Nitrification inhibition test of high salinity wastewater

Nitrification inhibition test is performed to test if the water received by wastewater treatment plant are toxic to the nitrifying bacteria in the WWTP. Standard test method on nitrification inhibition namely, ISO 9509 or modified ISO 9509 method (REFLAB method) could not differentiate the toxicity between salt and toxicant in the sample. Nitrification inhibition test of saline wastewater was tested using salt-adapted nitrifying bacteria grown on biofilm carriers. Results of nitrification inhibition of samples measured with this method were compared with ISO and REFLAB method for real samples and selected specific chemicals. Standard deviation of the new method for nitrification inhibition at the 50% inhibition level was below 3%. Thus, this method is suitable to test the nitrification inhibition of saline wastewater since it differentiate the toxicity between salt and actual toxicants.