Which of the following are colloidal material in domestic waste?

The correct answer is Option (2) → Fecal matter and bacteria

Suspended solids, such as sand, silt, and clay, remain suspended in water.

Colloidal materials consist of microscopically dispersed insoluble particles ranging from 0.001 to 1 micrometers in size. Examples include fecal matter, bacteria, cloth, and paper fibers.

Dissolved materials, found in domestic sewage, include nutrients like nitrates, ammonia, phosphate, and sodium.

                                Composition of waste water