Value Proposition of Untapped Wet Wastes: Carboxylic Acid Production through Anaerobic Digestion

Bhatt, Arpit; Ren, Zhiyong Jason; Tao, Ling

doi:10.1016/j.isci.2020.101221

Cited by 66 publications

(48 citation statements)

References 154 publications

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“…A life cycle assessment should be carried out to evaluate and ensure the environmental sustainability of such process 54 . It is worth noting that food waste could be used for the production of value-added chemicals such as carboxylic acids (C 2 –C 6 acids) that may provide a better value proposition 5 , 55 , 56 .…”

Section: Resultsmentioning

confidence: 99%

Techno-economic evaluation of biogas production from food waste via anaerobic digestion

Al-Wahaibi

Osman

Al-Muhtaseb

et al. 2020

Sci Rep

104

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Food waste is a major constituent in municipal solid wastes and its accumulation or disposal of in landfills is problematic, causing environmental issues. Herein, a techno-economic study is carried out on the potential of biogas production from different types of food waste generated locally. The biogas production tests were at two-time sets; 24-h and 21-day intervals and results showed a good correlation between those two-time sets. Thus, we propose to use the 24-h time set to evaluate feedstock fermentation capacity that is intended for longer periods. Our approach could potentially be applied within industry as the 24-h test can give a good indication of the potential substrate gas production as a quick test that saves time, with minimal effort required. Furthermore, polynomial models were used to predict the production of total gas and methane during the fermentation periods, which showed good matching between the theoretical and practical values with a coefficient of determination R2 = 0.99. At day 21, the accumulative gas production value from mixed food waste samples was 1550 mL per 1 g of dry matter. An economic evaluation was conducted and showed that the case study breaks-even at $0.2944 per cubic metre. Any prices above this rate yield a positive net present value (NPV); at $0.39/m3 a discounted payback period of six years and a positive NPV of $3108 were calculated. If waste management fee savings are to be incorporated, the total savings would be higher, increasing annual cash flows and enhancing financial results. This economic evaluation serves as a preliminary guide to assess the economic feasibility based on the fluctuating value of methane when producing biogas from food waste via anaerobic digestion, thus could help biogas project developers investigate similar scale scenarios .

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Section: Resultsmentioning

confidence: 99%

Techno-economic evaluation of biogas production from food waste via anaerobic digestion

Al-Wahaibi

Osman

Al-Muhtaseb

et al. 2020

Sci Rep

104

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“…Life cycle analysis shows the dramatic impact on the carbon footprint if food waste is diverted from landfills to produce VFA-SAF, highlighting the potential to meet jet fuel safety, operability, and environmental goals. waste (2.5 BPGY), animal manure (4.4 BGPY), wastewater sludge (1.9 BPGY), and the abovementioned waste fats, oils, and grease (1.7 BGPY) (14,15). While waste lipid feedstocks may be best suited for HEFA refining, valorization strategies are needed for the remaining wet waste feedstocks.…”

Section: Significancementioning

confidence: 99%

“…California’s Low Carbon Fuel Standard (LCFS) has provided significant economic incentive for producing HEFA from low carbon intensity feedstocks ( 12 ), with petroleum companies continuing to retrofit existing refineries ( 13 ). Although this expansion will significantly increase biofuel production, the US availability of fats, oils, and greases is capped at ∼1.7 BGPY of jet fuel equivalent ( 14 , 15 ). As such, efforts are needed to develop alternative feedstocks and conversion routes for SAF that avoid direct competition with food resources.…”

mentioning

confidence: 99%

“…Wet waste is an underutilized feedstock in the United States, with an energy content equivalent to 10.5 BGPY of jet fuel equivalent (assumed 130.4 MJ/gallon). Wet waste includes food waste (2.5 BPGY), animal manure (4.4 BGPY), wastewater sludge (1.9 BPGY), and the abovementioned waste fats, oils, and grease (1.7 BGPY) ( 14 , 15 ). While waste lipid feedstocks may be best suited for HEFA refining, valorization strategies are needed for the remaining wet waste feedstocks.…”

mentioning

confidence: 99%

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Toward net-zero sustainable aviation fuel with wet waste–derived volatile fatty acids

Huq

Hafenstine

Huo

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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With the increasing demand for net-zero sustainable aviation fuels (SAF), new conversion technologies are needed to process waste feedstocks and meet carbon reduction and cost targets. Wet waste is a low-cost, prevalent feedstock with the energy potential to displace over 20% of US jet fuel consumption; however, its complexity and high moisture typically relegates its use to methane production from anaerobic digestion. To overcome this, methanogenesis can be arrested during fermentation to instead produce C2 to C8 volatile fatty acids (VFA) for catalytic upgrading to SAF. Here, we evaluate the catalytic conversion of food waste–derived VFAs to produce n-paraffin SAF for near-term use as a 10 vol% blend for ASTM “Fast Track” qualification and produce a highly branched, isoparaffin VFA-SAF to increase the renewable blend limit. VFA ketonization models assessed the carbon chain length distributions suitable for each VFA-SAF conversion pathway, and food waste–derived VFA ketonization was demonstrated for >100 h of time on stream at approximately theoretical yield. Fuel property blending models and experimental testing determined normal paraffin VFA-SAF meets 10 vol% fuel specifications for “Fast Track.” Synergistic blending with isoparaffin VFA-SAF increased the blend limit to 70 vol% by addressing flashpoint and viscosity constraints, with sooting 34% lower than fossil jet. Techno-economic analysis evaluated the major catalytic process cost-drivers, determining the minimum fuel selling price as a function of VFA production costs. Life cycle analysis determined that if food waste is diverted from landfills to avoid methane emissions, VFA-SAF could enable up to 165% reduction in greenhouse gas emissions relative to fossil jet.

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“…Lower methane content indicates lower energy yield from the traditional AD process concept, implying energy yield loss on unavoidable CO 2 production. Therefore, research efforts have been driven towards the production of higher value products (such as short chain organic acids and alcohols [118]) that could challenge traditional process of biogas production as a main driver of the AD process.…”

Section: Current Uses and Critical Issues Related To Biogasmentioning

confidence: 99%

Economic Perspectives of Biogas Production via Anaerobic Digestion

2020

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As the demand for utilizing environment-friendly and sustainable energy sources is increasing, the adoption of waste-to-energy technologies has started gaining attention. Producing biogas via anaerobic digestion (AD) is promising and well-established; however, this process in many circumstances is unable to be cost competitive with natural gas. In this research, we provide a technical assessment of current process challenges and compare the cost of biogas production via the AD process from the literature, Aspen Plus process modeling, and CapdetWorks software. We also provide insights on critical factors affecting the AD process and recommendations on optimizing the process. We utilize four types of wet wastes, including wastewater sludge, food waste, swine manure, and fat, oil, and grease, to provide a quantitative assessment of theoretical energy yields of biogas production and its economic potential at different plant scales. Our results show that the cost of biogas production from process and economic models are in line with the literature with a potential to go even lower for small-scale plants with technological advancements. This research illuminates potential cost savings for biogas production using different wastes and guide investors to make informed decisions, while achieving waste management goals.

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Value Proposition of Untapped Wet Wastes: Carboxylic Acid Production through Anaerobic Digestion

Cited by 66 publications

References 154 publications

Techno-economic evaluation of biogas production from food waste via anaerobic digestion

Techno-economic evaluation of biogas production from food waste via anaerobic digestion

Toward net-zero sustainable aviation fuel with wet waste–derived volatile fatty acids

Economic Perspectives of Biogas Production via Anaerobic Digestion

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