In an Imhoff cone test, settleable solids are recorded in which measurement?

In an Imhoff cone test, settleable solids are specifically measured in milliliters per liter (ml/l). This method is used to evaluate the volume of solids that can settle out of wastewater over a specified period, typically 30 minutes.

The volume measurement in ml/l allows for a clear understanding of how many milliliters of solids settle when one liter of wastewater is allowed to stand. This is important for assessing the performance of a wastewater treatment system, as it indicates the concentration of settleable solids present in the influent or effluent.

Other measurement units, such as grams per liter (g/l), parts per million (ppm), and milligrams per liter (mg/l), are used in different contexts or for different types of analyses. For instance, g/l might be used for total solids, while mg/l and ppm are commonly used for concentrations in water quality assessments, but neither provides the same direct volume measure of settled solids as ml/l does in the context of the Imhoff cone test.