Denitrification of high concentrations of nitrites and nitrates in synthetic medium with different sources of organic carbon. II. Ethanol.

The course of denitrification of nitrites and nitrates (1000 mg N/l) in medium containing ethanol as a source of organic carbon was studied. Continuous cultures of a mixed population of autochtonous microflora isolated from the bottom sludge of a nitrogenous wastewater reservoir were set up in two types of culture units: chemostat-type column and anaerobic packed bed reactor. In medium with nitrites denitrification was found to be strongly inhibited by alkalization of the medium (efficiency of denitrification 17.7 mg N/l/h). When pH was adjusted the efficiency of nitrite denitrification was identical as for nitrates (166.3 mg N/l/h). The denitrification of 1 g of nitrate or nitrite nitrogen was found to require 2.00 and 1.28 g ethanol, respectively.