In waste water treatment, biological processes are employed to remove mainly which of the following?

Biological treatment mainly removes colloidal matter and soluble organic compounds.

Statement 1, bacteria, are the agents of treatment, not the target removed.

Statement 2, suspended solids, are taken out by physical settling and screening.

Statement 3, fungi, are not the principal target of biological wastewater treatment.

Statement 4, colloidal matter, is broken down and removed by microbial action.

Statement 5, soluble organic compounds, are consumed by microbes as food.

Microorganisms convert dissolved organics into settleable biomass and gases.