Full-scale production of VFAs from sewage sludge by anaerobic alkaline fermentation to improve biological nutrients removal in domestic wastewater

Liu, He; Han, Peng; Liu, Hongbo; Zhou, Guangjie; Fu, Bo; Zheng, Zhifeng

doi:10.1016/j.biortech.2018.03.105

Cited by 207 publications

(51 citation statements)

References 34 publications

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“…total amounts depending on the initial inoculum. At this time, the pH reached 3.8 ± 0.1 in WW-F and 4.0 ± 0.2 in CO-F and total gas production was very low (<1 g Cin gas / Lsubstrate d in WW-F; <2 g Cin gas / Lsubstrate d in CO-F), in line with previous studies on hydrolysis of food waste [6,10,20,43,44]. In contrast, in the sludge reactors (CO-S and WW-S), methane content and pH did not drop to similarly low levels when operating at initial parameters of OLR 14.2 kg VS/m 3, d and HRT 5 days.…”

Section: Resultssupporting

confidence: 90%

“…In total, the soluble fraction of TOC, including both ingoing DOC from the substrate and additionally released DOC from the acidic stage, was 41% for both reactors on days 0-50. The outgoing total soluble fraction of TOC was similar to the hydrolysis efficiency (42%) found in a previous study during semi-continuous acidification and hydrolysis of mixed sludge [32,44]. In that study, the hydrolysis efficiency increased with increasing pH and maximum acidification, and hydrolysis efficiency was reached at pH 8.9 and 9.9, respectively.…”

Section: Hydrolysis Efficiencysupporting

confidence: 87%

“…Another limiting factor for optimizing acetate production from the food waste could be the level of available DOC in the substrate. One possible way to increase available DOC would be to pretreat the substrate, shown in a previous study to increase the DOC and VFA production from sourceseparated organic waste [44]. To test the effect of higher DOC on acetate production, additional DOC in the form of glucose was added to the substrate for CO-F during the last 25 days of operation.…”

Section: Acidogenesis and Acetogenesismentioning

confidence: 99%

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Inoculum Source Determines Acetate and Lactate Production during Anaerobic Digestion of Sewage Sludge and Food Waste

et al. 2019

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Acetate production from food waste or sewage sludge was evaluated in four semi-continuous anaerobic digestion processes. To examine the importance of inoculum and substrate for acid production, two different inoculum sources (a wastewater treatment plant (WWTP) and a co-digestion plant treating food and industry waste) and two common substrates (sewage sludge and food waste) were used in process operations. The processes were evaluated with regard to the efficiency of hydrolysis, acidogenesis, acetogenesis, and methanogenesis and the microbial community structure was determined. Feeding sewage sludge led to mixed acid fermentation and low total acid yield, whereas feeding food waste resulted in the production of high acetate and lactate yields. Inoculum from WWTP with sewage sludge substrate resulted in maintained methane production, despite a low hydraulic retention time. For food waste, the process using inoculum from WWTP produced high levels of lactate (30 g/L) and acetate (10 g/L), while the process initiated with inoculum from the co-digestion plant had higher acetate (25 g/L) and lower lactate (15 g/L) levels. The microbial communities developed during acid production consisted of the major genera Lactobacillus (92-100%) with food waste substrate, and Roseburia (44-45%) and Fastidiosipila (16-36%) with sewage sludge substrate. Use of the outgoing material (hydrolysates) in a biogas production system resulted in a non-significant increase in bio-methane production (+5-20%) compared with direct biogas production from food waste and sewage sludge.by slower-growing bacteria that thrive best at neutral pH. These differences in reaction speed and pH optimum allow AD to be divided into two separate production steps, where H 2 and VFA are generated in a primary acid reactor and bio-methane in a secondary reactor. This two-stage approach has been shown to optimize the overall AD process and increase methane yield [3][4][5][6][7][8]. It also allows additional applications, such as the production of bio-hydrogen or of a range of VFA that can be extracted and used as "green" chemical feedstock for further conversion [8,9]. The typical VFA composition in an acidic AD reactor is a mixture dominated by acetate, propionate, butyrate, and valerate [10-13], but it can also be dominated by acetate, butyrate, and H 2 [14], or mainly consist of lactate and/or acetate [15,16]. The amount and type of acid produced depend on both chemical, technical, and microbiological parameters, often interlinked. Parameters shown to be of importance include, for example, reactor configuration, substrate composition and pre-treatment, hydraulic retention time (HRT), temperature, pH, as well as the choice of inoculum and final microbial composition [10,11,[17][18][19][20][21][22].Among the different acids that can be produced in a two-stage set-up, acetate is a highly interesting compound. In addition to being an energy carrier between different stages within AD, it can be used for the production of value-added products such as biopolymers, com...

