
%0 Journal Article
%A Mann, R. A. 
%T Phosphorus adsorption and desorption characteristics of constructed wetland gravels and steelworks by-products
%J Soil Research
%D 1997/03/05
%V 35
%N 2
%P 375-384
%K phosphate adsorption capacities, Langmuir and Freundlich isotherms, steelworks by-products, constructed wetlands substrata.
%R https://doi.org/10.1071/S96041
%U https://www.publish.csiro.au/paper/S96041 
%X Laboratory phosphorus (P) adsorption and desorption experiments were conducted on 9 substrata to evaluate their potential to remove P from sewage effluent. The substrata comprised 2 gravels used in constructed wetlands, Hawkesbury sandstone, and 6 steelworks by-products: granulated blast furnace slag, blast furnace slag, steel slag, fly ash, bottom ash, and coal wash. The studies involved ion-exchange experiments and calculation of Langmuir and Freundlich adsorption isotherms and column adsorption/desorption trials. The ability to adsorb P was then correlated to the physico-chemical attributes including X-ray fluorescence analyses of each substratum. High P adsorption capacities (&#62;380 mg/kg) were shown for granulated blast furnace slag, blast furnace slag, and steel slag, as well as fly ash. All steelworks by-products had adsorption capacities greater than the constructed wetland gravels and Hawkesbury sandstone. The P adsorption capacities of the substrata were significantly correlated with Ca (r2 = 0 &#183; 9206), Mg (r2 = 0 &#183; 8681), pH (r2 = 0 &#183; 7009), S (r2 = 0 &#183; 6696), and Si (r2 = 0 &#183; 6438) when fly ash was omitted from the analyses. Further research is recommended to evaluate the sustainability of using slags for P removal (as well as other contaminants present in wastewater), using full-scale constructed wetlands. Research should include an evaluation of any likely environmental impacts using leachability and toxicity studies. 
