Chemical Aspects of Coagulation

Stumm, Werner; Morgan, James J.

doi:10.1002/j.1551-8833.1962.tb00922.x

Cited by 208 publications

(99 citation statements)

References 35 publications

(1 reference statement)

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“…These hydroxides are hydrophobic, causing them to adsorb onto the organic anionic particle surface and become insoluble [16,17].Copper and aluminium cations tend to associate and complex with a number of functional groups and ligands, especially with polar molecules and with oxygen containing functional groups like hydroxyl, phenolic and carboxylic groups [19][20][21]. The local negative charge of these groups is neutralised by the Al and Cu cations, resulting in colloid destabilization and precipitation of the metal (cations) -organics (anions) complexes.…”

Section: Danalytical Methodsmentioning

confidence: 99%

Treatment of paper and pulp mill effluent by coagulation

Chaudhari

Majumdar

Choudhary

et al. 2010

Environmental Technology

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Abstract-The pulp and paper mill effluent is one of the high polluting effluent amongst the effluents obtained from polluting industries. All the available methods for treatment of pulp and paper mill effluent have certain drawbacks. The coagulation is one of the cheapest process for treatment of various organic effluents. Thus, the removal of chemical oxygen demand (COD) and colour of paper mill effluent is studied using coagulation process. The batch coagulation process was performed using various coagulants like: aluminium chloride, poly aluminium chloride and copper sulphate. The initial pH of the effluent (Coagulation pH) has tremendous effect on COD and colour removal. Poly aluminium chloride (PAC) as coagulant reduced COD to 84 % and 92 % of colour was removed at an optimum pH 5 and coagulant dose of 8 ml l -1 . With aluminium chloride at an optimum pH = 4 and coagulant dose of 5 g l -1 , 74 % COD and 86 % colour removal were observed. The results using copper sulphate as coagulant (a less commercial coagulant) were encouraging. At an optimum pH 6 and mass loading of 5 g l -1, 76 % COD reduction and 78 % colour reduction were obtained. It was also observed that after addition of coagulant, the pH of the effluent decreases. The decrease in pH was highest for AlCl 3, which was followed by PAC and CuSO 4 . Significant amount of COD reductions was obtained by coagulation process. Since the coagulation process is the first stage for treatment of effluent and some of the coagulant cations usually remain in the treated effluents. Thus, cation like copper may be one of the good catalyst for second stage of treatment process like wet oxidation. The copper has been found to be good oxidation catalyst then iron and aluminum.

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Section: Danalytical Methodsmentioning

confidence: 99%

Treatment of paper and pulp mill effluent by coagulation

Chaudhari

Majumdar

Choudhary

et al. 2010

Environmental Technology

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“…Their hydroxyl-aluminum polymers were recognized as the most effective components in Al coagulants [1][2][3]. A thorough understanding of the nature and properties of the hydrolyzed-Al species in partially neutralized solutions should be of great help in the understanding of coagulation mechanisms and the improvement of inorganic polymer flocculants.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of hydroxyl-aluminum species at lower OH/Al ratios by combination of 27Al NMR and Ferron assay improved with kinetic resolution

Feng

Tang

Wang

2007

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Depuis MARION et THOMAS (1946), STUMM et MORGAN (1962, PACKHAM (1965), HANNA et RUBIN (1970), de HEK et al (1978, LETTERMAN étal. (1977LETTERMAN étal.…”

Section: Pour Pallier Ces Inconvénients Le Service Des Eaux De La VIunclassified

Modélisation mathématique du taux de coagulant dans une station de traitement d'eau

Bazer-Bachi¹,

Puech-Coste²,

Aim³

et al. 2005

rseau

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Les auteurs, après une synthèse bibliographique sur la coagulation, présentent deux modèles mathématiques reliant la dose optimale d'un coagulant, le sulfate d'aluminium, à la qualité de l'eau brute.Un premier modèle applicable aux eaux dont la turbidité est inférieure à 20 NTU tient compte de quatre variables caractéristiques de l'eau brute qui sont : la turbidité, la résistivité, la température, la teneur en matières organiques.Le second modèle, utilisable pendant les périodes de crue, intègre un cinquième descripteur : la nature de la suspension minérale.Des essais effectués sur l'usine de Clairfont, qui alimente la rive gauche de Toulouse, montrent que ces modèles sont parfaitement adaptés pour automatiser l'injection du coagulant.When the source of supply of a water treatment plant has a streaming behaviour, it is sometimes difficult to adjust correctly the coagulant dose by jar-testing alone.Following this remark, the municipal water utilities of Toulouse city (France) has decided to conduct a study on the modelisation of coagulant dose as a function of the quality of raw water.This study started first by a bibliographic survey to find the main parameters which affect the flocculation mechanisms, followed by a hydrologic study of the upper Garonne river to characterize as well as possible its behavior.This was following by a study of the influence of certain parameters on the efficiency of coagulation by aluminium sulfate on synthetic waters having characteristics close to those of the Garonne river (BAZER-BACHI, 1986). This work showed the rote of the turbidity, of the resistivity, of the temperature and of the nature of mineral suspension. It also indicated the non-linearity between the optimum coagulant dose and these parameters as well as the interactions between them.These conclusions led us to use a second degree polynomial model, as : k k kY = bo + ∑ bi Xi + ∑ bii X2i + ∑ bij Xi Xj i = 1, j = 2, i ≠ jData were collected from modified jar-test on water from the Garonne River, characterized by physico-chemical (turbidity, temperature, pH, resistivity, CEC, MES, colloid titralion, organic matters) and chemical analyses (mineralisation). As the hydrological study showed that the nature of colloid suspension changed only during storm events, the modelisation was divided in two sub-groups :- a « CALME » model, comprising four variables (turbidity, resistivity, temperature, organic matters), for low turbidity waters (below 20 NTU),- a « CRUES » a model, using a fifth parameter representative of the nature of suspension (the ratio between colloid titration and turbidity).The « CALME » model, which fitted very well, showed the primordial influence of the temperature and organic matters, and then of the turbidity. Removal of resistivity was not advisable, as this parameter showed strong interactions with turbidity and organic matters (fig. 3, 4).The « CRUES » model showed the primordial role of the turbidity followed by the temperature and then by organic matters. The tw...

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Chemical Aspects of Coagulation

Cited by 208 publications

References 35 publications

Treatment of paper and pulp mill effluent by coagulation

Treatment of paper and pulp mill effluent by coagulation

Differentiation of hydroxyl-aluminum species at lower OH/Al ratios by combination of 27Al NMR and Ferron assay improved with kinetic resolution

Modélisation mathématique du taux de coagulant dans une station de traitement d'eau

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