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Tora J.A.,Autonomous University of Barcelona | Moline E.,Depuracion de Aguas del Mediterraneo DAM | Carrera J.,Autonomous University of Barcelona | Perez J.,Autonomous University of Barcelona
Chemical Engineering Journal | Year: 2013

An automated sequencing batch reactor operation based on online measurement of the ammonium concentration was investigated as a tool for improving the start-up of a nitrifying granular airlift reactor. The effectiveness of this start-up procedure was verified with the characteristics of the developed granular sludge but also the improvement of the start-up was confirmed when comparing with the results achieved with two continuous-mode start-up strategies. Once a stable granular biomass was obtained, the reactor started to operate in continuous mode during more than 100days, maintaining the characteristics of the granular biomass and achieving a nitrogen loading rate of 1.75gNL-1d-1. The intermittent recirculation of small flocs of nitrifying biomass was explored as an alternative to increase the biomass concentration in the reactor and consequently, to increase the treated loading rate. © 2013 Elsevier B.V.

Pijuan M.,Catalan Institute for Water Research | Tora J.,Autonomous University of Barcelona | Rodriguez-Caballero A.,Catalan Institute for Water Research | Cesar E.,Depuracion de Aguas del Mediterraneo DAM | And 2 more authors.
Water Research | Year: 2013

Nitrous oxide (N2O) and methane emissions were monitored in a continuous granular airlift nitritation reactor from ammonium-rich wastewater (reject wastewater). N2O emissions were found to be dependent on dissolved oxygen (DO) concentration in the range of 1-4.5mgO2/L, increasing within this range when reducing the DO values. At higher DO concentrations, N2O emissions remained constant at 2.2% of the N oxidized to nitrite, suggesting two different mechanisms behind N2O production, one dependent and one independent of DO concentration. Changes on ammonium, nitrite, free ammonia and free nitrous acid concentrations did not have an effect on N2O emissions within the concentration range tested. When operating the reactor in a sequencing batch mode under high DO concentration (>5mgO2/L), N2O emissions increased one order of magnitude reaching values of 19.3±7.5% of the N oxidized. Moreover, CH4 emissions detected were due to the stripping of the soluble CH4 that remained dissolved in the reject wastewater after anaerobic digestion. Finally, an economical and carbon footprint assessment of a theoretical scaled up of the pilot plant was conducted. © 2013 Elsevier Ltd.

Sevilla E.L.,CSIC - Center of Edafology and Applied Biology of the Segura | Garcia M.J.S.,CSIC - Center of Edafology and Applied Biology of the Segura | Pascual Valero J.A.,CSIC - Center of Edafology and Applied Biology of the Segura | Andreu P.S.,Entidad de Saneamiento de la Region de Murcia Esamur | And 4 more authors.
Tecnologia del Agua | Year: 2011

Aware of the necessity of the up-dating, stabilization and sanitation of sludge with the aim of achieving the parameters established in the 'Proposal for a Directive of the European Parliament and of the Council on spreading of sludge on land', the authors have installed in the WWTP of Molina de Segura a pilot digestor with an advanced system known as Termophilic Anaerobic Digestion (TAnD), consisting of the thermophilic anaerobic digestion of the sludge. The aims of this work consist of the start-up of the pilot plant, its monitoring and its optimization while developing a comparative study with the conventional anaerobic mesophilic digestion system set up in this WWTP, and mainly of the monitoring of the human pathogens provided in the proposal for a future directive.

Pascual A.,Research Center y Desarrollo Tecnologico | Fuerte B.R.,Research Center y Desarrollo Tecnologico | Forner L.R.,Depuracion de Aguas del Mediterraneo DAM | Alcaniz L.P.,Depuracion de Aguas del Mediterraneo DAM
Tecnologia del Agua | Year: 2012

The co-digestion of substrates is a feasible alternative to increase the production of biogas in wastewater treatment plants (WWTP). This method aims to correct the imbalance between nutrients, to increase the concentration of organic matter in the digester and to dilute potential inhibitors what would improve the biogas production. The objectives of the study, conducted at the WWTP Pobla de Farnals, were the identification and characterization of potential co-substrates in the area, the determination of the maximum biogas yield of these co-substrates and the formulation of the appropriate mixture. Previous to the introduction of the chosen substrate in the digester a simulation in a pilot plant was conducted.

Marques F.,Depuracion de Aguas del Mediterraneo DAM | Pradas P.,Depuracion de Aguas del Mediterraneo DAM | Lardin C.,Entidad de Saneamiento | Simon P.,Entidad de Saneamiento
Tecnologia del Agua | Year: 2010

This paper reports the results obtained when a sludge age based control is incorporated in the biological process of a wastewater treatment plant (WWTP). Greater stability of the biological process is achieved when this control is implemented in WWTP of Molina de Segura. In particular biodiversity has increased and it has been possible to reduce and stabilize the secondary sludge production. An improvement of the sludge décantation and a reduction of the specific volumetric load of secondary clarifiers have also been observed. Finally, costs have been reduced due to the decrease of cationic polyelectrolyte consumption.

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