Ahmed, Ammonia is highly ...

Ahmed, Ammonia is highly toxic to aquatic life, particularly larvae, so the best solution for the environment as a whole would be to tackle the pollution at source if possible. Find the ammonia discharges into the river and sort them out first.

If this is not feasible, you can use aerated sand filters to remove both solids and ammonia simultaneously. It is like a conventional sand filter but operated in a way to deliberately allow a thin biofilm of nitrifiers to develop.