AWWA B404-14 pdf download.Liquid Sodium Silicate
4.3.2 Product certifcations. Liquid sodium silicate is a direct additive used in the treatment of potable water. Tis material should be certifed as suit- able for contact with or treatment of drinking water by an accredited certifca- tion organization in accordance with NSF/ANSI 60, Drinking Water Treatment Chemicals—Health Efects. Evaluation shall be accomplished in accordance with requirements that are no less restrictive than those listed in NSF/ANSI 60. Cer- tifcation shall be accomplished by a certifcation organization accredited by the American National Standards Institute.
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 flm 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. Te point of addition of the silicate in relation to the point of addition of chlorine or other oxidant is site-specifc and should be tested. When silicate is added for this use, corrosion control may also be accomplished.
5.1.2.3 Collection. Tree 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 identifcation 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. Te samples shall be kept in a cool, dry place and kept covered except when portions are removed for testing. Te samples shall be mixed thoroughly before each portion is removed.AWWA B404-14 pdf download.