Sorption of Ammonia Nitrogen on River Borne Suspended Solids

The ammonia nitrogen carrying capacity of Wabash River suspended solids was evaluated. The sorption of ammonia onto these solids was found to follow a Langmuir model and to be reversible. At background river ammonia concentrations of below about 0.2 mg l⁻¹, sorbed ammonia carried by the suspended solids is quite low, less than 0.2 mg NH₃-N per gm suspended solids. However, near outfalls under the right conditions, as much as 15 to 20% of the ammonia discharged may be initially sorbed from solution to be later released downstream when the soluble ammonia concentration decreases.