Denitrification of Sodium Nitrate by Means of Mixed Culture of Microorganisms: (Part II.)

L. Tomerlin, L. Dvoraček and V. Bešlić

Abstract
This paper describes the reduction of nitrate (denitrification) from sodium nitrate in a synthetic medium by means of a mixed culture of microorganisms. Mixed culture was applied in experiments of oxidation of ammonia from ammonium sulphate (Part I). It was adapted to degrade nitrate in substrate with and without carbon source. The degradation of nitrate mass concentration of 0.20 g L-1 and 0.60 g L-1 was carried out in 0.5 L of synthetic medium in aerated reactor after adding one of carbon source: glucose, 3-Na-citrate, Na-acetate or methanol ζ/C/N=6:1). The initial pH value was 5.5 or 7.5 and during 18 or 24h of degradation the temperature in reactor was 23 oC. In both cases mixed culture of microorganisms reduced nitrate up to 99 % and accumulation of nitrite was low (3.88 mg L-1). The exception was the sample at pH value 7.5 with Na-acetate added as the source of carbon (up to 11 mg L-1).

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Keywords
Aerobic degradation, sodium nitrate, mixed culture of microorganisms, carbon source