title: Anaerobic bioleaching of metals from waste activated sludge.
abstract: Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g(-1) of copper, 487 μg g(-1) of lead, 793 μg g(-1) of zinc, 27 μg g(-1) of nickel and 2.3 μg g(-1) of cadmium. During the anaerobic acidification of 3 gdry weight L(-1) waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.
authors: UNESCO-IHE, Westvest 7, 2611 AX Delft, The Netherlands. Electronic address: roel.meulepas@wetsus.nl.
authors: Roel J W
authors: RJ
authors: Meulepas
authors: UNESCO-IHE, Westvest 7, 2611 AX Delft, The Netherlands; King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000, Saudi Arabia.
authors: Graciela
authors: G
authors: Gonzalez-Gil
authors: UNESCO-IHE, Westvest 7, 2611 AX Delft, The Netherlands.
authors: Fitfety Melese
authors: FM
authors: Teshager
authors: UNESCO-IHE, Westvest 7, 2611 AX Delft, The Netherlands.
authors: Ayoma
authors: A
authors: Witharana
authors: King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000, Saudi Arabia.
authors: Pascal E
authors: PE
authors: Saikaly
authors: UNESCO-IHE, Westvest 7, 2611 AX Delft, The Netherlands.
authors: Piet N L
authors: PN
authors: Lens
mesh_terms: D000383:Agriculture / Q000379:methods*; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D005308:Fertilizers; D008670:Metals / Q000032:analysis* / Q000378:metabolism; D009426:Netherlands; D012722:Sewage; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D005308:Fertilizers; D008670:Metals; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants
keywords: Anaerobic digestion; Bioleaching; Heavy metals; Metal leaching; Waste activated sludge