Effects of substrate concentration on methane potential and degradation kinetics in batch anaerobic digestion

Wang, Bing; Strömberg, Sten; Li, Chao; Nges, Ivo Achu; Nistor, Mihaela; Deng, Liangwei; Liu, Jing

doi:10.1016/j.biortech.2015.07.034

Cited by 52 publications

(27 citation statements)

References 27 publications

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“…Since wet mass of inoculum in diluted samples differed from the blanks, calculation of background methane production was based on VS of inoculum added to each bottle. Figure 3 shows that with increasing dilution, the BMP is lowered, which is in agreement with findings of previous studies (Wang et al, 2015;Reilly et al, 2016). For the most extreme case of 1:2 dilution (VS content in the mixture reduced from 19.2 to 6.4 g VS /L), the slope during the plateau phase became negative, which indicates that the methane production from bottles with substrate but diluted with water was even lower than that of the undiluted blanks.…”

Section: Impact Of Inoculum Dilution On Smp Curvessupporting

confidence: 90%

“…Hence, a dilution of the substrate is normally not needed, as long as the inoculum already provides enough moisture. Recent studies have proven that dilution of the inoculum below 10 g VS /L will even cause an underestimation of methane potential from BMP test and should thus be avoided (Wang et al, 2015;Reilly et al, 2016). Owing to incorrect interpretation of the recommendation in the guidelines (Angelidaki et al, 2009;Holliger et al, 2016), which refers to the substrate TS concentration and not to the inoculum or the mixture, an unnecessary dilution with water might be another source of error.…”

Section: Impact Of Inoculum Dilution On Smp Curvesmentioning

confidence: 99%

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Identification of Critical Problems in Biochemical Methane Potential (BMP) Tests From Methane Production Curves

Koch

Hafner

Weinrich

et al. 2019

Front. Environ. Sci.

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Biochemical methane potential (BMP) tests are routinely conducted in academia and industry to determine the methane potential of a given substrate. Although many guidelines have been proposed to standardize BMP tests, results published in the peer-reviewed literature show that critical flaws in experimental design or execution are still common. Therefore, a powerful but simple method for evaluating the quality of BMP measurements is proposed in this work: the specific methane production (SMP) curve from any BMP trial should have a similar shape for most substrates, and significant deviation from this typical response is usually associated with a lack of reliability in resulting BMP estimates. In this study, some common experimental mistakes were reproduced to demonstrate this concept and establish relationships between flaws in experiments, SMP curves, and BMP values. The studied flaws were inoculum storage (2 weeks and at different temperatures), inoculum dilution with water (no dilution to 1:2 dilution), and inoculum-to-substrate ratio (from 2.00 to 0.05). Common kinetic models were used to better assess SMP curves. All flaws exhibited an impact on the SMP curves, but excessive dilution and extremely low inoculum-to-substrate ratio had the largest impacts on both SMP curves and BMP. In the most extreme case (ISR of 0.05), there was a clear lag phase of more than 10 days, and the resulting BMP was 15% lower than for the reference case. Together these results demonstrate the utility of the proposed method. The ultimate goal of this research is to help less experienced researchers identify and address problems in their experimental procedure, ultimately contributing to more accurate BMP measurements. The general approach is both simple and useful, and should always be part of a quality check for BMP tests.

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Section: Impact Of Inoculum Dilution On Smp Curvessupporting

confidence: 90%

Section: Impact Of Inoculum Dilution On Smp Curvesmentioning

confidence: 99%

Identification of Critical Problems in Biochemical Methane Potential (BMP) Tests From Methane Production Curves

Koch

Hafner

Weinrich

et al. 2019

Front. Environ. Sci.

