Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study

Autores
Caravelli, Alejandro Horacio; Giannuzzi, Leda; Zaritzky, Noemí Elisabet
Año de publicación
2006
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Chlorination is a very useful control method of filamentous bulking in activated sludge systems; however, it favours formation; of undesirable compounds such as trihalomethanes. Other oxidants, such as ozone, could be used for bulking control. In view of the fact that chlorine and ozone are both non-selective chemical agents affecting filamentous and floc-forming micro-organisms, the determination of optimum dosage conditions becomes essential to minimise the impact produced on the activated sludge process. In this work, the effects of chlorine and ozone on the biomass concentration of activated sludge and on different parameters that characterise the microbial metabolic activity were compared. The following techniques were applied: Respirometry (oxygen uptake rate); and INT-dehydrogenase activity test carried out both by spectrophotometry (DHAa) and image analysis (DHAi). The respirometric technique and the DHAa test quantified oxidants action on the total respiratory activity of flocs; the image DHAi test was applied to evaluate the specific action of the oxidants on filamentous micro-organisms. Additionally, plate count technique, respirometry and DHAa test were correlated using chlorine and ozone experiments on pure cultures of a floc-forming micro-organism (Acinetobacter anitratus) to compare the effect of the oxidising; agents on the metabolic activity and the viability of the micro-organisms. Ozone was found to have more intense antimicrobial action. In activated sludge, ozone reduced total biomass concentration by oxidising various components and causing cell lysis. An equation was proposed to estimate biomass concentration of activated sludge as a function of time and ozone dose rate; in contrast, at the doses applied, chlorine did not reduce the concentration of activated sludge biomass. In activated sludge, adequate conditions for both oxidants were identified under which the respiratory activity of filamentous micro-organisms could be considerably inhibited, causing the lowest possible impact on whole floc metabolic activity. An initial chlorine dose of 7.9 mgCl2·gVSS-1 for a contact time of 5 min (initial pulse= 6.0 mgCl2·l-1), and a total ozone dose of 66.0 mgO3·gVSS-1 (ozone dose rate of 3.3 mgO3·gVSS-1·min-1 for a contact time of 20 min) were the most suitable conditions to control filamentous bulking.
Centro de Investigación y Desarrollo en Criotecnología de Alimentos
Materia
Química
Filamentous bulking
Chlorine
Ozone
INT-dehydrogenase activity
Respirometry
Image analysis
Late count
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/128235

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network_name_str SEDICI (UNLP)
spelling Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative studyCaravelli, Alejandro HoracioGiannuzzi, LedaZaritzky, Noemí ElisabetQuímicaFilamentous bulkingChlorineOzoneINT-dehydrogenase activityRespirometryImage analysisLate countChlorination is a very useful control method of filamentous bulking in activated sludge systems; however, it favours formation; of undesirable compounds such as trihalomethanes. Other oxidants, such as ozone, could be used for bulking control. In view of the fact that chlorine and ozone are both non-selective chemical agents affecting filamentous and floc-forming micro-organisms, the determination of optimum dosage conditions becomes essential to minimise the impact produced on the activated sludge process. In this work, the effects of chlorine and ozone on the biomass concentration of activated sludge and on different parameters that characterise the microbial metabolic activity were compared. The following techniques were applied: Respirometry (oxygen uptake rate); and INT-dehydrogenase activity test carried out both by spectrophotometry (DHAa) and image analysis (DHAi). The respirometric technique and the DHAa test quantified oxidants action on the total respiratory activity of flocs; the image DHAi test was applied to evaluate the specific action of the oxidants on filamentous micro-organisms. Additionally, plate count technique, respirometry and DHAa test were correlated using chlorine and ozone experiments on pure cultures of a floc-forming micro-organism (Acinetobacter anitratus) to compare the effect of the oxidising; agents on the metabolic activity and the viability of the micro-organisms. Ozone was found to have more intense antimicrobial action. In activated sludge, ozone reduced total biomass concentration by oxidising various components and causing cell lysis. An equation was proposed to estimate biomass concentration of activated sludge as a function of time and ozone dose rate; in contrast, at the doses applied, chlorine did not reduce the concentration of activated sludge biomass. In activated sludge, adequate conditions for both oxidants were identified under which the respiratory activity of filamentous micro-organisms could be considerably inhibited, causing the lowest possible impact on whole floc metabolic activity. An initial chlorine dose of 7.9 mgCl2·gVSS-1 for a contact time of 5 min (initial pulse= 6.0 mgCl2·l-1), and a total ozone dose of 66.0 mgO3·gVSS-1 (ozone dose rate of 3.3 mgO3·gVSS-1·min-1 for a contact time of 20 min) were the most suitable conditions to control filamentous bulking.Centro de Investigación y Desarrollo en Criotecnología de Alimentos2006info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf585-595http://sedici.unlp.edu.ar/handle/10915/128235enginfo:eu-repo/semantics/altIdentifier/issn/0378-4738info:eu-repo/semantics/altIdentifier/doi/10.4314/wsa.v32i4.5283info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:31:02Zoai:sedici.unlp.edu.ar:10915/128235Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:31:02.978SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
title Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
spellingShingle Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
Caravelli, Alejandro Horacio
Química
Filamentous bulking
Chlorine
Ozone
INT-dehydrogenase activity
Respirometry
Image analysis
Late count
title_short Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
