Mass transfer kinetics of phosphorus biosorption by aerobic granules

The fundamental understanding of mass transfer kinetics is essential for biosorption of phosphorus by aerobic granular sludge (AGS) to gain an insight into biological processes regarding the treatment of wastewater with high organic load. The removal of phosphorus by AGS from palm oil mill effluent was performed in a sequencing batch reactor (SBR) while the experimental data were assessed using the modified mass transfer factor (MMTF) models to get better understanding on the mechanisms of external and internal mass transfer. A zigzag pattern of the [k(L)a](g), [k(L)a](f) and [k(L)a](d) variations was verified before and after addition of Serratia marcescens SA30 due to the variations of organic loading rate and total phosphorus concentration were observed at every additional 50% new sample into the SBR. This study verified that the biosorption process is controlled by transport of phosphorus through a film of external fitting AGS. The analysis of SBR performance shows a logarithmic increase in the efficiency of phosphorus removal with increasing of the [k(L)a](g) value. A new insight of the dynamic AGS growth of biological process revealed by the MMTF models may contribute to the advanced treatment of high organic content wastewater.