HIGH-CONCENTRATION NITRITE-OXIDIZING BACTERIUM, AND METHOD FOR HIGH-CONCENTRATION CULTURE OF NITRITE- OXIDIZING BACTERIUM

摘要

PROBLEM TO BE SOLVED: To provide a method for culturing in large quantities and in high concentrations nitrite-oxidizing bacteria in nitrifying bacteria contained in activated sludge. SOLUTION: The method for culturing in high concentrations nitrite-oxidizing bacteria in nitrifying bacteria slightly contained in activated sludge including sewage sludge and excrement sludge comprises the following process: activated sludge is subjected to nitrifying acclimatization by feeding an NH4-N-containing liquid in a dissolved oxygen concentration of >=2 mg/L at pH 7.0-9.0 and 20-40 deg.C for a specified period, and the pH of the system tending toward acidic side during the acclimatization step is maintained within the above-mentioned range by incorporation of a culture promoter consisting of a mixture of sodium carbonate and sodium bicarbonate to effect the acclimatizing accumulation of the ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in the nitrifying bacteria contained in the activated sludge; thereafter, feed of the NH4-N-containing liquid is stopped and an NO2--containing liquid is fed instead to decrease the number of the ammonia-oxidizing bacteria, and the nitrite-oxidizing bacteria are further subjected to acclimatizing accumulation.