Liquid Alum Feeding & Properties

Properties of Liquid Alum

Specific Gravity, (g/mL) 1.0069 1.0140 1.0211 1.0284 1.0357 1.0432 1.0507 1.0584 1.0662 1.0741 1.0821 1.0902 1.0985 1.1069 1.1154 1.1240 1.1328 1.1417 1.1508 1.1600 1.1694 1.1789 1.1885 1.1983 1.2083 1.2185 1.2288 1.2393 1.2500 1.2609 1.2719 1.2832 1.2946 1.3063 1.3182 1.3303 1.3426 1.3551 1.3679

lb/gal 8.40 8.46 8.52 8.58 8.64 8.70 8.76 8.83 8.89 8.96 9.02 9.09 9.16 9.23 9.30 9.37 9.45 9.52 9.60 9.67 9.75 9.83 9.91 9.99 10.08 10.16 10.25 10.34 10.43 10.52 10.61 10.70 10.80 10.89 10.99 11.09 11.20 11.30 11.41

%Al2O3 0.19 0.39 0.59 0.80 1.01 1.22 1.43 1.64 1.85 2.07 2.28 2.50 2.72 2.93 3.15 3.38 3.60 3.82 4.04 4.27 4.50 4.73 4.96 5.19 5.43 5.67 5.91 6.16 6.42 6.67 6.91 7.16 7.40 7.66 7.92 8.19 8.46 8.74 9.01

Equivalent % Dry Alum 1.12 2.29 3.47 4.71 5.94 7.18 8.41 9.65 10.88 12.18 13.41 14.71 16.00 17.24 18.53 19.88 21.18 22.47 23.76 25.12 26.47 27.82 29.18 30.53 31.94 33.35 34.76 36.24 37.76 39.24 40.65 42.12 43.53 45.06 46.59 48.18 49.76 51.41 53.00

Dry Alum per Gallon Solution (lb) 0.09 0.19 0.30 0.40 0.51 0.62 0.74 0.85 0.97 1.90 1.21 1.34 1.47 1.59 1.72 1.86 2.00 2.14 2.28 2.43 2.58 2.74 2.89 3.05 3.22 3.39 3.56 3.74 3.93 4.12 4.31 4.51 4.71 4.91 5.12 5.34 5.57 5.81 6.05

Dry Alum per Liter solution (g) 11.277 23.221 35.432 48.438 61.521 74.902 88.364 102.136 116.003 130.825 145.110 160.368 175.760 190.830 206.684 223.451 239.927 256.540 273.430 291.392 309.540 327.970 346.804 385.841 385.931 406.370 427.131 449.122 472.000 494.777 517.027 540.484 563.539 588.619 614.149 640.938 668.078 696.657 724.987

*17% AL2O3 in dry alum +0.03% free AL2O3 www.inyoprocess.com Liquid Alum Specific Gravities & Concentrations WP-1018 dtd 1/06

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Alum Addition for Stock Solutions Solution (%) 0.1 0.2 0.5 1.0 1.5 2.0

Concentration (mg/L) 1,000 2,000 5,000 10,000 15,000 20,000

mg of Alum Added to 1-L Flask 1,000 2,000 5,000 10,000 15,000 20,000

Preparation of an Alum Feed Solution 1. Determine the desired percent solution for feeding the alum (Typically a 10 to 20 percent solution used. for this example, let’s assume a 15% solution). 2. Based on the volume of alum solution to be prepared, determine the weight of alum to add to the solution tank. For an alum solution volume of 1000 gallons, determine the alum weight as follows: Alum Weight = 1000 gal x 8.34 lb/gal x 0.15 = 1,251 lb

General Comments When Dosing Alum Alum (aluminum sulfate) is a commonly used coagulant in water treatment. Adding alum to water creates insoluble precipitates such as aluminum hydroxide AI(OH)3 to form. The optimum pH range for alum coagulation is 5 to 8. Alkalinity must be present for the alum reaction to work effectively. If there is insufficient alkalinity in the raw water, the pH will be lowered to a point where soluble aluminum ion is formed instead of aluminum hydroxide. If soluble aluminum is present, this can cause problems in the distribution system and clear well from post flocculation. Typically 1.0 mg/L of commercial grade alum will consume about 0.5 mg/L of alkalinity. www.inyoprocess.com Liquid Alum Specific Gravities & Concentrations WP-1018 dtd 1/06

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At least 5 to 10 mg/L of alkalinity should remain after the reaction to maintain optimum pH. 1.0 mg/L of alkalinity (in the form of CaCO3), is equivalent to: 0.66 mg/L of 85% quicklime (CaO) 0.78 mg/L 95% hydrated lime (Ca(OH)3) 0.80 mg/L caustic soda (NaOH) 1.08 mg/L soda ash (Na2(CO)3) 1.52 mg/L sodium bicarbonate (NaHCO3) If additional alkalinity is needed it should be added before adding the coagulant and thoroughly mixed. When mixing alum with water to make a feed solution, confirm that the pH is below 3.5 to prevent hydrolysis—Hydrolysis will reduce the effectiveness of the alum coagulant. A 10 to 20 percent alum solution by weight will maintain this pH requirement in most applications.

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3 of 3 Although every attempt has been made to provide accurate and reliable information in this guide, Inyo Process cannot and does not assume responsibility or liability in respect to its use.