Abstract
It has been demonstrated that blast furnace slag (BFS) has high P adsorption capacity. Steel furnace slag (SFS) has similar physical and chemical properties to BFS, but whether the former has similar P adsorption characteristics to the latter is unclear. In order to assess its reuse potential as main filter media in treating phosphorus-rich farmyard wastewater, the phosphorus adsorption isotherm of SFS in high-P solution was derived and the adsorption process was examined as a function of pH; then, SFS was used as a main substrate in a tidal flow reed bed system and its treatment performance was evaluated to determine the removal efficiency of COD, BOD5, SS, TN and PO4-P during farm wastewater treatment process. Compared with Freundlich and Tempkin isotherm, Langmuir model yielded the best fit for the SFS. The maximum adsorption capacity reached 27.8 mg P/g at an optimum pH of 4.0. Our results show that SFS reed bed may be a novel effective system to wipe off phosphorus from wastewater, and then it may also provide an approach for the reuse of SFS.
Acknowledgements
The authors would like to thank Science and Technology Department of Henan Province for financial support of this study (Grant No. 082102330006).