AWWA B402-18 pdf download.Ferrous Sulfate
4.3.1 General. The material supplied according to this standard shall contain no soluble inorganic or organic substances in quantities capable of producing deleterious or injurious effects on the health of those consuming water that has been properly treated with the material. Dried ferrous sulfate shall contain no detergent compound or sequestering agent. In addition, the ferrous sulfate supplied shall not contain any substances in quantities that will result in treated sludges that will be designated as hazardous wastes by local, state, provincial, or federal authorities.
4.3.2 Product certifications. The material is a direct additive used in the treatment of potable water. This material should be certified as suitable for contact with or treatment of drinking water by an accredited certification organization in accordance with NSF/ANSI 60. Evaluation shall be accomplished in accordance with requirements that are no less restrictive than those listed in NSF/ANSI 60. Certification shall be accomplished by a certification organization accredited by the American National Standards Institute.
5.2.2.1 Moist or dried ferrous sulfate. Test samples of moist or dried ferrous sulfate shall be obtained from one of the three material samples. The dried ferrous sulfate sample shall be divided into two samples, one of 150–200 g for physical screen size determination and a second of approximately 100 g for the chemical analyses. The sample for physical screen size shall be used for the sieve analysis (Sec. 5.2.3). The sample for chemical analyses shall be reduced by either mechanical grinding or in a mortar by hand to such fineness that all of it passes through a No. 30 US Standard Sieve. These operations shall be carried out rapidly to minimize the change in moisture content of the sample. After thorough mixing, the sample for chemical analyses shall be stored in an airtight glass container.
Stannous chloride reduction method: To the solution, add 10 mL of hydrochloric acid and heat to boiling. Add the stannous chloride solution by drops until the last trace of greenish-yellow color disappears. Then add one additional drop in excess to ensure complete reduction. Cool to 20°C, add 60 mL of deionized water, and then add, in one pouring, 20 mL of saturated mercuric chloride solution with agitation to ensure instantaneous mixing. If a white, milky precipitate forms, add 30 mL of 25 percent phosphoric acid solution and 7 to 10 drops of diphenylamine barium sulfonate indicator. The volume of the solution should be between 150 and 200 mL. If a dark precipitate forms, there is too much stannous chloride. If no precipitate forms, there is too little stannous chloride. In either case, the entire procedure must be repeated on a new sample.AWWA B402-18 pdf download.