Laboratory study of ballasted flocculation

Desjardins, Christian; Koudjonou, Boniface; Desjardins, Raymond L.

doi:10.1016/s0043-1354(01)00256-1

Cited by 94 publications

(47 citation statements)

References 6 publications

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“…Elle permet ainsi d'accélérer le processus de clarification sans augmenter la demande en coagulant. Ce constat se rapproche de celui avancé par DESJARDINS et al (2002) qui montre l'importance de l'utilisation d'un microsable pour faire augmenter la densité du floc et accroître sa vitesse de sédimentation. Il est à noter que la présence de la bentonite influence non seulement les paramètres hydrodynamiques et cinétiques du système, mais aussi la structuration des agrégats.…”

Section: Effet De La Bentonite Sur L'agrégationunclassified

Traitement combiné d’un effluent textile contenant des colorants réactifs par coagulation-floculation et électroflottation

Bouyakoub

Kacha

Ouhib

et al. 2010

rseau

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Les effluents textiles contenant des colorants réactifs sont souvent très complexes et nécessitent des traitements intensifs. De nos jours, la combinaison de deux ou plusieurs techniques opératoires, en se servant des progrès scientifiques permettant une bonne commande du procédé, est devenue une alternative intéressante. Par ailleurs, les argiles et les minéraux argileux, du fait d’avoir des propriétés leur permettant d’être à la fois adsorbants et adjuvants de floculation, attirent un intérêt particulier des chercheurs dans le domaine du traitement des effluents industriels. Dans cette étude, un effluent textile qui représente les eaux résiduaires de l’unité de teinture du coton Denitex, Tlemcen en Algérie, a été traité par un procédé combiné. Le traitement comporte deux étapes : la première est une coagulation-floculation (CF) à l’aide des sels d’aluminium pré-neutralisés jusqu’à un rapport OH/Al égal à 2,25, donnant naissance au polycation de structure AlO4Al12(OH)24(H2O)12, appelé aussi Al13, en association avec une bentonite algérienne (B). Dans la deuxième étape, qui succède à la première, l’électroflottation (EF) a été utilisée pour exploiter son rôle de séparation solide-liquide, et aussi pour améliorer l’efficacité du traitement. Dans les deux techniques utilisées : (CF) et (EF), les conditions opératoires, telles que le pH, la concentration des réactifs, le temps de contact, d’une part, et aussi la densité du courant électrique et la consommation d’énergie, d’autre part, ont été déterminées. Les résultats obtenus indiquent que l’effluent traité par cette méthode ne contient pratiquement plus de couleur ni de DCO : 99,71 % et 99,07 % d’élimination sont obtenus, respectivement.Textile effluents containing reactive dyes are often very complex and require intensive treatments. Nowadays, the combination of two or more techniques has become an interesting alternative, because of scientific progress allowing for a good control of the processes. Clays and clay minerals, because of their properties enabling them to be simultaneous adsorbents and flocculation additives, are of particular interest to researchers in industrial wastewater treatment. In this study, a textile effluent that represents the wastewater of a cotton dyeing plant (Denitex, Tlemcen, Algeria) was treated by a combined process. The treatment was divided into two stages: the first was a coagulation-flocculation (CF) stage using pre-neutralized aluminium salts, called Al13 polycations (AlO4Al12(OH)24(H2O)12), as a coagulant associated with an Algerian bentonite (B); in the second stage, an electroflotation technique (EF) was used. The EF technique was not only used as a solid-liquid separation operation, but also in the improvement of the effectiveness of the treatment. For the CF and EF treatments of wastewater, the effects of pH, reagent concentrations, contact times as well as electric current and energy consumption were investigated. The effluent treated by this combined method contained essentially no colour or COD: 99.7% and 99.1% eliminat...

