Studies on nitrification of aniline with acclimated activated sludge

Aniline, a toxic, organic pollutant, occurs in a number of industrial effluents. Apart from carbonaceous oxygen demand, aniline imposes a nitrogenous oxygen demand, due to its nitrogen content, in excess of that required for cell growth. Incomplete biodegradation will result in ammonia production; this also exerts toxicity. Hence, nitrification of aniline should be ensured in the biological treatment before discharge into receiving streams. Aniline, however, is reported to inhibit the nitrification process. Aniline degradation was studied in laboratory continuous activated sludge with an acclimated culture developed in synthetic feed to determine the extent of complete biological degradation. Aniline-N (even at 400 mg/L aniline concentration)could be converted to nitrate-N with ammonium-N and nitrite-N formed as intermediates at a detention time of 24 h. The nitrification, however, was suppressed by aniline. The degradation of aniline to ammonia releases the suppression and the nitrification proceeds rapidly.