An examination of the adsorption characteristics of various pharmaceuticals on to live activated sludge system

In this study, the removal properties of several anti-inflammatory pharmaceuticals such as diclofenac, paracetamol, ibuprofen and naproxen through the adsorption by live activated sludge were investigated in a batch system. Each pharmaceutical was found to be adsorbed by the live activated sludge at various rates. It was found that the adsorption took place substantially at the first 20 to 40 minutes of the contact time and reached steady-state within 80 minutes for all pharmaceuticals tested. Removal rates varied between 40-79% for all pharmaceuticals examined. Results obtained from the equilibrium experiments have been applied to both Langmuir and Freundlich isotherm models and data fitted better to Freundlich isotherm model compared to Langmuir model for all pharmaceuticals. The kinetics of the adsorption were also investigated and it was found that the adsorption rates were best described by the pseudo second order model. Sorption coefficient, Kd, which describes the solid liqiud partitioning charecteristics of a compound in sorption mechanism were also calculated for each pharmaceutical.