Which of the following are removed through the secondary water treatment process?

Secondary treatment uses microbes to remove colloidal and dissolved organic matter from wastewater.

Polythene and tetra packs are gross solids taken out by screening before any treatment stage.

Large suspended solids settle out during primary, not secondary, treatment.

Settleable organic matter is also removed in the primary sedimentation stage.

Biological breakdown of dissolved organics is what defines the secondary stage.

Tertiary treatment then removes the remaining nutrients and dissolved solids.