Fate of organic bases during Biooxidation of coal carbonization wastewater

Abstract

Low temperature and high temperature coal carbonization processes generate wastewaters containing ammonia, phenols, organic bases, viz. pyridine, alpha picolines, beta picolines, lutidine, quinoline and aniline. Most of the biological treatment processes employed for the treatment of the coal carbonization wastewater are evaluated and monitored for the removal of ammonia and phenols. The organic bases being pollutants of environmental concern, their status in the treatment units should be monitored. In the present investigation the fate of the organic bases has been evaluated in two stage activated sludge process employed for the treatment of coal carbonization wastewater. In the first stages of activated sludge process, the bases, viz. pyridine, picolines, and lutidine do not get removed effectively even at high sludge retention time (SRT) of 10.9 days. The poor removal of bases in the first stage of activated sludge process unit may be attributed to the residual phenol concentration of more than 5 mg/L in the first stage of bioreactor and preferential utilization of phenols over organic bases. In the second stage of the activated sludge process most of the bases get removed efficiently at SRT of 12 days. On employing a two stage activated sludge process, the bases from coal carbonization wastewaters could be removed effectively by operating first stage at SRT of 2.18 days and the second stage of the process at 12 days SRT respectively.