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“…The destabilizations of the microbial community can lead to the limited substrate and product transport. According to Zhang et al [11,48], damage cells and reduced activities of microbial communities may have been stressed. Biomass floatation and biomass washout were observed with R1 effluent, with TCOD increased from 22,250 mg L −1 before the oil addition to 79,400 mg L −1 (71.66%), while that of R2 remained relatively stable at 37,600 mg L −1 from 35,500 mg L −1 before, oil was added as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Some researchers have suggested that ammonia can also buffer or neutralised the VFAs during the AD process, thereby stabilising the system and avoiding AD failure [1,6,48,51]. As shown in Fig.…”

Section: + -N Ts Reduction Vs Conversion Efficiency and Phmentioning

confidence: 99%

Effect of Oil Content on Biogas Production, Process Performance and Stability of Food Waste Anaerobic Digestion

Awe

et al. 2017

Waste Biomass Valor

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The primary cause of anaerobic digester failure includes accumulation of inhibitory substances and intermediate products such as volatile fatty acids (VFAs), free ammonia (NH 3 + ), and ammonium (NH 4 + ). They (except VFAs) are however required as essential nutrients for bacteria growth. The current study specifically investigated the effect of oil content on the biogas production and the stability of anaerobic digestion of food waste. Two lab scale reactors were designed with different organic loading rates and feeding adjustment of used oil addition to testing the effects of lipids on biodegradation and biogas production. The results indicate that, at 2.0 g VS L −1 d −1 , the addition of oil (5% v/v), caused the reactor failure, whereas, at 4.0 g VS L −1 d −1 , the reactor remained stable for 10 days before the accumulation of VFAs, which resulted in low pH, and thus reduced the biogas and methane production. The addition of NaOH to reactivate the reactors can only improve pH, alkalinity and negatively increased viscosity, but there was no significant effect on biogas production and VFAs concentration. An effective solution to reactivate the reactors was achieved by recirculating 50% of both reactor's effluent back to the reactors. This resulted in biogas recovery and stable process performance of the reactors. Surprisingly, NH 4 + -N remained stable (1400 mg L −1 ) throughout the period, far less than the critical concentration of 3000 mg L −1 . On the contrary, the low NH 4 + -N couldn't contribute to buffering the reactor's high VFA concentration during the unstable period, thereby raising new questions on its roles in anaerobic digestion process.

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“…Lipids provide the highest biogas yield, but require longer retention time owing to their slow kinetic of biodegradability; whereas, carbohydrates and proteins show fast conversion rates but low biogas yield. Thus, in the co-digestion process protein-rich wastes can provide the buffering capacity and a wide range of nutrients, and wastes with high carbon content can balance the C/N ratio for all substrates characterised by a low C/N ratio, thereby decreasing the risk of ammonia inhibition [9]. To overcome this limitation, researchers have concentrated on co-digestion of FW with SS to augment nutrient imbalance [1,2,4,12,31,34,41,43,44].…”

Section: Substrates For Co-digestionmentioning

confidence: 99%

Anaerobic co-digestion of food waste and FOG with sewage sludge – realising its potential in Ireland

Awe

Nzihou

Minh

et al. 2017

International Journal of Environmental Studies

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The severe environmental pollution in many countries is caused by indiscriminate discharge of large quantities of food waste (FW), fat oil and grease (FOG) and sewage sludge (SS) to the environment. There are many possible treatment routes, but anaerobic digestion (AD) is now well accepted for treating several kinds of organic wastes. But AD of FW alone presents some operational challenges because of substrates and variability. Anaerobic co-digestion of two or more substrates is better than single substrate digestion. This can use a plant's unused capacity, in line with the trend to renewable energy. Co-digestion technology, although well established in many European countries, is still in its infancy in Ireland. There are problems with different regulatory arrangements. They should be resolved. The paper reviews anaerobic co-digestion technology is reviewed, with special focus on possible application in Ireland.

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Effects of substrate concentration on methane potential and degradation kinetics in batch anaerobic digestion

Cited by 52 publications

References 27 publications

Identification of Critical Problems in Biochemical Methane Potential (BMP) Tests From Methane Production Curves

Identification of Critical Problems in Biochemical Methane Potential (BMP) Tests From Methane Production Curves

Effect of Oil Content on Biogas Production, Process Performance and Stability of Food Waste Anaerobic Digestion

Anaerobic co-digestion of food waste and FOG with sewage sludge – realising its potential in Ireland

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