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Section: Resultssupporting

confidence: 90%

Section: Hydrolysis Efficiencysupporting

confidence: 87%

Section: Acidogenesis and Acetogenesismentioning

confidence: 99%

See 1 more Smart Citation

Inoculum Source Determines Acetate and Lactate Production during Anaerobic Digestion of Sewage Sludge and Food Waste

et al. 2019

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“…Both processes are dependent on the process conditions (e.g., loading rate and pH) and the composition of microbial consortia present (van Aarle et al, ). Previous studies have mainly focused on the VFA fermentation of food waste (FW; Cavinato, Frison, et al, ; Shen et al, ; Yin, Yu, Wang, & Shen, ) and sewage sludge (Jankowska et al, ; Liu et al, ; Peces, Astals, Clarke, & Jensen, ), while a few studies report the use of rural biomasses such as cattle or swine manure (Cavinato, Da Ros, et al, ; Huang et al, ). Food waste is a major waste fraction in urban areas and it has potential for the production of various energy carriers in a centralized urban context, while manure and slurry are produced in vast quantities in areas of intense animal production and have potential mostly in decentralized farm systems.…”

Section: Introductionmentioning

confidence: 99%

“…The production of VFAs through mixed consortia fermentation can utilize more complex substrates in nonsterile conditions (Jankowska, Chwiałkowska, Stodolny, & Oleskowicz-Popiel, 2015;Jankowska, Duber, Chwialkowska, Stodolny, & Oleskowicz-Popiel, 2018). However, to date, the VFA production process through anaerobic digestion with mixed consortia is still in the upscaling phase (Esteban-Gutiérrez, Garcia-Aguirre, Irizar, & Aymerich, 2018) and the full-scale production has been tested with very narrow spectrum of utilizable biomasses, for example, with sewage sludge (Liu et al, 2018). Therefore, there is currently a need to evaluate the potential of various biomasses as substrates for mixed consortia VFA fermentation to boost the production of green chemicals in the circular economy.…”

mentioning

confidence: 99%

Volatile fatty acids (VFAs) and methane from food waste and cow slurry: Comparison of biogas and VFA fermentation processes

et al. 2018

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The potential of various biomasses for the production of green chemicals is currently one of the key topics in the field of the circular economy. Volatile fatty acids (VFAs) are intermediates in the methane formation pathway of anaerobic digestion and they can be produced in similar reactors as biogas to increase the productivity of a digestion plant, as VFAs have more varying end uses compared to biogas and methane. In this study, the aim was to assess the biogas and VFA production of food waste (FW) and cow slurry (CS) using the anaerobic biogas plant inoculum treating the corresponding substrates. The biogas and VFA production of both biomasses were studied in identical batch scale laboratory conditions while the process performance was assessed with chemical and microbial analyses. As a result, FW and CS were shown to have different chemical performances and microbial dynamics in both VFA and biogas processes. FW as a substrate showed higher yields in both processes (435 ml CH4/g VSfed and 434 mg VFA/g VSfed) due to its characteristics (pH, organic composition, microbial communities), and thus, the vast volume of CS makes it also a relevant substrate for VFA and biogas production. In this study, VFA profiles were highly dependent on the substrate and inoculum characteristics, while orders Clostridiales and Lactobacillales were connected with high VFA and butyric acid production with FW as a substrate. In conclusion, anaerobic digestion supports the implementation of the waste management hierarchy as it enables the production of renewable green chemicals from both urban and rural waste materials.

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Impact of pH, temperature, and hydraulic residence time on the acidogenic fermentation of fruit and vegetable waste and microbial community analysis

Liu

Wang

et al. 2022

J of Chemical Tech & Biotech

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BACKGROUND: The carboxylic acids produced through acidogenic fermentation of fruit and vegetable waste present wide application and high added value. By performing batch experiments, the influence of pH and temperature on the acidogenic fermentation performance was investigated, and the effects of hydraulic retention time (HRT) on performance and microbial community in semi-continuous fermentation were also studied.RESULTS: A maximum product yield of 0.66 ± 0.01 g g −1 VS fed (volatile solids of feed substrate) was found at mesophilic temperature and pH 9.0; acetic acid, propionic acid, and butyric acid comprised 59%, 20%, and 21% of the product, respectively. During semi-continuous fermentation, a maximum product yield of 0.69 ± 0.03 g g −1 VS fed was found at pH 9.0 and an HRT of 5 days. Lactic acid and acetic acid were regarded as the main products, with respective percentages of 85% and 12%. Reducing the HRT to 3 days increased the daily production from 11.33 ± 0.46 to 15.89 ± 0.67 g d −1 . Microbial community analysis revealed that Lactobacillus was predominant in the semi-continuous alkaline fermentation system. CONCLUSION: Alkaline fermentation was more favorable for obtaining higher product yield both in batch and semi-continuous fermentation. Within semi-continuous alkaline fermentation, the maximum yield was observed at an HRT of 5 days, but a higher daily production was found at an HRT of 3 days. Additionally, reducing the HRT did not change the dominant bacteria but could change the composition of the products. This work provides a theoretical basis and guidance for enhancing product yield and optimizing formation of product.

show abstract

Full-scale production of VFAs from sewage sludge by anaerobic alkaline fermentation to improve biological nutrients removal in domestic wastewater

Cited by 207 publications

References 34 publications

Inoculum Source Determines Acetate and Lactate Production during Anaerobic Digestion of Sewage Sludge and Food Waste

Inoculum Source Determines Acetate and Lactate Production during Anaerobic Digestion of Sewage Sludge and Food Waste

Volatile fatty acids (VFAs) and methane from food waste and cow slurry: Comparison of biogas and VFA fermentation processes

Impact of pH, temperature, and hydraulic residence time on the acidogenic fermentation of fruit and vegetable waste and microbial community analysis

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