The hydrophilic/hydrophobic ratio vs. dissolved organics removal by coagulation – A review

To improve the organics removal efficiency of surface water treatment technologies, powdered activated carbon (PAC) has often been added. Some of the PAC particles with the dissolved organics already adsorbed are present in the form of a colloidal quasi-colloidal dispersion and can be removed most efficiently by coagulating and flocculating them together with the natural suspended solids. This, however, cannot be accomplished unless the PAC is added 3-5 minutes ahead under violent stirring of the water to be treated. Laboratory data demonstrated that the PAC and the Al-hydroxides formed of the coagulant (Al-salt) added remove different types of organics from the water and consequently do not compete with each other.

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Removal of Organic Matter by Physico-Chemical Mechanisms in Wastewater Treatment Plants

Water Science & Technology ◽

10.2166/wst.1993.0275 ◽

1993 ◽

Vol 27 (11) ◽

pp. 167-183 ◽

Cited By ~ 11

Author(s):

M. Boller

Keyword(s):

Organic Matter ◽

Wastewater Treatment ◽

Wastewater Treatment Plants ◽

Separation Performance ◽

Chemical Mechanisms ◽

Organics Removal ◽

Trace Organics ◽

Dissolved Organics ◽

Physico Chemical ◽

Solids Separation

Solids separation, adsorption onto participates and volatilization are the main physico-chemical mechanisms responsible for the removal of organic matter in wastewater treatment plants. In addition, solids separation as well as adsorption performance may be enhanced by chemical flocculation/precipitation with hydrolyzing metal salts. With the help of particle size distributions and other characteristics of the particulates at different treatment stages, more insight can be gained into the interactions between paniculate properties and solids separation performance. Significant removal of trace organics is achieved by adsorption onto paniculate surfaces and stripping in aeration tanks. Examples illustrate the adsorption of the relatively large quantities of substances contained in detergents and reveal the effect on water and sludge quality. Octanol/water partition coefficients of trace organics may be used together with oxygen transfer characteristics to determine the potential of volatilization into the air. The effect of flocculants on paniculate and dissolved organics removal in wastewater treatment is illustrated when Fe-salts are dosed to raw sewage, to the biological stage or to tertiary filters.

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The Fate of Dissolved Organics in Water Purification Processes Treating Polluted Raw Water

Water Science & Technology ◽

10.2166/wst.1993.0266 ◽

1993 ◽

Vol 27 (11) ◽

pp. 71-80 ◽

Cited By ~ 8

Author(s):

Hsuan-Hsien Yeh ◽

Winn-Jung Huang

Keyword(s):

Adverse Effect ◽

Humic Acid ◽

Water Treatment ◽

Fulvic Acid ◽

Water Purification ◽

Raw Water ◽

Treatment Processes ◽

Organics Removal ◽

Dissolved Organics ◽

Hydrophilic Fraction

The main purpose of this study is to look into the fate of dissolved organics through conventional water treatment processes preceded by prechlorination with high dosage to treat polluted raw water. In addition to organic surrogate parameters analyses, organics were fractionated into humic acid, fulvic acid, hydrophilic-acid and -neutral-four fractions. The results showed that the removal of hydrophilic fraction organics were limited, and prechlorination probably transformed some organics from other fractions into hydrophilic-neutral fractions. Therefore although prechlorination with high dosage could facilitate the plant operation when treating polluted raw water, it probably had some adverse effect on dissolved organics removal.

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Determination of the Size Distribution of Dissolved Organics in Effluents

Water Quality Research Journal ◽

10.2166/wqrj.1973.003 ◽

1973 ◽

Vol 8 (1) ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

L.A. Addie ◽

K.L. Murphy ◽

J.L. Robertson

Keyword(s):

Size Distribution ◽

Biological Treatment ◽

Oxygen Demand ◽

Molecular Size ◽

Monitoring Systems ◽

Clean Surface ◽

Sephadex Column ◽

Dissolved Organics ◽

Molecular Size Distribution

Abstract The importance of removing the small amounts of residual organics is increasing as the sources of clean surface water decrease. Knowledge of the nature of these soluble residual organics will be needed in order to assess the type of treatment required for their removal. Residual organics in three different biological treatment plants were analyzed and compared. An attempt was made to characterize these organics by a molecular size distribution on a Sephadex column monitored by differential ultraviolet and refractive index detectors. The organic carbon and chemical oxygen demand of the fractions collected from the column was also determined. An investigation of some of the problems inherent in the monitoring systems was conducted.

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