Instability mechanisms and early warning indicators for mesophilic anaerobic digestion of vegetable waste

Dong, Li; Lin, Chen; Liu, Xiaofeng; Mei, Zili; Ren, Haiwei; Cao, Qin; Yan, Zhiying

doi:10.1016/j.biortech.2017.07.098

Cited by 86 publications

(43 citation statements)

References 42 publications

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“…Fruits contain sugar and are rapidly converted into VFAs by acid-fermenting bacteria. However, this can cause the accumulation of VFAs, which can cause a rapid decrease in the pH inside the reactor [31]. In particular, methanogens have a slower growth rate and are not as adaptable to a rapid decrease in pH compared to acid-fermenting bacteria; therefore, a sudden decrease in pH can reduce the efficiency of anaerobic digestion [32].…”

Section: Results Of the Bmp Testmentioning

confidence: 99%

Evaluation of Anaerobic Co-Digestion to Enhance the Efficiency of Livestock Manure Anaerobic Digestion

2019

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In this paper, the anaerobic co-digestion of three different organic wastes, including livestock manure, slaughterhouse waste, and agricultural by-products (ABs), was carried out to enhance the efficiency of mono-digestion of livestock manure. The characteristics of co-digestion were evaluated at different mixing ratios. The experiment was performed using the Batch test and was divided into two parts. The first experimental section (EXP. 1) was designed to evaluate the seasonal characteristics of ABs, which are the different ratios of fruits and vegetables, where the mixing ratio of spring (fruits:vegetables = 3:7) showed the highest biogas yield (0.24 m3/kg volatile solids). The second experiment (EXP. 2) was conducted by using ABs in the ratio that gave the highest biogas yield in EXP. 1 in combinations of three wastes livestock manure, slaughterhouse waste, and ABs. The highest CH4 yield was 0.84 m3/kg volatile solids (VS), which was obtained with a mixing ratio that had even amounts of the three feedstocks. In addition, the results of the second biochemical methane potential test, which assessed the digestive efficiency according to the mixing ratio of the three types of organic waste, showed that the CH4 production rate of the merged digestion was approximately 1.03–1.29 times higher than that of the mono-digestion of livestock manure. The results of our experiment were verified using the modified Gompertz model, the results of which were relatively similar to the experimental results.

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Section: Results Of the Bmp Testmentioning

confidence: 99%

Evaluation of Anaerobic Co-Digestion to Enhance the Efficiency of Livestock Manure Anaerobic Digestion

2019

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“…The performances of anaerobic treatments, besides the reactors type and the operating conditions, are largely affected by the feedstock properties [26]. The applicability of digestion processes for the treatment of many types of organic residues has been investigated in the last years [27][28][29][30][31]. However, few studies have been focused on the treatment of compost leachate by means of anaerobic reactors.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, each group of microorganisms is characterized by different optimal pH ranges. Methanogenic bacteria can operate within a quite restricted pH range, with the optimal values being 6.5-8.0 [27]. Fermentative bacteria can work within a wider pH range of 4-8.5 [27].…”

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confidence: 99%

Biogas Generation through Anaerobic Digestion of Compost Leachate in Semi-Continuous Completely Stirred Tank Reactors

et al. 2019

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The composting process of organic fraction of municipal solid waste, besides to the residual compost, generates a wastewater that is characterized by a high organic load. The application of anaerobic processes represents an advantageous solution for the treatment and valorization of this type of wastewater. Nevertheless, few works have been focused on the anaerobic digestion of compost leachate. To overcome this dearth, in the present paper an extensive experimental investigation was carried out to develop and analyse the anaerobic treatment of young leachate in completely stirred tank reactors (CSTR). Initially, it was defined a suitable leachate pretreatment to correct its acidic characteristics that is potentially able to inhibit methanogenic biomass activity. The pretreated leachate was fed to the digester over the start-up phase that was completed in about 40 days. During the operational period, the organic load rate (OLR) changed between 4.25 kgCOD/m3d and 38.5 kgCOD/m3d. The chemical oxygen demand (COD) abatement was higher than 90% for OLR values up to 14.5 kgCOD/m3d and around to 80% for applied loads equal to 24.5 kgCOD/m3d. At this OLR, it was reached the maximum daily biogas production of about 9.3 Lbiogas/(Lreactord). The CH4 fraction was between 70%–78% and the methane production yield in the range 0.34–0.38 LCH4/gCODremoved. The deterioration of biogas production started for OLR values that were over the threshold of 24.5 kgCOD/m3d when a volatile fatty acids (VFA) accumulation occurred and the pH dropped below 6.5. The maximum ratio between VFA and alkalinity (ALK) tolerable in the CSTR was identified to be 0.5 gCH3COOH/gCaCO3. Through an economic analysis, it was proven that the digestion of compost leachate could ensure significant economic profits. Furthermore, the produced digestate had characteristics that were compatible for agricultural applications.

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“…Anaerobically digested sludge was used as inoculum and taken from an existing full-scale anaerobic digester treating palm oil mill effluent (POME) [23,24]. The substrate slurry and inoculum were placed in a cold room at 4°C when it is not in use [25].…”

Section: Samples Of Ripe Banana Peelmentioning

confidence: 99%

Energy Recovery from Anaerobic Digestion of Banana Peels

Shaharoshaha¹,

Sulaiman²,

Seswoya³

2019

IJRTE

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Bananas are tropical fruits mostly eaten in Malaysia. The banana peels are high in organic, and putrescible caused the odour and leachate problem where it has been a dump. In practice, banana peels considered as a waste product that has been combined with municipal solid waste and dumped into the landfills. However, banana peels are bountiful in organic matter and high with moisture content. Thus, it could be a convincing substrate for biogas production through anaerobic digestion so that the major concerns of environmental protection is achieved aside from producing energy in a sustainable way. Therefore, this study was initiated to estimate the ultimate methane yield from the unripe banana peel (UBP) and ripe banana peel (RBP). Besides that, the assessment on the kinetics of the methane production from UBP and RBP is conducted using Modified Gompertz and first-order kinetic modelling. In this study, the anaerobic digestibility of banana peels measured in a batch reactor for 25 days each fed by UBP and RBP. The batch reactors operated at an inoculum to substrate ratio (I/S) of 1.0 and at a mesophilic temperature (37°C). The ultimate methane yields from UBP and RBP digestion were 847.57mLCH4 /gVS and 1405.31mLCH4 /gVS, respectively. The higher bioavailability (in term of COD, and solid) in RBP resulted in the higher methane production rate. Two first-order and modified Gompertz kinetic models were compared for the prediction of organic degradation, and the results indicated that the first-order kinetic model of the RBP fitted the experiment best. It concluded that ripe banana peels are the most preferable feedstock for the anaerobic digestion.

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Instability mechanisms and early warning indicators for mesophilic anaerobic digestion of vegetable waste

Cited by 86 publications

References 42 publications

Evaluation of Anaerobic Co-Digestion to Enhance the Efficiency of Livestock Manure Anaerobic Digestion

Evaluation of Anaerobic Co-Digestion to Enhance the Efficiency of Livestock Manure Anaerobic Digestion

Biogas Generation through Anaerobic Digestion of Compost Leachate in Semi-Continuous Completely Stirred Tank Reactors

Energy Recovery from Anaerobic Digestion of Banana Peels

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