title: Effects of chemical amendments on the lability and speciation of metals in anaerobically digested biosolids.
abstract: The interaction of inorganic contaminants present in biosolids with iron, aluminum, and manganese oxy/hydroxides has been advocated as a key mechanism limiting their bioavailability. In this study, we investigated whether this is indeed the case, and further, whether it can be exploited to produce optimized biosolids products through the addition of chemical additives during sewage sludge processing. Experiments were conducted to investigate whether the addition of iron- and aluminum-based amendments (at 5 different rates) during the anaerobic digestion phase of wastewater treatment can effectively change the speciation or lability of contaminant metals (copper, zinc and cadmium) in biosolids destined for use in agriculture. The performance of the bioreactors was monitored throughout and the speciation and lability were determined in both fresh and 3-month aged biosolids using X-ray absorption spectroscopy (Cu, Zn) and isotopic dilution ((65)Cu, (65)Zn, (109)Cd). The tested amendments (FeCl3, Al2(SO4)3, and Al-rich water treatment residual) did not cause significant changes in metal speciation and were of limited use for reducing the lability of contaminant metals in good quality biosolids (suitable for use in agriculture), suggesting that high affinity binding sites were already in excess in these materials. However, the use of chemical amendments may offer advantages in terms of treatment process optimization and may also be beneficial when biosolids are used for contaminated site remediation.
authors: Centre for Environmental Risk Assessment and Remediation, University of South Australia , Building X, Mawson Lakes Campus, Mawson Lakes,South Australia 5095, Australia.
authors: Erica
authors: E
authors: Donner
authors: Gianluca
authors: G
authors: Brunetti
authors: Bernie
authors: B
authors: Zarcinas
authors: Paul
authors: P
authors: Harris
authors: Ehsan
authors: E
authors: Tavakkoli
authors: Ravi
authors: R
authors: Naidu
authors: Enzo
authors: E
authors: Lombi
mesh_terms: D000534:Alum Compounds / Q000494:pharmacology*; D000693:Anaerobiosis; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D019149:Bioreactors; D002712:Chlorides / Q000494:pharmacology*; D005290:Ferric Compounds / Q000494:pharmacology*; D008670:Metals / Q000737:chemistry* / Q000378:metabolism; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid
chemical_list: D000534:Alum Compounds; D002712:Chlorides; D005290:Ferric Compounds; D008670:Metals; D012722:Sewage; C041524:aluminum sulfate; C024555:ferric chloride