Biodegradation of 2,4-dichlorophenol by activated sludge microorganisms

Abstract

Experiments with the degradation of 2,4-dichlorophenol (2,4-DCP) were carried out in completely-mixed systems at constant volumetric loading ( B v) and variable solids retention time (SRT). A mixed substrate consisted of 2,4-DCP (20% of total COD) and methanol (MA, 80% of total COD). The maximum specific rate of 2,4-DCP removal, q max, related to the total biomass in the cultivation system, increased with the decreasing SRT from 0.0118 h −1 at the SRT of 10.8 d up to 0.0783 h −1 at the SRT of 0.6 d. The following values of kinetic constants of microorganisms responsible for the degradation of 2,4-DCP were found (20°C and pH = 7.5): Y COD = 0.37, K s,COD = 0.6 mgl −1, q max = 0.233 h −1, b = 0.036 h −1, μ max = 0.086 h −1 and π x,cr = 0.83 d.