Degradability of five aromatic compounds in a pilot wastewater treatment system

Purified terephthalic acid-manufacturing wastewater was treated aerobically with the microbial fusant Fhhh in the carrier activated sludge process at a pilot wastewater treatment plant. Biodegradability of p-toluic acid (p-Tol), benzoic acid (BA), 4-carboxybenzaldehyde (4-CBA), phthalic acid (PA) and terephthalic acid (TA) was monitored. The TOC and COD loading rate of suspended solids (SS) in the sludge were 0.53 g TOC g SS−1 d−1 and 1.79 g COD g SS−1 d−1, respectively. There was significant positive correlation (P<0.05 or 0.01) between the manganese peroxidase specific activity and the sludge loading rates of aromatics except for PA. The data suggest that the biodegradation of the aromatic compounds monitored followed the order: BA>PA>4-CBA>TA>p-Tol. The prospect of using MnP-SA to predict the removal rate for the five aromatics is discussed.