A study on the removal of organic substances from low-turbidity and low-alkalinity water with metal-polysilicate coagulants

Cheng, Wen Po; Hwa, Fung; Li, Chun Chang; Yu, Ruey-Fang

doi:10.1016/j.colsurfa.2007.06.060

Cited by 102 publications

(41 citation statements)

References 22 publications

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“…The results showed that the turbidity of the raw water in Yangtze River was about 40 NTU, which was considered as low to medium turbidity, and the value is a bit lower than the previous results reported from other research groups [15,16]. It is considered to be diffi cult to treat the raw water with low turbidity using the traditional coagulation-fl occulation process, as the concentration of particles in the water is too low to cause effective particle collision and aggregation [17,18]. The DOC, UV254, and specifi c ultraviolet absorbance (SUVA) values were 1.53 mg l −1 , 4.06 m −l , and 2.65 l (mg m) −1 , respectively, indicating that the water has a low potential to form the disinfection by products [19].…”

Section: Water Characteristics Of the Wtpcontrasting

confidence: 46%

Turbidity removal improvement for Yangtze River raw water

Lei

Lou

Song³

et al. 2012

Desalination and Water Treatment

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A B S T R AC TCoagulation-fl occulation followed by sedimentation and fi ltration is the most commonly used water treatment process, in which turbidity or particle removal is strongly dependent on proper coagulant dosage, fl occulation mixing time, mixing intensity (Gt), and effective size (ES) of fi lter media. Jar tests and fi ltration column tests were preformed in this study to evaluate the turbidity removal of the Yangtze River raw water that has medium turbidity and low dissolved organic matters. The new internal standard of 1 NTU for settled water and 0.2 NTU for outlet water were targeted. Operational conditions of primary fl occulation (coagulant amount, mixing time and Gt), secondary fl occulation, and fi lter media ES, were tested. Results showed that under the same amount of coagulant, longer fl occulation time and higher Gt with tapered mixing can enhance the turbidity removal. The optimal dosage and Gt were estimated as 12 mg l −1 PACL and 29,000, respectively. Secondary fl occulation further reduced the turbidity of settled water by 80%, suggesting that the smaller particles retained in the primary settled water was focculable. Compared to using 0.95 mm ES, using 0.65 mm ES as fi lter media obtained higher turbidity removal and can lower the residual turbidity to 0.15 NTU.

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Section: Water Characteristics Of the Wtpcontrasting

confidence: 46%

Turbidity removal improvement for Yangtze River raw water

Lei

Lou

Song³

et al. 2012

Desalination and Water Treatment

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“…3b, c). The mechanisms to explain the coagulation of particle and DOM include charge neutralization, precipitation, bridge-aggregation, adsorption, and sweep-flocculation (Cheng et al 2008). When diatomite is added prior to PAC, diatomite can be embedded in the flocs, improve the structure of flocs, increase the floc density, and improve sedimentation performance (Wu et al 2011).…”

Section: Resultsmentioning

confidence: 99%

Enhanced coagulation for improving coagulation performance and reducing residual aluminum combining polyaluminum chloride with diatomite

2015

Environ Sci Pollut Res

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The feasibility of using enhanced coagulation, which combined polyaluminum chloride (PAC) with diatomite for improving coagulation performance and reducing the residual aluminum (Al), was discussed. The effects of PAC and diatomite dosage on the coagulation performance and residual Al were mainly investigated. Results demonstrated that the removal efficiencies of turbidity, dissolved organic carbon (DOC), and UV254 were significantly improved by the enhanced coagulation, compared with PAC coagulation alone. Meaningfully, the five forms of residual Al (total Al (TAl), total dissolved Al (TDAl), dissolved organic Al (DOAl), dissolved monomeric Al (DMAl), and dissolved organic monomeric Al (DOMAl)) all had different degrees of reduction in the presence of diatomite and achieved the lowest concentrations (0.185, 0.06, 0.053, 0.014, and 0 mg L(-1), respectively) at a PAC dose of 15 mg L(-1) and diatomite dose of 40 mg L(-1). In addition, when PAC was used as coagulant, the majority of residual Al existed in dissolved form (about 31.14-70.16%), and the content of DOMAl was small in the DMAl.

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“…Based on previous studies [32,33], different mechanisms or their combination may be dominant under different conditions. For Al 2 (SO 4 ) 3 , the influence of the pH on coagulation mechanisms was correlated with the coagulant hydrolysed species [11].…”

Section: Effects Of Ph On Dissolved Residual Al Concentrationmentioning

confidence: 99%

Influence of coagulation mechanisms on the residual aluminum – The roles of coagulant species and MW of organic matter

Jiao

et al. 2015

Journal of Hazardous Materials

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A study on the removal of organic substances from low-turbidity and low-alkalinity water with metal-polysilicate coagulants

Cited by 102 publications

References 22 publications

Turbidity removal improvement for Yangtze River raw water

Turbidity removal improvement for Yangtze River raw water

Enhanced coagulation for improving coagulation performance and reducing residual aluminum combining polyaluminum chloride with diatomite

Influence of coagulation mechanisms on the residual aluminum – The roles of coagulant species and MW of organic matter

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