Mitigating Ammonia Pollution in Water - Can There Be Any Suitable Coagulant?

Dear Friends, I am working on a research plan to mitigate ammonia pollution in water with the help of a desert plant extract (Yucca). I have taken its stem and powdered. This powder reduces ammonia in water but the residue/ turbidity/ colloidal particles that it leaves in water do not get settled by any coagulant like Alum, PACl, FeCl3, Tanfloc and ZnSO4. What should I use to coagulate the colloidal suspension in water? Meanwhile, I have also got a leachate sample collected from Delhi which also does not get coagulated by any mean. Please, advice / suggest some way. Regards Lokesh Kumar Chartered Chemist, Delhi, India