Trickling filter system for biological nutrient removal

摘要

The present invention provides a two stage process for treating wastewater that subjects the influent to anoxic and oxic filtering processes. The first stage performs anoxic nitrification i.e., the conversion of nitrate to nitrogen gas by bacteria operating in the absence of oxygen. Influent (effluent from the primary clarifiers) is fed into the bottom of the anoxic dentirification tank, preventing contact with the atmosphere and thus reducing the amount of unwanted dissolved oxygen. The influent passes upwards through a layer of sludge biomass before contacting bacteria coated media which performs the denitrification process. This arrangement permits the influent to contact the sludge and the biomass to circulate through the filter, enhancing deoxygenation and the performance of the system.