The biological degradation of multiple substrates was studied at room temperature in aerated 5-liter batch reactors using mixed liquor from the Passaic Valley Sewerage Commissioners wastewater treatment plant (Newark, New Jersey).

Two substrate mixtures were used (with initial concentration indicated in parenthesis): (1) phenol(100ppm) + nitrobenzene(10ppm) + 2,6-dichiorophenol(10ppm); (2) 2-chlorphenol(20ppm) + nitrobenzene(10ppm) + 2,6-dichlorphenol(10ppm). From concentration versus time data, kinetic rate constants for zero-order, first-order, and Monod models were determined. Most of the data were best fit by either the Monod or zero-order model. For all compounds tested biodegradation was the primary removal mechanism, and in many cases the rate of biodegradation was significantly faster than those measured when the individual compounds were the sole Carbon source.