FATE AND TOXIC EFFECTS OF NITROPHENOLS ON ANAEROBIC TREATMENT SYSTEMS

Modem industrial societies discharge vast quantities of chemicals into the environment Removal of priority pollutants is a vital task of inc reasing importance. A literature search shows that more quantitative i nformation about the effects and fates of these pollutants during anae robic treatment is needed. The objective of this research was to study the fate and toxic effects of nitrophenols (2-nitrophenol, 3-nitrophe nol, 4-nitrophenol and 2,4-dinitrophenol) on methanogenic bacteria. Bo th batch and continuous flow experiments were performed. Batch anaerob ic toxicitys assay (ATA) were performed in methanogenic enrichment cul tures. The effects of 4-nitrophenol were also studied using chemostats at 15-day solids retention time. Stock acetate enrichment cultures we re developed and used in this research. An inhibition coefficient mode l was used to quantify the effects of 1-nitrophenol. The competitive i nhibition coefficient model can adequately describe the fate of the sy stems exposed to 4-nitrophenol. The results of this research showed th at about 81% of 4-nitrophenol can be removed by biodegradation. Among the nitrophenols studied, 4-nitrophenol and 2,4-dinitrophenol were mos t toxic. Copyright (C) 1996 IAWQ.