title_full Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
title_fullStr Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
title_full_unstemmed Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
title_sort Effectiveness of chlorination and ozonation methods on pure cultures of floc-forming micro-organisms and activated sludge: a comparative study
dc.creator.none.fl_str_mv Caravelli, Alejandro Horacio
Giannuzzi, Leda
Zaritzky, Noemí Elisabet
author Caravelli, Alejandro Horacio
author_facet Caravelli, Alejandro Horacio
Giannuzzi, Leda
Zaritzky, Noemí Elisabet
author_role author
author2 Giannuzzi, Leda
Zaritzky, Noemí Elisabet
author2_role author
author
dc.subject.none.fl_str_mv Química
Filamentous bulking
Chlorine
Ozone
INT-dehydrogenase activity
Respirometry
Image analysis
Late count
topic Química
Filamentous bulking
Chlorine
Ozone
INT-dehydrogenase activity
Respirometry
Image analysis
Late count
dc.description.none.fl_txt_mv Chlorination is a very useful control method of filamentous bulking in activated sludge systems; however, it favours formation; of undesirable compounds such as trihalomethanes. Other oxidants, such as ozone, could be used for bulking control. In view of the fact that chlorine and ozone are both non-selective chemical agents affecting filamentous and floc-forming micro-organisms, the determination of optimum dosage conditions becomes essential to minimise the impact produced on the activated sludge process. In this work, the effects of chlorine and ozone on the biomass concentration of activated sludge and on different parameters that characterise the microbial metabolic activity were compared. The following techniques were applied: Respirometry (oxygen uptake rate); and INT-dehydrogenase activity test carried out both by spectrophotometry (DHAa) and image analysis (DHAi). The respirometric technique and the DHAa test quantified oxidants action on the total respiratory activity of flocs; the image DHAi test was applied to evaluate the specific action of the oxidants on filamentous micro-organisms. Additionally, plate count technique, respirometry and DHAa test were correlated using chlorine and ozone experiments on pure cultures of a floc-forming micro-organism (Acinetobacter anitratus) to compare the effect of the oxidising; agents on the metabolic activity and the viability of the micro-organisms. Ozone was found to have more intense antimicrobial action. In activated sludge, ozone reduced total biomass concentration by oxidising various components and causing cell lysis. An equation was proposed to estimate biomass concentration of activated sludge as a function of time and ozone dose rate; in contrast, at the doses applied, chlorine did not reduce the concentration of activated sludge biomass. In activated sludge, adequate conditions for both oxidants were identified under which the respiratory activity of filamentous micro-organisms could be considerably inhibited, causing the lowest possible impact on whole floc metabolic activity. An initial chlorine dose of 7.9 mgCl2·gVSS-1 for a contact time of 5 min (initial pulse= 6.0 mgCl2·l-1), and a total ozone dose of 66.0 mgO3·gVSS-1 (ozone dose rate of 3.3 mgO3·gVSS-1·min-1 for a contact time of 20 min) were the most suitable conditions to control filamentous bulking.
Centro de Investigación y Desarrollo en Criotecnología de Alimentos
description Chlorination is a very useful control method of filamentous bulking in activated sludge systems; however, it favours formation; of undesirable compounds such as trihalomethanes. Other oxidants, such as ozone, could be used for bulking control. In view of the fact that chlorine and ozone are both non-selective chemical agents affecting filamentous and floc-forming micro-organisms, the determination of optimum dosage conditions becomes essential to minimise the impact produced on the activated sludge process. In this work, the effects of chlorine and ozone on the biomass concentration of activated sludge and on different parameters that characterise the microbial metabolic activity were compared. The following techniques were applied: Respirometry (oxygen uptake rate); and INT-dehydrogenase activity test carried out both by spectrophotometry (DHAa) and image analysis (DHAi). The respirometric technique and the DHAa test quantified oxidants action on the total respiratory activity of flocs; the image DHAi test was applied to evaluate the specific action of the oxidants on filamentous micro-organisms. Additionally, plate count technique, respirometry and DHAa test were correlated using chlorine and ozone experiments on pure cultures of a floc-forming micro-organism (Acinetobacter anitratus) to compare the effect of the oxidising; agents on the metabolic activity and the viability of the micro-organisms. Ozone was found to have more intense antimicrobial action. In activated sludge, ozone reduced total biomass concentration by oxidising various components and causing cell lysis. An equation was proposed to estimate biomass concentration of activated sludge as a function of time and ozone dose rate; in contrast, at the doses applied, chlorine did not reduce the concentration of activated sludge biomass. In activated sludge, adequate conditions for both oxidants were identified under which the respiratory activity of filamentous micro-organisms could be considerably inhibited, causing the lowest possible impact on whole floc metabolic activity. An initial chlorine dose of 7.9 mgCl2·gVSS-1 for a contact time of 5 min (initial pulse= 6.0 mgCl2·l-1), and a total ozone dose of 66.0 mgO3·gVSS-1 (ozone dose rate of 3.3 mgO3·gVSS-1·min-1 for a contact time of 20 min) were the most suitable conditions to control filamentous bulking.
publishDate 2006
dc.date.none.fl_str_mv 2006
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info:eu-repo/semantics/publishedVersion
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dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/128235
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language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0378-4738
info:eu-repo/semantics/altIdentifier/doi/10.4314/wsa.v32i4.5283
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
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