Investigation on biological treatment of para-nitrophenol contaminated water and the effective factors

Widespread use of para-nitrophenol (PNP) for drug, pesticides manufacturing and dyestuff production has made PNP as an important pollutant in industrial wastewater streams. In this study, four bacterial and three fungal species have been examined for their efficiency towards PNP degradation. At initial PNP of 50mgl-1, Aspergillus terrus with 70% PNP removal was found as the superior fungi, while it could not tolerate 100mgl-1 PNP. For bacterial strains, experiments were carried out to compare PNP degradation at 50mgl-1 (0.05% glucose as co-substrate), among which Alcaligenes faecalise showed the highest PNP biodegradation of 21%. Increased amount of glucose to 0.1% resulted in an increase in growth, however, prolonged lag phase in biodegradation was observed. Alternate nitrogen sources i.e. yeast, sodium nitrate and ammonium sulfate each at 0.01% were tested (0.05% glucose as co-substrate) where yeast resulted in the maximum PNP degradation. Increased amount of yeast to 0.1% led to 57% PNP biodegradation. Inhibitory effect of PNP at 100mgl-1 PNP was studied at the optimum concentrations of glucose and yeast showing decreases in both growth and biodegradation. However, 38% PNP removal was still obtained while Aspergillus terrus could not tolerate this high PNP concentration.

Keywords:

Alcaligenes Faecalise , Aspergillus Terrus , Biodegradation , Nitrophenol , Wastewater Treatment