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Section: Effet De La Bentonite Sur L'agrégationunclassified

Traitement combiné d’un effluent textile contenant des colorants réactifs par coagulation-floculation et électroflottation

Bouyakoub

Kacha

Ouhib

et al. 2010

rseau

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show abstract

“…There is a general understanding of the role of magnetic seeding, micro-sand, diatomite, and recycled DWTS in enhancing coagulation. Magnetic seeding and micro-sand assisted flocculation are now widely accepted technical alternatives to strengthen separation during the treatment of drinking water, reclaimed water, or landscape water [3][4][5][6][7][8]. However, the application of recycled DWTS from drinking water treatment is restricted due to potential negative effects of complex components within the recycled DWTS.…”

Section: Introductionmentioning

confidence: 99%

The removal characteristics of natural organic matter in the recycling of drinking water treatment sludge: Role of solubilized organics

Zhou

Yang

et al. 2016

Ultrasonics Sonochemistry

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To clarify the role of solubilized organics derived from drinking water treatment sludge (DWTS) in the elimination of natural organic matter (NOM) in the DWTS recycling process, a probe sonoreactor at a frequency of 25 kHz was used to solubilize the organics at varied specific energies. The coagulation behavior related to NOM removal in recycling the sonicated DWTS with and without solubilized organics was evaluated, and the effect on organic fractionations in coagulated water was determined. The study results could provide useful implications in designing DWTS recycling processes that avoid the enrichment of organic matter. Our results indicate that DWTS was disrupted through a low release of soluble chemical oxygen demand (SCOD) and proteins, which could deteriorate the coagulated water quality under the specific energy of 37.87-1212.1 kW h/kg TS. The optimal coagulation behavior for NOM removal was achieved by recycling the sonicated DWTS without solubilized organics at 151.5 kW h/kg TS specific energy. Recycling the sonicated DWTS could increase the enrichment potential of weakly hydrophobic acid, hydrophilic matter, and <3 kDa fractions; the enrichment risks could be reduced by discharging the solubilized organics. Fluorescent characteristic analysis indicated that when recycling the sonicated DWTS without solubilized organics, the removal of humic-like substances was limited, whereas removal of protein-like substances was enhanced, lowering the enrichment potential of protein-like substances.

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“…The process is based on the use of Al(III) or Fe(III) salts alone or in combination with polymers as flocculants. Many factors can affect the coagulation-flocculation efficiency, such as the type and dosage of the coagulant/flocculant, [13] pH, [14,15] mixing, [16] temperature and retention time. [17] The optimization of these factors may significantly increase the process efficiency.…”

Section: Introductionmentioning

confidence: 99%

Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process

Cheibub

Campos

Fonseca

2014

Journal of Environmental Science and Health, Part A

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This work investigated the effectiveness of a physicochemical and oxidative process for the removal of chemical oxygen demand (COD) from stabilized landfill leachates. The application of these technologies for landfill leachate treatment greatly depends on the optimal operating conditions for a specific leachate. Coagulation-flocculation followed by H2O2, Fenton and photo-Fenton processes was evaluated. Advanced oxidation processes were evaluated in the raw leachate and the leachate pretreated by coagulation-flocculation. Via the coagulation process, at 30 sec and a stirring speed of 150 rpm followed by flocculation and settling steps, 53% COD was removed at an optimal dose of 1400 mg L(-1) and pH 4.0. Moreover, from the POA evaluated, the Fenton process was determined to be the most effective process for removing COD from the leachate pretreated by coagulation-flocculation, reaching 83.3% COD removal with 1330 mg L(-1) of H2O2 and 266 mg L(-1) of Fe(2+). The photo-Fenton process applied directly to the raw effluent was effective for the removal of COD; a 75% reduction in COD was observed in tests using 2720 mg L(-1) of H2O2 and 544 mg L(-1) of Fe(2+). Due to the variability in the composition of the Gramacho landfill leachate, the combination of coagulation-flocculation and the Fenton process is an effective technology for reducing the COD in samples of this leachate.

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Laboratory study of ballasted flocculation

Cited by 94 publications

References 6 publications

Traitement combiné d’un effluent textile contenant des colorants réactifs par coagulation-floculation et électroflottation

Traitement combiné d’un effluent textile contenant des colorants réactifs par coagulation-floculation et électroflottation

The removal characteristics of natural organic matter in the recycling of drinking water treatment sludge: Role of solubilized organics

Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process

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