Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

Experimental protocols to identify and quantify nitrogen nutrient deficienc y in the activated sludge process were developed and tested using respirome try. Respirometric experiments showed that when a nitrogen nutrient deficie nt sludge is exposed to ammonia nitrogen, the. oxygen uptake rate (OUR) of the sludge increases while an initial nitrogen nutrient uptake takes place at the same time. Our investigation suggests that this initial nitrogen upt ake is metabolically mediated. The protocols developed in this study can be used: (a) to assess whether a sludge sample is nitrogen nutrient deficient or not; and (b) to estimate the amount of nitrogen required to remedy a nu trient deficient condition in the sludge. Finally, a respirometry-based str ategy to control nutrient addition to the activated sludge process is propo sed. (C) 2000 Published by Elsevier Science Ltd.