Biological and chemical characterizations of the effects of activated sludge sonication
| Autor: | Audrey Prorot, Patrick Leprat, Christophe Dagot, Julien Laurent |
|---|---|
| Přispěvatelé: | Unité de Génétique Moléculaire Animale (UGMA), Université de Limoges (UNILIM)-Institut National de la Recherche Agronomique (INRA), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Institut de Mécanique des Fluides et des Solides (IMFS), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Centre National de la Recherche Scientifique (CNRS), Unité de Génétique Moléculaire Animale (UMR GMA), Institut National de la Recherche Agronomique (INRA)-Université de Limoges (UNILIM) |
| Jazyk: | angličtina |
| Rok vydání: | 2009 |
| Předmět: |
0106 biological sciences
Lysis Sonication Bioengineering 01 natural sciences [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph] 0404 agricultural biotechnology 010608 biotechnology Organic matter [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry Molecular Biology/Biochemistry [q-bio.BM] Molecular Biology chemistry.chemical_classification Chromatography [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph] Chemical oxygen demand 04 agricultural and veterinary sciences General Medicine Biodegradation 040401 food science 6. Clean water [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry Molecular Biology/Biomolecules [q-bio.BM] Activated sludge [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology chemistry [SDE]Environmental Sciences Cell disruption Sewage treatment Biotechnology |
| Zdroj: | New Biotechnology New Biotechnology, Elsevier, 2009, 25 (1), pp.S239. ⟨10.1016/j.nbt.2009.06.228⟩ |
| ISSN: | 1871-6784 1876-4347 |
| DOI: | 10.1016/j.nbt.2009.06.228⟩ |
| Popis: | International audience; Considerable research has been devoted in the past decades to the optimization and control of biological wastewater treatment processes. Many treatment processes have been studied to increase the methane potential of sludge with a rate limiting hydrolysis stage of organic matters associated with microbial cells. Although numerous informations are currently available about sludge minimization processes in WWTP, as sonication, few data are available about its fundamental mechanisms especially microbial changes. In order to clarify the relationship between sludge reduction efficiency and both chemical and biological modifications, the effects of sonication on activated sludge were investigated by combining the monitoring of cell lysis, organic matter solubilization, floc structure and biodegradability. So the aim of this study was to characterize the effects of activated sludge sonication, in terms of cell lysis, organic matter solubilization and biodegradability. For this, in parallel to the organic matter solubilization degree determination (Chemical Oxygen Demand (COD), proteins and sugars), cell disruption in activated sludge was monitored with Flow Cytometry (FCM) before and after sonication. Prior to FCM analyses, activated sludge samples were disaggregated, filtered and stained with a DNA specific fluorescent dye, the Sytox Green, which diffuses only damaged cells. Structural changes during sonication were assessed by microscopic observations and granulometry. Finally, the real impact of thermal treatment on sludge biodegradability was studied under anaerobic conditions. The results showed that, for a specific energy ranging from 0 to 210000 kJ/kg TS, sonication did not induce cell lysis since green fluorescence intensity remained approximately constant before and after sonication. On the contrary, COD, sugars and proteins solubilization degrees reach 27%, 16% and 18% respectively. These results, that showed a progressive release of organic matter particulate components without cell disruption, suggested that the origin of the organic matter released after sonication was only extracellular, probably due to the polymeric network disruption. Moreover, the results from anaerobic biodegradability tests did not show any improvement after sonication, indicating that the specific energy was not high enough to increase anaerobic biodegradability of the sludge. Even if sonication induced a progressive release of organic matter components from particulate to soluble fraction, the specific energy applied was not high enough to induce cell lysis, and consequently, anaerobic biodegradability improvement. Moreover, this study showed that hydrolysis treatments improvement requires a precise knowledge of both biological and chemical changes induced during hydrolysis processes. |
| Databáze: | OpenAIRE |
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