Methane Potential of Food Waste and Anaerobic Toxicity of Leachate Produced During Food Waste Decomposition

Abstract

The objective of this study was to characterize the anaerobic biodegradation of food waste, including its methane potential and the anaerobic toxicity of leachate associated with food waste decomposition. Biodegradation experiments were conducted in 2.2litre reactors and were seeded with well-decomposed refuse. Despite pH neutralization, reactors seeded with 30% old refuse failed to undergo methanogenesis. Food waste in a second set of reactors, containing 70% seed, produced 300.7 ml CH 4 dry g -1 . Leachate toxicity was evaluated by a modified anaerobic toxicity assay (ATA). The results of ATAs were typically consistent with the methane production behavior of the reactors. However, the toxicity observed in the ATA test could not be simulated with synthetic leachate containing high concentrations of carboxylic acids and sodium. Tests with 20, 5, 15 and 12 g 1 ' of acetate, propionate, butyrate and sodium, respectively, suggested that high concentrations of butyric acid and sodium inhibited the onset of methane production but that refuse micro-organisms could acchmatize to these concentrations within 5-10 days. The refuse ecosystem was shown to tolerate higher concentrations of undissociated carboxylic acids than previously reported for anaerobic digesters. © 1997 ISWA

Biostabilization of municipal solid waste

“…3), which were characterized by the acidification and the production of CO 2 alone because of the toxic effect of low pH and the presence of non-dissociated toxic form volatile fatty acid (Farquahar and Rovers, 1997;Eidloth, 1997;Wang et al, 1997). On the other hand, samples 21A and 21B had biogas production behavior comparable to a landfill during phase III (Fig.…”

“…Therefore, the inhibition was caused by an imbalance in the growth rates of fast-growing acid genetic bacteria and acetoclastic methanegens that occur during first stage of decomposition (Nopharatana et al, 1998). The addition of seed guaranteed the presence of a more balanced population, eliminating toxic effect (Wang et al, 1997).…”

“…Wang et al (1997) pointed out that food wastes (FW) did not produce biogas even when they were mixed with seed (S) in the ratio of 3:1 on a dry matter basis (FW:S) and were pH-buffered. On the other hand, when the ratio was 1:3.55 (FW:S), methane was produced at the rate of 300 L kg TS À1 .…”

Assessment of the effectiveness of an industrial unit of mechanical–biological treatment of municipal solid waste

“…Description of the test method for the determination of BP and BMP was provided by several authors [25][26][27][28][29]. Preliminary experiments on similar waste showed that 90 days of incubation at 35 • C, after the lag period, was sufficient to insure the total gas production expression.…”

Methane emissions as energy reservoir: Context, scope, causes and mitigation strategies

“…The Barlaz laboratory, working with mesocosm landfill analogs for several decades, has shown ground, moist organic material will degrade under landfill conditions [199]. Food was shown to degrade rapidly and readily although CH4 inhibition occurred with a subset of samples, apparently due to high VOA [200]; grass samples nearly all degraded, and over half of corrugated cardboard and office paper was degraded to CH4, so that about 50% of all degradable MSW was gasified [199]. But not all constituents degrade even under these optimal anaerobic conditions [201].…”