WEF Discussion Forums
Biological Nutrient Removal
High influent TKN
We have experienced unusual domestic wastewater characteristics, influent TKN ~ 150-200mg/L and Influent BOD ~ 700mg/L. Whilst we are trying to identify where the cause of this strange wastewater, the effluent nitrate keeps iincreasing!
Despite the sludge age is 40 days (a MBR), high recycle ratio in bardenpho process (4x Recycle) and molasses dosing for the right C/N ratio, the effluent total nitrogen is around 25mgN/L (Ammonia of 2 and the rest is nitrate). The nitrate target is 10mg/L!
Have someone else encountered similar situations before and what could be done to control this?
Also, is there such a theory of denitrification inhibition?
What were your TKN numbers before this increase. Those numbers are higher than I have ever seen in any facility. Have you tested your trunk lines for TKN or ammonia. If you are able to convert that much ammonia, the nitrate numbers before denitrification must be extremely high. You will be hard pressed to convert that much nitrate to N because the carbon necessary has detrimental affects, such as high oxygen demand.