title: Effect of Ethylenediamine-N,N'-disuccinic acid (EDDS) on the speciation and bioavailability of Fe2+in the presence of sulfide in anaerobic digestion.
abstract: The effects of a biodegradable chelating agent, Ethylenediamine-N,N'-disuccinic acid (EDDS), on the speciation and bioavailability of iron (Fe2+) in anaerobic digestion were examined. Fe2+supplementation at 10mg/L increased methane yield, but the presence of 8mg/L sulfide led to the precipitation of Fe2+as FeS which limited its bioavailability. The results confirmed that the EDDS could replace common chelating agents with low biodegradability (EDTA and NTA), and improve the bioavailability of Fe2+by forming an Fe-EDDS complex, thereby protecting Fe2+from sulfide precipitation. Experimental findings from sequential extraction using the Community Bureau of Reference (BCR) method, and quantification of free EDDS and Fe-EDDS complex using UHPLC, confirmed that 29.82% of Fe2+was present in bioavailable forms, i.e. soluble and exchangeable, when EDDS was added at 1:1 molar ratio to Fe2+. As a result, the methane production rate increased by 11.17%, and the methane yield increased by 13.25%.
authors.affiliation: Interdisciplinary Graduate School, Nanyang Technological University, Singapore 639798, Singapore; Nanyang Environment & Water Research Institute, Advanced Environmental Biotechnology Centre, Nanyang Technological University, Singapore 637141, Singapore.
authors.forename: Pham Minh
authors.initials: PM
authors.lastname: Thanh
authors.affiliation: Nanyang Environment & Water Research Institute, Advanced Environmental Biotechnology Centre, Nanyang Technological University, Singapore 637141, Singapore.
authors.forename: Balachandran
authors.initials: B
authors.lastname: Ketheesan
authors.affiliation: Nanyang Environment & Water Research Institute, Advanced Environmental Biotechnology Centre, Nanyang Technological University, Singapore 637141, Singapore; School of Civil & Environmental Engineering, College of Engineering, Nanyang Technological University, Singapore 637141, Singapore.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Nanyang Environment & Water Research Institute, Advanced Environmental Biotechnology Centre, Nanyang Technological University, Singapore 637141, Singapore. Electronic address: d.stuckey@imperial.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Stuckey
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D001682:Biological Availability; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D002614:Chelating Agents / Q000737:chemistry / Q000378:metabolism; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005029:Ethylenediamines / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000493:pharmacokinetics*; D008697:Methane / Q000096:biosynthesis*; D013386:Succinates / Q000737:chemistry* / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D002614:Chelating Agents; D005029:Ethylenediamines; D013386:Succinates; D013440:Sulfides; C041447:N,N'-ethylenediamine disuccinic acid; D007501:Iron; D008697:Methane
keywords: Anaerobic digestion; Chelating agent; Metal bioavailability; Metal speciation; Sulfide