Temperature Effects on the Use of Metal‐Ion Coagulants for Water Treatment

Morris, Juli K.; Knocke, William R.

doi:10.1002/j.1551-8833.1984.tb05302.x

Cited by 68 publications

(56 citation statements)

References 3 publications

(2 reference statements)

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“…The floc size was small when it was observed with the naked eye at 5 o C, and the formation of floc was difficult to identify during the process of slow agitation. This was consistent with the report of Morris and Knocke [1984] that showed a decrease in the turbidity removal and smaller flocs under low temperature with alum as a coagulant. It was observed that ferric chloride was less sensitive in the changes in temperature than was PAC.…”

Section: Effect Of Ph and Temperature On Removal Of Doc And Turbiditysupporting

confidence: 94%

“…Morris and Knocke reported that ferric chloride was less influenced at a low temperature compared with alum, and they suggest the combination of alum and ferric chloride as a potential method [14]. However, Johnson and Amirtharajah reported the coagulation performance was not evidently enhanced by the combination of alum and ferric chloride [27].…”

Section: Introductionmentioning

confidence: 95%

“…The efficiency of coagulation is influenced by certain factors, such as pH, temperature, alkalinity, coagulant type, and mixing intensity [12][13][14][15][16][17]. Many researchers have recommended a pH adjustment method to enhance the coagulation efficiency [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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Improvement in the coagulation performance by combining Al and Fe coagulants in water purification

Lee¹,

Lee

Nam

2008

Korean J. Chem. Eng.

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This study evaluated the beneficial effects on the coagulation process of combining coagulants with Fe and Al in the removal of turbidity and DOC (dissolved organic carbon), and proposed conditions for proper operation of a coagulation process. In addition, the floc characteristics and sludge dewater ability were evaluated. Blended coagulants were more effective than single coagulants at lower concentrations in water purification. The optimal blended ratio for the removal of DOC was 1.45 mM as Al/mM as Fe. Also, blended coagulants were less affected than single coagulants by pH, temperature, and rapid mixing intensity. Based on the results of the change in the apparent molecular weight distribution (AMWD) of DOC in raw and treated water by coagulation, low molecular weight organic matters were removed by 40.7% for the blended coagulant (1.45 mM as Al/mM as Fe). Blended coagulants formed larger flocs than single coagulants did. At pH 6.0, floc strength and sludge dewaterablity were both improved.

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Section: Effect Of Ph and Temperature On Removal Of Doc And Turbiditysupporting

confidence: 94%

Section: Introductionmentioning

confidence: 95%

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Improvement in the coagulation performance by combining Al and Fe coagulants in water purification

Lee¹,

Lee

Nam

2008

Korean J. Chem. Eng.

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“…The optimum pH varies inversely with temperature. Morris and Knocke (1984) reported that with either alum coagulation or ferric chloride coagulation, the floes at 1 °C are generally smaller than those formed at 20°C (Figure 6-3 (a) and (b)). They also found that low temperature has a significant effect on turbidity removal for both coagulants, as shown in Figure 6-3 (c) and (d), although the effect was not as severe for ferric chloride as for aluminum sulfate.…”

Section: Coagulation and Flocculationmentioning

confidence: 92%

Water Treatment

Smith¹,

Stanley²

1996

Cold Regions Utilities Monograph

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“…Pour MOHTADI et RAO (1973) et KOWAL et MACKIEWICZ (1975, cette dégradation est due au pH optimum de coagulation qui croît lorsque la température s'abaisse, DOLEJS (1983,1984), dans deux études consécutives sur des eaux chargées en matières humiques, montre lui, qu'une agitation plus intense après l'injection du coagulant peut, à faible température, améliorer le rendement d'élimination des colloïdes et que selon l'alcalinité du milieu l'effet de la température peut varier. L'action limitante de la température peut également être atténuée, comme le précisent MORRIS et KNOCKE (1984), en augmentant la concentration des matières en suspension. En 1986, BAZER-BACHI confirme le déplacement du pH optimum de coagulation avec la température sur des eaux qui ont des caractéristiques physico-chimiques proches de celles de la Garonne.…”

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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Temperature Effects on the Use of Metal‐Ion Coagulants for Water Treatment

Cited by 68 publications

References 3 publications

Improvement in the coagulation performance by combining Al and Fe coagulants in water purification

Improvement in the coagulation performance by combining Al and Fe coagulants in water purification

Water Treatment

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

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