title: Enhanced biodegradation at the Landgraaf bioreactor test-cell.
abstract: From 2001 to 2011, a bioreactor demonstration was performed in a 25,000m(3) (8m deep, 3500m(2) surface) test-cell. In this bioreactor, biodegradation was enhanced by premixing and homogenizing of waste, recirculation of leachate and aeration. Anaerobic biodegradation was completed within four years and was followed by two years of aeration. Ultimately a residue was obtained that had lost approximately 95% of its biogas potential. Biodegradation resulted in a significantly reduced leaching potential for dissolved organic carbon (DOC) and specific heavy metals. For other inorganic components, less progress was achieved. Increased flushing would be required for further reduction of the leaching potential. A significant reduction in chemical oxygen demand (COD) and ammonia (NH4(+)) in leachate was not demonstrated during the relative short-term aeration: COD concentrations actually increased slightly and there was no effect on NH4(+). During the project, it became clear that moisture flow through the waste followed preferential flow paths. Therefore, attention was also paid to gain better understanding of leachate flows. From a tracer test, it was concluded that part of the waste contaminants are held in immobile blocks and are to a large extent unaffected by flow occurring in the surrounding preferential flow paths.
authors.affiliation: OonKAY!, Apeldoorn, The Netherlands. Electronic address: hans@oonkay.nl.
authors.forename: Hans
authors.initials: H
authors.lastname: Oonk
authors.forename: André
authors.initials: A
authors.lastname: van Zomeren
authors.forename: Tristan C
authors.initials: TC
authors.lastname: Rees-White
authors.forename: Richard P
authors.initials: RP
authors.lastname: Beaven
authors.forename: Nanne
authors.initials: N
authors.lastname: Hoekstra
authors.forename: Luchien
authors.initials: L
authors.lastname: Luning
authors.forename: Maan
authors.initials: M
authors.lastname: Hannen
authors.forename: Hans
authors.initials: H
authors.lastname: Hermkes
authors.forename: Hans
authors.initials: H
authors.lastname: Woelders
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D062070:Hydrology / Q000379:methods; D019216:Metals, Heavy / Q000378:metabolism; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D000641:Ammonia
keywords: Biodegradation; Hydrology; Landfill; Leachate; Sustainable