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.

Quantification of parameters influencing methane generation due to biodegradation of municipal solid waste in landfills and laboratory experiments

“…For example, increasing the number of individually operated and controlled landfill cells and consequently reducing W in each cell would lower t max and accelerate k in the cell. Similar to the discussion in Section 3.6, a few studies have demonstrated effective reduction in t max values, which approached those achieved in laboratory experiments (Budka et al 2007;Yazdani et al 2012;Oonk et al 2013). In addition, changing B 0 (%) in landfilled waste appears to have a lower impact than reducing W on reducing t max for landfill cells.…”

“…These include reduction of waste heterogeneity, improvements on the addition, distribution, and migration of moisture in waste, and increased gas collection efficiencies. Some of the potential improvements mentioned previously have been implemented in a few studies and demonstrated very promising increases in k values, which approached those achieved in laboratory experiments (Budka et al 2007;Yazdani et al 2012;Oonk et al 2013). As suggested by Eqn.…”

“…From these, 45 studies were considered sufficiently comprehensive and were selected for further analysis. A database consisting of 49 laboratory experiments (Eleazer et al 1997;Borglin et al 2004;He et al 2005;Francois et al 2006;Dearman and Bentham 2007;Faour et al 2007;Zheng et al 2007;Erses et al 2008;Ivanova et al 2008a;Ivanova et al 2008b;Qu et al 2009;Valencia et al 2009;Gourc et al 2010;Abbassi-Guendouz et al 2012;Cho et al 2012;Huang et al 2012;Mali et al 2012;Bareither et al 2013b;Staub et al 2013;Fei et al 2014aFei et al , 2015 and field monitoring data from 57 landfills was compiled (El-Fadel et al 1996;Morris et al 2003;Bentley et al 2005;Budka et al 2007;Faour et al 2007;Willumsen 2007;Machado et al 2009;Thompson et al 2009;Barlaz et al 2010a;Tolaymat et al 2010;Amini et al 2012;Lamborn 2012;Yazdani et al 2012;Amini et al 2013;Oonk et al 2013;Sormunen et al 2013;Wang et al 2013;Zhao et al 2013). The source and composition of waste, and operating and environmental conditions for / 30 bi...…”

“…5. Unaccounted factors that may influence the values of k for single landfill cells include the frequency of addition of leachate or septage containing high amounts of microorganisms and nutrients for microbial activity (El-Fadel et al 1996;Budka et al 2007;Faour et al 2007;Barlaz et al 2010a;Yazdani et al 2012;Oonk et al 2013;Zhao et al 2013). Because of the low amount and uneven distribution of moisture in relatively dry landfill cells, the values of B and W do not necessarily represent the amount of waste undergoing active biodegradation.…”

Spatial variability of leachate tables, leachate composition and hydraulic conductivity in a landfill stabilized by in situ aeration

“…A novel approach to landfill after-care has seen a focus on the accelerated stabilization of wastes under controlled conditions within in the time frame of current liability using in-situ techniques such as aeration and/or (re-)infiltration of water or leachate. Both techniques aim to decrease a landfill's emission potential by accelerating the decay of reactive organic matter to expedite the attainment of stable conditions in the waste (Kosson et al, 2002;Scharff et al, 2011;van der Sloot et al 2017) and environmentally acceptable residual emissions (Brandstätter et al, 2015a,b, Heyer et al, 2005Oonk et al, 2013;Reinhart et al, 1996Reinhart et al, , 2002Ritzkowkski et al, 2006). These are reached when the water leaving the landfill complies with soil and groundwater quality criteria and can therefore be safely received by soil, ground-and surface waters.…”