Particle size, inoculum-to-substrate ratio and nutrient media effects on biomethane yield from food waste

The impact of attrition ball-mill pretreatment on food waste particle size, soluble chemical oxygen demand (SCOD), biochemical methane potential, and microbial community during anaerobic digestion was investigated based on milling speed and time. The uniformity of particle size improved with increasing milling speed and time. The SCOD of the pretreated samples increased to 4%, 7%, and 17% at the speeds of 150, 225, and 300 rpm, respectively, compared to the control. Milling time did not significantly change the SCOD. The cumulative methane productions of 430, 440, and 490 mL/g-VS were observed at the speeds of 150, 225, and 300 rpm, respectively, while the untreated sample exhibited the cumulative methane production of 390 mL/g-VS. Extended milling time did not improve methane production much. When the milling times of 10, 20, and 30 min were applied with the milling speed fixed at 300 rpm, the methane productions of 490, 510, and 500 mL/g-VS were observed respectively. Ball-mill pretreatment also increased the total volatile fatty acids. During the anaerobic digestion (AD) of ball-mill treated food waste, acetoclastic methanogens predominated, with a relative abundance of 48–49%. Interestingly, hydrogenotrophic methanogens were 1.6 times higher in the pretreated samples than those in the control. These results showed the potential of attrition ball milling as a food waste pretreatment for improving methane production.

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The Effect of Fermentation Process on Physical Properties of Organic Material from Domestic Food Waste

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.860.345 ◽

2020 ◽

Vol 860 ◽

pp. 345-350

Author(s):

Yuli Andriani ◽

Walim Lili ◽

Irfan Zidni ◽

Muhammad Fatah Wiyatna ◽

Risdiana

Keyword(s):

Particle Size ◽

Physical Properties ◽

Food Waste ◽

Organic Material ◽

Fermentation Process ◽

Functional Group ◽

Solid Substrate ◽

Average Particle ◽

Fish Feed ◽

Domestic Food

Organic material produced from domestic food waste can be functionalized as useful product such as fish feed by fermentation process. The fermentation process changed several properties such as nutrition content and particle size. Here, we reported the effect of fermentation process on physical properties of organic material from domestic food waste. In this study, fermented product will be conducted to become fish feed. The fermentation was performed by using commercial probiotic BIOM-S with various levels of probiotic from 0 to 10% using solid substrate fermentation method. The physical properties including nutritional content, particle size, distance between particles, and functional group of fermented organic material from domestic food waste were investigated. After fermentation, it is found that the best level of probiotic use is 8%, which are crude protein increased from 15.58% to 26.16% and crude fiber content decreased from 4.88% to 3.71%. The average particle sizes and distance between particles of fermented domestic food waste fermented by 8% probiotic were 147.723 µm and 1708.802 µm, respectively, while the functional group did not change after fermentation. The present result indicated that fermentation process effected to improve the quality of organic material from domestic food waste.

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Alleviating nutrient imbalance of low carbon-to-nitrogen ratio food waste in anaerobic digestion by controlling the inoculum-to-substrate ratio

Bioresource Technology ◽

10.1016/j.biortech.2021.126342 ◽

2021 ◽

pp. 126342

Author(s):

Yihang Xiao ◽

Feixiang Zan ◽

Weilan Zhang ◽

Tianwei Hao

Keyword(s):

Anaerobic Digestion ◽

Food Waste ◽

Low Carbon ◽

Carbon To Nitrogen Ratio ◽

Nutrient Imbalance ◽

Nitrogen Ratio ◽

Substrate Ratio

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Effect of particle size and sodium ion concentration on anaerobic thermophilic food waste digestion

Water Science & Technology ◽

10.2166/wst.2000.0057 ◽

2000 ◽

Vol 41 (3) ◽

pp. 67-73 ◽

Cited By ~ 50

Author(s):

I.S. Kim ◽

D.H. Kim ◽

S-H. Hyun

Keyword(s):

Particle Size ◽

Food Waste ◽

Substrate Utilization ◽

Sodium Ion ◽

Ion Concentration ◽

Utilization Rate ◽

Average Particle ◽

Organic Loading ◽

Kinetic Coefficients

Serial basic tests were conducted for the determination of fundamental kinetics and for the actual application of kinetic parameters to food waste digestion with precise measurement of methane production. The effects of food particle size and sodium ion concentration on the anaerobic thermophilic food waste digestion process were investigated. Results of serial tests for the determination of fundamental kinetic coefficients showed the value of k (maximum substrate utilization rate coefficient) and KS (half-saturation coefficient) as 0.24 hr−1 and 700 mg/L, respectively, for non-inhibiting organic loading range. The substrate inhibition coefficient (Ki) was 1000 mg/L for inhibiting organic loading range. No inhibition effect was shown until 5g/L of sodium ion concentration was applied to the serum bottle reactor. However, the volume of methane gas was decreased gradually to the concentrations of more than 5 g/L of sodium ion applied. All sizes of food waste particle had the same constants (A:0.45) but the maximum substrate utilization rate constant (kHA) was inversely proportional to particle size. As average particle size increased from 1.02 mm to 2.14 mm, kHA decreased from 0.0033 hr−1 to 0.0015 hr−1. Result reveals that particle size is one of the most important factors in anaerobic food waste digestion.

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