Effect of various leachate recirculation strategies on batch anaerobic digestion of solid substrates

Kusch, Sigrid; Oechsner, Hans; Jungbluth, Thomas

doi:10.1504/ijewm.2012.044161

Cited by 39 publications

(22 citation statements)

References 73 publications

(98 reference statements)

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“…It was found that leaching is favorable for the anaerobic decomposition of food waste. However, depending on the frequency of recirculation, it can increase acidogenesis, which may result in the inhibition of methanogenesis (Kusch et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Marchioro

Steinmetz

Amaral

et al. 2018

Front. Sustain. Food Syst.

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This study evaluated the effect of the substrate:inoculum ratio and digestate recirculation conditions on the biogas and methane yield, free ammonia concentration and solid phase agronomic quality (after treatment) of poultry litter solid state anaerobic digestion (SSAD). Experimental tests were conducted using a central composite design (2²), with four trials at the factorial points and three at the central points, using poultry litter as substrate that was collected after 12 cycles of broiler production [TS 76% (w.w −1 )]. Three laboratory-scale reactors containing 3 kg of poultry litter each were operated at mesophilic conditions (37 • C) and seven experimental runs were performed at retention time of 30 days each. There were three substrate:inoculum ratios (1:1; 1:1.66, and 1:3) and three daily recirculation intervals (2, 3, and 4 times per day), and each recirculation event lasted 15 min. The highest biogas and methane yields were183 L Nbiogas .kg VSadd , respectively, and they were obtained at the substrate:inoculum ratio of 1:3 with a digestate recirculation frequency of four times a day. Digestate recirculation was the variable that influenced the concentration of free ammonia; the most frequently recirculated tests had lower concentrations (below 60 mgNH 3 .L −1 ). After the SSAD process, we identified a transfer of nutrients (N, P, K) from the solid phase to the liquid phase. The nutrient concentrations in the solid phase (N out = 11 g.kg −1 , K out = 5 g.kg −1 , and P out = 7 g.kg −1 ) indicated that the digested poultry litter still has potential for use in fertilization. In this study, it was estimated that 90 m 3 biogas .tons −1 poultrylitter was generated using SSAD. Whereas 100 tons of poultry litter are produced after 12 production cycles, the biogas generation capacity reaches 9,000 m 3 /year. In this scenario, farmers can use biogas from poultry litter SSAD as an additional source of energy.

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Section: Introductionmentioning

confidence: 99%

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Marchioro

Steinmetz

Amaral

et al. 2018

Front. Sustain. Food Syst.

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“…Optimal conditions are difficult to be determined and to be fulfilled at farm-scale, which increases the risk of incomplete degradation in this simple fermenter type with no substrate mixing. It has been demonstrated that during process initiation discontinuous leachate recirculation is more favourable than continuous watering (Kusch et al, 2012;Martin, 1999;Vavilin et al, 2002Vavilin et al, , 2003Veeken and Hamelers, 2000), which is assumed to be the result of encouraging methanogenic areas to expand throughout the whole digester, while continuous watering bears the risk to spread acidification. In addition, it was demonstrated that for the process type discussed here there is no beneficial effect of continuous water circulation compared to discontinuous watering throughout the whole digestion process (Kusch et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Dry Digestion of Organic Residues

Kusch¹,

Schäfer²,

Kranert³

2011

Integrated Waste Management - Volume I

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“…As the substrate in Mix II (Dung) was completely mixed with the inoculum, acidification presumably took place throughout the digester and thus being irreversible. This underlines the advantage of bottom inoculation or layered inoculation, where acidification can be locally limited, so that active zones are maintained and complete process failure can be prevented [14,23].…”

Section: Performance Of the Second Ssad Runmentioning

confidence: 99%

“…Moreover, the low water content in SSAD can limit mass transfer of intermediate compounds in the digester, which can significantly slow down the digestion process [13]. Additionally, the high risk of irreversible acidification requires a high inoculum to substrate (I/S) ratio [14]. In order to accelerate mass transfer and reduce the risk of acidification SSAD is often operated in two-stage digesters and/or with leachate recirculation [15,16].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Novel Inoculation Strategies for Solid State Anaerobic Digestion of Yam Peelings in Low-Tech Digesters

Heiske¹,

Jurgutis

Kádár³

2015

Energies

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Abstract:The operation of household scale anaerobic digesters is typically based on diluted animal dung, requiring stabled livestock and adequate water availability. This excludes many rural households in low-income countries from the benefits of a domestic biogas digester. Solid state anaerobic digestion (SSAD) can be operated with low process water demands, but the technology involves operational challenges, as e.g., risk of process acidification or low degradation rates. This study aimed at developing simple methods to perform SSAD of yam peelings in low-tech applications by testing different inoculation strategies and evaluating the necessity of dung addition as a supportive biomass. In initial lab scale trials 143 ± 4 mL CH4/g VS (volatile solids) were obtained from a mixture of yam peelings and dung digested in a multi-layer-inoculated batch reactor. In a consecutive incubation cycle in which adapted inoculum was applied, bottom inoculated digesters loaded without dung reached a yield of 140 ± 16 mL CH4/g VS. This indicates that SSAD of yam peelings is possible with simple inoculation methods and dung addition is unnecessary after microbial adaptation. A comparison with a conventional fixed dome digester indicated that SSAD can reduce process water demand and the digester volume necessary to supply a given biogas demand.

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Effect of various leachate recirculation strategies on batch anaerobic digestion of solid substrates

Cited by 39 publications

References 73 publications

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Dry Digestion of Organic Residues

Evaluation of Novel Inoculation Strategies for Solid State Anaerobic Digestion of Yam Peelings in Low-Tech Digesters

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