Factors influencing biodegradation of synthetic organic chemicals in natural and engineered aquatic environments

Synthetic organic chemicals (SOCs) are impacted by biodegradation, sorption, and volatilization in activated sludge wastewater treatment systems. However, when the bioreactor is completely mixed, the effluent concentration is determined by the kinetics of biodegradation. Volatilization and sorption affect only the capable biomass concentration, which is a fraction of the total biomass concentration. Consequently, biodegradation kinetics can be used to characterise quantitatively the biodegradability of SOCs. This paper reviews the factors affecting biodegradation kinetics and methods by which they can be assessed. It also demonstrates how biodegradation kinetic parameters interact with the SOC concentration and the capable biomass concentration to determine the half-life of the SOC in aquatic environments.