1. Phosphate removal from aqueous solution with Fly Ash and Natural Zeolite S. Safari1, D.F.E. Galarza1, Dr. E. Katsou1, Dr. S. Malamis2  1Department of Mechanical, Aerospace and Civil Engineering, Brunel University London, UK. 2Department of Water Resources and Environmental Engineering, National Technical University of Athens, Greece
Introduction
Results
Conclusion
Phosphorus (P) is an essential element to all life forms and is currently under source stress as economically relevant P ore reserves are limited
There are predictions that rock P will be exhausted within 75 years
The water industry has the potential to fulfil part of the P demand since a high percentage of all the P used ends up in the wastewater treatment plants (WWTPs), (England alone is estimated to have 41.4 tons of P ending up in the sewers per year).
The Phosphorus cycle today
Z-N does have an efficient phosphates sorption capacity.
The phosphate removal rate increases along with the increment of the Z-N and Z-Fe concentration
The obtained results for the removal rates and adsorption capacities of FA suggest that the material is not suitable to remove phosphates from aqueous water
High removal rates are achieved when the initial or adjusted pH of the aqueous solution is between the values of 4 and 7
A balance point between the adsorption capacity of the material at equilibrium (qe) and the adsorption rate (K’) was identified to be when the C0/AC value is 2.0 mg/g.
Figures A and B : Graphs illustrate various concentrations of Z-N and Z-Fe in the phosphate removal efficiency and the adsorption capacity (10 mg PO4-P/L, pH=7). A B
Average Removal
Figure C : Graph shows the effect of different FA concentrations in the phosphate removal efficiency for initial PO4-P concentrations of 10, 75 and 100 mg/L (pH=7).
Future work C
Determine phosphate adsorptive behaviour of Z-Fe under different water quality conditions, such as ionic strength
Life cycle assessment (LCA) of using the different adsorptive materials should be done to define the environmental impacts of the entire process.
Column experiments to determine the performance of the material under dynamic conditions.
Motivation
To develop a process for the
removal and recovery of P from
secondary effluents in WWTPs
To use low-cost minerals such
as Fly Ash (FA) and Natural
Zeolite (Z-N).
References
Figure D: Graph shows an overview of different adjusted pH values on the phosphate removal rate and the real adjusted aqueous pH of the solution in time (10 mg/l PO4-P/L and 5g Z-N/L)
Figure E: Graph shows Phosphate adsorption capacity and rate onto Z-Fe for different phosphate concentration adsorbent concentration ratio (C0/AC).
Weiner ER. Applications of environmental aquatic chemistry: a practical guide. : CRC press; 2012
De Gisi S, Lofrano G, Grassi M, Notarnicola M. Characteristics and adsorption capacities of low-cost sorbents for wastewater treatment: A review. Sustainable Materials and Technologies ;9:10-40
Kroiss, H., M. Zessner (2007). Ecological and economical relevance of sludge treatment and disposal options. Proceedings of the Conf. Moving Forward Wastewater Biosolids Sustainability, Technical Managerial and Public Synergy, New Brunswick, Canada.
Future Phosphorus Cycle
Methodology E D
Batch adsorption experiments.
Examination of different parameters:
Effect of Adsorbent Dosage
Effect of pH
Effect of Initial phosphate concentration
Z-N, FA and modified Zeolite with Iron (Z-F) were selected as a sorbent material to remove
Batch test
Batch test