Nitrification/denitrification in nitrogen high-strength liquid wastes

Abstract To evaluate the possibility of nitrogen removal from nitrogen high-strength wastewaters, nitrification rates, denitrification and related energy problems, emerging in nondiluted wastewater from a pig production plant, are studied on a laboratory level. Excess nitrogen can be removed by utilising a nitrification process first and a denitrification process afterwards, and so reduce the content of residual mineral nitrogen to less than 100 mg l −1 . Oxidation of ammonium, the most critical phase, is carried out with an inoculum of nitrifying bacteria adapted to the wastewater type under adequate aeration, and carefully controlled pH. The dilution of wastewater is not needed, nor external organic carbon to reduce nitrate.