I suggest the following ...

I suggest the following steps:

1. Remove ammonia from the wastewater via biological nitrification

2. Anaerobically digest the excess biomass from biological nitrifiation to release ammonia into the water in the digester.

3. When excess digested biomass is dewatered, retain the filtrate from the dewatering process.  It should contain > 1000 mg/L of ammonia.

4. Recover the ammonia from the filtrate via distillation such as used by the company ThermoEnergy.  Their CASTion process recovers the ammonia as concentrated ammonium sulfate that can be used for fertilizer.

Struvite precipitation is another alternative but only removes ammonia to the extent of phosphate present.  The above suggested approach could be used in conjunction with and following struvite preciptation.