P-nitrophenol degradation by activated sludge attached on nonwovens.

p-Nitrophenol (PNP) is a toxic compound that enters the environment during manufacturing and processing of a variety of industrial products. This study demonstrates the use of inexpensive and durable nonwovens as a biomass retainer for the biological degradation of p-nitrophenol. An essential aspect of p-nitrophenol degradation was the cultivation of p-nitrophenol degrading biomass prior to its attachment on the nonwovens. Results of continuous flow experiments demonstrated that using the nonwovens could attain consistent high-rate p-nitrophenol degradation. 500 mg-PNP/L was completely degraded at a hydraulic retention time of 11 h. Specific and volumetric p-nitrophenol loading rates were determined to be 165 mg-PNP/g-MLSS/d and 1.6 g-PNP/L/d, respectively. Nitrite released from p-nitrophenol breakdown was not completely nitrified to nitrate. Characteristics of p-nitrophenol degrading sludge were also investigated.