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Primary treatment
Published in Rumana Riffat, Taqsim Husnain, Fundamentals of Wastewater Treatment and Engineering, 2022
CEPT refers to the process which uses chemicals for coagulation, flocculation, and precipitation of particulate/dissolved solids in the wastewater as a primary step in clarification. Although CEPT was first used around 1840 in France, its use in the US started in the 1960s (Peric et al., 2008). A number of different chemicals were developed, tested, and used. A single chemical or a combination of chemicals can be used. In recent years, CEPT has been used at various wastewater treatment plants for phosphate removal, clarification of wastewater, reduction in sludge volume, and increase in SORs. Increasing the efficiency of primary treatment has dual benefits: (a) It reduces the load for downstream processes, and (b) it enhances the rate of secondary treatment because smaller, easily biodegradable particles are available after primary treatment (Odegaard, 1998). The selection of chemicals for CEPT depends on the primary objective of using them. The dose of chemical coagulant and the method of dosing have to be optimized for better clarification. Chemical coagulants such as ferric chloride are used, together with polymers as flocculating agents. Combined flocculator-clarifiers can be used for this process.
Glycerine Analysis
Published in Eric Jungermann, Norman O.V. Sonntag, Glycerine, 2018
FCC and USP standards call for comparison of glycerine colors with aqueous ferric chloride solution. Typically, a concentrated solution of ferric chloride is made by dissolving excess ferric chloride hexahydrate in 25 volumes of hydrochloric acid and 975 volumes of water. The ferric chloride concentration is calculated iodometrically after appropriate dilution, addition of iodide, and titration of the iodide with thiosulfate. The solution is then diluted with 25 volumes of hydrochloric acid and 975 volumes of water to correspond exactly to 45.0 g/L of ferric chloride.
Chemical Dosage—Jar Testing
Published in Barbara A. Hauser, Practical Manual of Wastewater Chemistry, 2018
The most frequently used coagulant in wastewater treatment, ferric chloride is available in dry and in liquid form, and the reaction is the same as that for alum; the floc is Ferric Hydroxide Fe(OH)3. Ferric chloride is also very acidic, but works well over a wider pH range than alum does. Its primary disadvantage is its strong yellow color which stains – everything.
Effect of solar radiation on natural organic matter composition in surface waters and resulting impacts on drinking water treatment
Published in Environmental Technology, 2023
I. Slavik, D. Kostrowski, W. Uhl
Coagulation jar test experiments were performed according to the Deutscher Verein des Gas- und Wasserfachs (DVGW) [64], with volumes of 1.8 L in 2 L beakers supplied with baffles. Ferric chloride was used as a coagulant. The temperature was kept at 20°C. Considering recommendations by Dennet et al. [65] and Vilgé-Ritter et al. [66] and preliminary experiments, a coagulation pH of 5 was chosen for maximum exploitation of the coagulant. A dosage of 14 mg Fe L–1 or higher had been determined in preliminary experiments to yield maximum DOC removal, and thus the dosage was set to this minimum value. The coagulation pH was adjusted with sodium hydroxide. For instantaneous dispersion of the coagulant and destabilisation of the particles, an Ultra Turrax Disperser (T 25 digital, IKA, Staufen, Germany) was used for the fast-stirring phase (G > 1000 s–1; t = 30 s). Mixing in the following slow-stirring phase (G = 40 s–1; t = 20 min) was performed using a Heidolph RZR 2041 single mixer.
Solvent Extraction of Ti(IV) from Hydrochloric Acid Leaching Solution of Ilmenite
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Figure 13 shows the flowsheet for the manufacture of titanium dioxide of high purity from ilmenite. Leaching of ilmenite with 9 M HCl results in a solution containing Fe(III), and Ti(IV) with small amounts of Mn(II) and Si(IV). According to the result of the ilmenite HCl leaching, Ti(IV) is approximately 80% leached under optimal conditions. The Fe(III) in the leaching solution can be separated by extraction with Alamine 300 and the Fe(III) can be stripped by using distilled water from the loaded Alamine 300. During the extraction of Fe(III), some amount of Ti(IV) was co-extracted into Alamine300. This Ti(IV) in the loaded Alamine300 can be scrubbed by 9 M HCl solution containing FeCl3. Also, loaded Fe(III) in Alamine 300 can be stripped easily using distilled water. Pure ferric chloride can be produced by spray roasting of the obtained Fe(III) solution (Ahmad et al. 2016).
Cellular stress strategies and harvesting methods to improve the feasibility of microalgae biofuel
Published in International Journal of Green Energy, 2022
Luciane Maria Colla, Munise Zaparoli, Francine de Souza Sossella, Naiara Elisa Kreling, Alan Rempel
Aluminum sulfate (Al2(SO4)3) is a low cost product, and is the most used in water treatment. However, wastewater with a high solid content requires a high dosage of Al2(SO4)3 and does not provide an adequate efficiency, which restricts its use. Ferric chloride (FeCl3) is often used in the treatment of effluents as a coagulant because it can operate in a wider pH range when compared to others (between 5 and 11). The disadvantage of using ferrous sulfate (FeSO4.7H2O) is the need for aeration of the medium because the formation of ferrous hydroxide, which is required for harvesting, occurs only in the presence of dissolved oxygen (Nunes 2004).