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Main Author:	María Casamitjanaa Causa
Format:	Artículo científico
Language:	en
Published:	Escuela de Ingeniería de Antioquia 2015
Subjects:	Ingeniería Wastewater Filterability Nutrient removal Membrane Bioreactor Sludge Recirculation
Online Access:	https://www.redalyc.org/articulo.oa?id=149240052007
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author	María Casamitjanaa Causa
author_facet	María Casamitjanaa Causa
contents	INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS María Casamitjanaa Causa Ignasi Rodríguez Roda Layret Monserrat Dalmau Figueras Ingeniería Wastewater Filterability Nutrient removal Membrane Bioreactor Sludge Recirculation Membrane bioreactors (MBR) technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor), anoxic recirculation (from the aerobic to the anoxic reactor) and anaerobic recirculation (from the anoxic to the anaerobic reactor)]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST) remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP), which seems to depend on external and anoxic sludge recirculation. 2015 artículo científico 1794-1237 https://www.redalyc.org/articulo.oa?id=149240052007 en http://www.redalyc.org/revista.oa?id=1492 Revista EIA application/pdf Escuela de Ingeniería de Antioquia Revista EIA (Colombia) Num.2 Vol.12
format	Artículo científico
id	redalyc_149240052007
language	en
publishDate	2015
publisher	Escuela de Ingeniería de Antioquia
spellingShingle	INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS María Casamitjanaa Causa Ingeniería Wastewater Filterability Nutrient removal Membrane Bioreactor Sludge Recirculation INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS María Casamitjanaa Causa Ignasi Rodríguez Roda Layret Monserrat Dalmau Figueras Ingeniería Wastewater Filterability Nutrient removal Membrane Bioreactor Sludge Recirculation Membrane bioreactors (MBR) technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor), anoxic recirculation (from the aerobic to the anoxic reactor) and anaerobic recirculation (from the anoxic to the anaerobic reactor)]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST) remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP), which seems to depend on external and anoxic sludge recirculation. 2015 artículo científico 1794-1237 https://www.redalyc.org/articulo.oa?id=149240052007 en http://www.redalyc.org/revista.oa?id=1492 Revista EIA application/pdf Escuela de Ingeniería de Antioquia Revista EIA (Colombia) Num.2 Vol.12
title	INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS
topic	Ingeniería Wastewater Filterability Nutrient removal Membrane Bioreactor Sludge Recirculation
url	https://www.redalyc.org/articulo.oa?id=149240052007

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// Anecdotal testing Today and Yesterday seems to indicate destroy() // is called by the garbage collector and everything is good. // Something to keep in mind though. return 0; } /** * Write function that is called when session data is to be saved. * * @param string $sessId The current session ID * @param string $data The session data to write * * @return bool */ public function write($sessId, $data): bool { if ($this->writesDisabled) { return true; } return $this->saveSession($sessId, $data); } /** * A function that is called internally when session data is to be saved. * * @param string $sessId The current session ID * @param string $data The session data to write * * @return bool */ abstract protected function saveSession($sessId, $data): bool; }

* * @return void */ public function writeClose() { // The assumption is that we're using PHP's ext/session. // session_write_close() will actually overwrite $_SESSION with an // empty array on completion -- which leads to a mismatch between what // is in the storage object and $_SESSION. To get around this, we // temporarily reset $_SESSION to an array, and then re-link it to // the storage object. // // Additionally, while you _can_ write to $_SESSION following a // session_write_close() operation, no changes made to it will be // flushed to the session handler. As such, we now mark the storage // object isImmutable. $storage = $this->getStorage(); if (! $storage->isImmutable()) { $_SESSION = $storage->toArray(true); session_write_close(); $storage->fromArray($_SESSION); $storage->markImmutable(); } } /** * Attempt to set the session name * * If the session has already been started, or if the name provided fails * validation, an exception will be raised. * * @param string $name * @return SessionManager * @throws Exception\InvalidArgumentException */ public function setName($name) { if ($this->sessionExists()) { throw new Exception\InvalidArgumentException( 'Cannot set session name after a session has already started'

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