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Beaumont-la-Ronce, France

Paing J.,Jean VOISIN SAS | Serdobbel V.,Jean VOISIN SAS | Welschbillig M.,Eau and Industrie | Calvez M.,Eau and Industrie | And 2 more authors.
Water Science and Technology | Year: 2015

This study aimed at determining the treatment performances of a full-scale vertical flow constructed wetlands designed to treat wastewater from a food-processing industry (cookie factory), and to study the influence of the organic loading rate. The full-scale treatment plant was designed with a first vertical stage of 630 m2, a second vertical stage of 473 m2 equipped with a recirculation system and followed by a final horizontal stage of 440 m2. The plant was commissioned in 2011, and was operated at different loading rates during 16 months for the purpose of this study. Treatment performances were determined by 24 hour composite samples. The mean concentration of the raw effluent was 8,548 mg.L-1 chemical oxygen demand (COD), 4,334 mg.L-1 biochemical oxygen demand (BOD5), and 2,069 mg.L-1 suspended solids (SS). Despite low nutrients content with a BOD5/N/P ratio of 100/1.8/0.5, lower than optimum for biological degradation (known as 100/5/1), mean removal performances were very high with 98% for COD, 99% for BOD5 and SS for the two vertical stages. The increasing of the organic load from 50 g.m-2.d-1 COD to 237 g.m-2.d-1 COD (on the first stage) did not affect removal performances. The mean quality of effluent reached French standards (COD < 125 mg.L-1, BOD5 < 25 mg.L-1, SS < 35 mg.L-1). © IWA Publishing 2015. Source

Prigent S.,Jean VOISIN SAS | Prigent S.,Ecole des Mines de Nantes | Paing J.,Jean VOISIN SAS | Andres Y.,Ecole des Mines de Nantes | Chazarenc F.,Ecole des Mines de Nantes
Water Science and Technology | Year: 2013

Upgrades to enhance nitrogen removal were tested in a 2 year old pilot vertical flow constructed wetland in spring and summer periods. The effects of a saturated layer and of recirculation were tested in particular. Two pilots (L = 2 m, W= 1.25 m, H = 1.2 m), filled with expanded schist (Mayennite ®), were designed with hydraulic saturated layers of 20 and 40 cm at the bottom. Each pilot was fed with raw domestic wastewater under field conditions according to a hydraulic load of 15-38 cm d-1(i.e. 158-401 g COD (chemical oxygen demand) mr-2 d-1) and to recirculation rates ranging from 0% up to 150%. The initial load during the first 2 years of operation resulted in an incomplete mineralized accumulated sludge leading to total suspended solids (TSS), COD and biochemical oxygen demand (BOD5) release. A 40 cm hydraulic saturated layer enabled an increase of 5-10% total nitrogen (TN) removal compared to a 20 cm saturated layer. Recirculation allowed the dilution of raw wastewater and enhanced nitrification in a single stage. A design of 1.8 m2 pe -1(48 cm d-1, 191 g COD mr2 d-1) with a 40 cm saturated layer and 100% recirculation enabled the French standard D4 (35 mg TSS L-1,125 mg COD L-1, 25 mg BOD 5L-1), nitrogen concentrations below 20 mg TKN (total Kjeldahl nitrogen) L-1 and 50 mg TN L-1, to be met. © IWA Publishing 2013. Source

Prigent S.,Jean VOISIN SAS | Prigent S.,Ecole des Mines de Nantes | Belbeze G.,Ecole des Mines de Nantes | Paing J.,Jean VOISIN SAS | And 3 more authors.
Ecological Engineering | Year: 2013

The use of compact vertical flow constructed wetlands is becoming increasingly popular in France to treat raw domestic wastewater. This system enables the use of a single deep stage rather than two stages and therefore dramatically reduces the capital costs. A compact vertical flow constructed wetland known as Ecophyltre® was investigated. This system was partially filled with a light expanded schist (Mayennite®) designed to reduce the surface area to 1.2m2pe-1. The aim of this work was to highlight relationships between Mayennite® characteristics with biological activity and treatment performances. After 12 months of operation, the total accumulated dry matter quantity was around 5kgm-2 (20% on the surface). Between 70% and 80% of the microorganisms respiration was principally measured in the top layer of Ecophyltre® during the first year of operation. However, biological activity was shared between the two Mayennite® layers over time. Results showed that Mayennite® retention enabled to kept around 15% water in mass enhancing microorganisms growing. Removal performances of this system met the French standards (35mgTSSl-1; 25mgBODl-1; 125mgCODl-1). © 2012. Source

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