ANSI AWWA B404-14 pdf download.Liquid Sodium Silicate
4.3.2 Product certifications. Liquid sodium silicate is a direct additive used in the treatment of potable water. This material should be certifed as suit- able for contact with or treatment of drinking water by an accredited certifica- tion organization in accordance with NSF/ANSI 60, Drinking Water Treatment Chemicals- -Health Effects. Evaluation shall be accomplished in accordance with requirements that are no less restrictive than those listed in NSF/ANSI 60. Cer- tification shall be accomplished by a certification organization accredited by the American National Standards Institute.
Sec.4.4 Uses
4.4.1 Coagulant aid. To prepare activated silica (which may be used in water treatment as a coagulant aid) from sodium silicate, any one of the following may be used: hydrochloric acid, sulfuric acid, aluminum sulfate, chlorine, or car- bon dioxide together with proper aging and dilution.
4.4.2 Corrosion inhibitor. Sodium silicate may be added to water to reduce corrosion. Sodium oxide and carbon dioxide are partially neutralized, and a fiIm containing silica is deposited on metal surfaces.
4.4.3 Metal sequestering agent. Sodium silicate may be added to water to stabilize reduced iron and manganese ions. The point of addition of the silicate in relation to the point of addition of chlorine or other oxidant is site -specific and should be tested. When silicate is added for this use, corrosion control may also be accomplished.
5.1.2.3 Collection. Three individual samples shall be poured from the freshly mixed composite sample into clean, dry, wide-mouthed plastic containers with plastic-lined screw caps and minimum capacities of 0.5 L. Each sample shall be labeled for identification and the label dated and signed by the sampler.
5.1.2.4 Sample storage. Two samples shall be retained for not less than 30 days after the date of receipt for use by the supplier and the referee laboratory if needed. The samples shall be kept in a cool, dry place and kept covered except when portions are removed for testing. The samples shall be mixed thoroughly before each portion is removed.ANSI AWWA B404-14 pdf download.