Water treatment coagulation

J. Gregory and V. Dupont, Properties of floes produced by water treatment coagulants, Water Sci. Technol. 44, 231-243 (2001). 

Uses Emulsifier, dispersant, emollient, surfactant, softener, conditioner, bactericide, fungicide, odor inhibitor in personal care prods., pharmaceuticals preservative In cosmetics antistat for hair, fibers, plastics antistat, softener for textile finishes gel sensitizer In latex foam prod. emulsion polymerization germicide (duckweed killer), dispersant, coagulant for water treatment coagulant in antibiotic prod. germicide in foods, fermentation Regulatory FDA approved for topicals Manuf./Distrib. Accord Aldrich Fluka Trade Names Containing SEM 601... 

The following steps are involved in the water treatment. Coagulation and filtration of suspended materials are the oldest techniques employed for water treatment. 

H. M. Kwaambwa and R. Maikokera, Infrared and circular dichroism spectroscopic characterisation of secondary structure components of a water treatment coagulant protein extracted from Moringa oleifera seeds, Colloids and Surfaces B, vol. 64, no. 1, pp. 118—125, 2008. 

Water Treatment Industrial CleaningPipplications. Boiler and cooling tower waters are treated with lignosulfonates to prevent scale deposition (78). In such systems, lignosulfonates sequester hard water salts and thus prevent their deposition on metal surfaces. They can also prevent the precipitation of certain iasoluble heat-coagulable particles (79). Typical use levels for such appHcatioas range from 1—1000 ppm. 

Disposal of the solutions of aluminum salts generated in the Eriedel-Crafts process presents an environmental problem unless use can be found for them as coagulants in a water treatment plant. 

Makeup. Makeup treatment depends extensively on the source water. Some steam systems use municipal water as a source. These systems may require dechlorination followed by reverse osmosis (qv) and ion exchange. Other systems use weUwater. In hard water areas, these systems include softening before further purification. Surface waters may require removal of suspended soHds by sedimentation (qv), coagulation, flocculation, and filtration. Calcium may be reduced by precipitation softening or lime softening. Organic contaminants can be removed by absorption on activated carbon. Details of makeup water treatment may be found in many handbooks (22—24) as well as in technical Hterature from water treatment chemical suppHers. 

Both iron and aluminum are particulady troublesome because of their abiUty to act as coagulants. Also, their soluble and insoluble hydroxide forms can each cause precipitation of some water treatment chemicals, such as orthophosphate. Airborne contaminants usually consist of clay and dirt particles but can include gases such as hydrogen sulfide, which forms insoluble precipitates with many metal ions. Process leaks introduce a variety of contaminants that accelerate deposition and corrosion. 

Parking areas Primary water treatment—filtration, coagulation, aeration... 

Another use for sulfuric acid is in water treatment. Aluminum sulfate, which is produced by treating sulfuric acid with aluminum oxide, is a top-50 industrial chemical because of its widespread use as a coagulant. Addition of AI2 (804)3 Ca(OH)2 generates a gelatinous precipitate of aluminum hydroxide mixed with calcium sulfate AI2 (804)3 ) (OH)2 (tJ ( ) A Al (OH)3 (. ) + CaS04(.S ) The gel traps finely suspended... 

This plant produces 130 m2/h of enameled steel and operates 3500 h/yr. It uses 0.0036 m3 water/m2 of product to coat the steel. Average process water flow is 0.144 m3/h for coating operations and 0.734 m3/h for metal preparation. The primary treatment in-place for process wastewater is clarification and settling. Other water treatment practices employed are pH adjustment with lime or acid, sludge applied to landfill, polyelectrolyte coagulation, and inorganic coagulation. 

Fitzgerald, C.L., Clemens, M.M., Reilly, P.B., Jr. Coagulants for Waste Water Treatment, Chemical Engineering Progress, Jan. 1970p. 36. 

Brillas E, Casado J (2002) Aniline degradation by electro-Fenton and peroxi-coagulation processes using a flow reactor for waste water treatment. Chemosphere 47(3) 241-248... 

Water treatment, 26 102-152. See also Aeration water treatment, Industrial water treatment ABS manufacture, 7 421-422 activated carbon application, 4 752 aerators, 26 158-170 alkanolamines from nitro alcohols, 2 120 coagulation and flocculation in,... 

Laboratory-scale test procedures consisting of jar test studies have been used for years, and the test methodology developed is such that full-scale designs can be developed from these studies with a high degree of confidence. A jar test is a series of bench-scale laboratory procedures made on 1- or 2-1 water samples to determine the most effective water treatment method. Tests are performed to identify the most effective coagulants, optimum dosage, optimum pH, and most effective order in which to add various chemicals. 

Equilibrium composition of solutions in contact with freshly precipitated, Al(OH)3 and Fe(OH)3, calculated, using representative values for the equilibrium constants for solubility and hydrolysis equilibria. Shaded areas are approximate operating regions in water treatment practice coagulation in these systems occurs under conditions of oversaturation with respect to the metal hydroxide. 

Vieno N, Tuhkanen T, Kronberg L (2006) Removal of pharmaceuticals in drinking water treatment effect of chemical coagulation. Environ Technol 27 183-192... 

Studies on conventional drinking-water treatment processes, such as filtration, coagulation and sedimentation, have shown that coagulation is largely ineffective in removing pharmaceuticals. Free chlorine is able to remove up to approximately 50% of the pharmaceuticals investigated, whereas chloramines have lower removal... 

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