Phosphates & Surfactant in WWTP

Dears,

I am trying to find an ideal solution for my plant. The WWTP ( domestic ) is having phosphates of 20 ppm & need to guarantee outlet of < 1 mg/l. Moreover , surfactant existed in the plant & is required to be removed. What would be ideal for phosphates removal , 

a. Having anaerobic tank a head of biology ( with about 0.5-1 hour retention time ). What would be the expected removal efficiency to achieve?

b. Primary settling with coagulation of Iron Salt or Alum. Again , any idea of design basis for settling tank as well as the dosage? What would be the expected removal efficiency to achieve?

Regarding surfactant , would the usage of the primary settling along with coagulant enhance the removal? What would be the expected removal efficiency to achieve?

Any suggestions/recommendations?

Thanks

Dania