Substrate and product inhibition of nitrification

Great effort is paid to the development of new technologies, that enable th e short-cut of the nitrification-denitrification cycle avoiding the oxidati on of NO2- to NO3- (nitrite route). The nitrification of NH4+ only to NO2- and its reduction to gaseous N-2 offers several advantages: lower oxygen de mand for nitrification, lower demand of organic matter for the denitrificat ion of NO2-, higher denitrification rates of NO2- The aim of this work was to obtain more detailed information about the inhi bitive forms (dissociated or nondissociated) of the substrate/product as we ll as about the concentrations that cause inhibition. The substrate-product inhibition was tested in batch tests. Each experiment at a certain pH was carried out using a set of six reactors. One of them served as a reference, while the five others contained different concentrations of the tested com pounds. Five sludges from different municipal wastewater treatment plants w ere used in the experiments. The results obtained from batch inhibition tes ts carried out on different sludges are briefly summarized in this work. Th e very similar behaviour of different sludges is worth to note.