Which Statement Does NOT Apply to Water Treatment

Which statement does NOT apply to water treatment?

A) The primary treatment of wastewater is a physical process designed to remove materials that settle out. 
B) Advanced treatment of wastewater is often designed to remove ammonia, nitrates, and phosphates.
C) Biosolids that result from anaerobic digestion of sludge can be used to improve soils and promote plant growth.
D) Secondary treatments are designed to convert suspended solids into inorganic compounds and microbial biomass.
E) An important goal of wastewater treatment is the increase of the BOD that stimulates microbial growth.