% for P compared with a single harvest. Biomass decomposition assays showed high values for five day biochemical oxygen demand (115-207 mg O g , depending on the plant and its age) and a substantial release of phosphorus, up to 100% of that contained in the biomass, highlighting

Eutrophication is a widespread problem that is being tackled from many perspectives and the recently applied technology of constructed wetlands is being used in the treatment of eutrophic water. However, process-based models to simulate their performance are scarce, so in this work a mechanistic model was developed to simulate the removal of total suspended solids, phytoplankton and total phosphorus in free water surface constructed wetlands treating eutrophic water. The model represents the influence of the main factors of the biotope and biota on these water quality variables, and particular attention is paid to resuspension produced by wind and by avifauna. Likewise, the effect of emergent vegetation cover in sedimentation, resuspension and phytoplankton growth is included. Phytoplankton is considered to store phosphorus internally in order to use it when growing, and the contribution of phytoplankton concentration to the suspended solids budget is included. The software AQUASIM was used to calibrate and validate the model in two full-scale constructed wetlands treating eutrophic water from Lake l´Albufera de València (Spain) for three years. The simulated data and field measurements showed satisfactory adjustments for the three studied variables. The budgets obtained for each variable reveal that sedimentation and resuspension are the main processes in total suspended solids performance. Sedimentation of organic particulate phosphorus is the most important process in total phosphorus removal. The sum of the effect of resuspension by avifauna and by wind increases by more than 50% the quantity of solids that enters the water column. The model reveals that simulating the effects of the emergent vegetation cover and resuspension is crucial for representing the performance of the studied variables.

Three medium size constructed wetlands (CWs) with a total surface of 90ha are working since 2009 in the Albufera de Valencia Natural Park (Spain). Two of them are fed with eutrophic waters from l'Albufera Lake. Their objectives are both reduce the phytoplankton biomass and increase the biodiversity; consequently, improved water quality is returned to the lake. A "science based governance" of these CWs is ongoing inside the LIFE+12 Albufera Project to demonstrate the environmental benefits of these features. In this paper, results and relationships among hydraulic operation, physicochemical variables and plankton in two different CWs typologies, five free water surface CW (FWSCW) and one horizontal subsurface flow CW (HSSFCW), were analysed showing that CWs were capable of improving the water quality and biodiversity but showing clear differences depending on the CW type. The CWs worked under different hydraulic load rates (HLR) from <0.12 to 54.75myr. Inflow water quality was typical from eutrophic waters with mean values of chlorophyll a (Chl a) about 22-90μgChlal and mean total phosphorus (TP) between 0.122 and 0.337mgl. The main conclusion is that HSSFCW was much more efficient than FWSCW in the removal of organic matter, suspended solids and nutrients. The biological role of several shallow lagoons located at the end of the CWs has also been evaluated, showing that they contribute to increase the zooplankton biomass, a key factor to control the phytoplankton blooms.