1.1本试验方法包括测定水的淤泥密度指数（SDI）。本试验方法可用于指示水中颗粒物的数量，并适用于相对较低（<1.0 NTU）浊度的水，如井水、过滤水或澄清废水样品。由于水中颗粒物的大小、形状和性质可能不同，因此本试验方法不是对颗粒物数量的绝对测量。 1.2本试验方法不适用于规范D1193中试剂级I、II和III类水，或大多数反渗透和超滤系统的废水。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1 SDI可作为水中颗粒物数量的有用指示。 5.2 SDI可用于确定各种过程的有效性，例如用于去除颗粒物的过滤或澄清。 5.3根据经验，SDI与一些水处理设备（如反渗透装置）的结垢趋势相关。 5.4 SDI可能随水温而变化，在不同温度下获得的值可能不一定具有可比性。 5.5 SDI将因膜过滤器制造商而异。因此，使用不同膜制造商的过滤器获得的SDI值无法进行比较。

1.1 This test method covers the determination of the silt density index (SDI) of water. This test method can be used to indicate the quantity of particulate matter in water and is applicable to relatively low (<1.0 NTU) turbidity waters such as well water, filtered water, or clarified effluent samples. Since the size, shape, and nature of particulate matter in water may vary, this test method is not an absolute measurement of the quantity of particulate matter. 1.2 This test method is not applicable for reagent grade water Types I, II, and III of Specification D1193, or effluents from most reverse osmosis and ultrafiltration systems. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 The SDI can serve as a useful indication of the quantity of particulate matter in water. 5.2 The SDI can be used to determine effectiveness of various processes such as filtration or clarification used to remove particulate matter. 5.3 The SDI has been empirically correlated with the fouling tendency of some water treatment equipment such as reverse osmosis devices. 5.4 The SDI may vary as a function of water temperature, and values obtained at different temperatures may not necessarily be comparable. 5.5 The SDI will vary with the membrane filter manufacturer. Thus, SDI values obtained with filters from different membrane manufacturers cannot be comparable.