Analysing the mechanisms of sludge digestion enhanced by iron

Hao, Xiaodi; Wei, Jing; Loosdrecht, Mark C.M. van; Cao, Da-Qi

doi:10.1016/j.watres.2017.03.048

Cited by 154 publications

(37 citation statements)

References 47 publications

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“…After digestion, the groups treated with 10 g/L ZVI had significantly lower accumulative methane yield than the control, which were 196.6 ± 2.9 mL/g VS and 219.2 ± 7.8 mL/g VS, respectively. This result was inconsistent with the previous studies that ZVI played an active role and increased the methane production in some AD system (Hao et al, 2017;Kong et al, 2018). However, cow manure was not used as a substrate in previous studies, which might be the reason for the difference.…”

Section: Effects Of Zvi On the Ad Of Cow Manurecontrasting

confidence: 85%

Effects of Adding Zero Valent Iron on the Anaerobic Digestion of Cow Manure and Lignocellulose

Men

Zheng

Zhang

et al. 2020

Front. Bioeng. Biotechnol.

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Previous studies showed that adding zero valent iron (ZVI) can increase the methane production and degradation rate of organic waste by improving the performance of anaerobic digester. However, our study firstly found that ZVI (37 µm, 10 g/L) inhibited the anaerobic digestion (AD) of cow manure and lignocellulose. ZVI significantly increased the methanogenic rate of cow manure in the first 6 days, but decreased the accumulative methane yield and volatile fatty acids yield by 10.3 and 12%, respectively. The effect of ZVI on AD of liquid biomass separated from cow manure was positive, but the effect on solid biomass was negative. These results indicated that ZVI enhanced the AD of easily biodegradable organics but inhibited the biodegradation of refractory organics (lignocellulose). By analyzing the varying effects of ZVI in diverse anaerobic systems, it was found that the effects were influenced by the characteristics of substrate and inoculum-substrate ratio. This study suggested that only proper ZVI addition can improve the AD process depending on the feeding materials.

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Section: Effects Of Zvi On the Ad Of Cow Manurecontrasting

confidence: 85%

Effects of Adding Zero Valent Iron on the Anaerobic Digestion of Cow Manure and Lignocellulose

Men

Zheng

Zhang

et al. 2020

Front. Bioeng. Biotechnol.

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“…Zero-valent iron (ZVI) is a novel additive to AD systems and could restore excessive acidification and alleviate low pH through the following pathways: (i) consuming H + by ZVI reducibility, as shown in (Eq. (1)) (Daniels et al, 1987); (ii) stimulating performance of microbial metabolism by iron (Hao et al, 2017); and (iii) causing a low oxidation-reduction potential (E 0 = -440 mV) that is beneficial for acetic acid production and butyric, propionic acid conversion (Xiao et al, 2013).…”

Section: Zero-valent Ironmentioning

confidence: 99%

Improving the stability and efficiency of anaerobic digestion of food waste using additives: A critical review

Liu

et al. 2018

Journal of Cleaner Production

227

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Anaerobic digestion is an effective technology to treat food waste, with methane production as renewable bioenergy. However, there are two key problems in the practical application, i.e., poor system stability and low reactor efficiency. In this paper, additives used in anaerobic digestion of food waste were systematically reviewed in view of system stability and reactor efficiency. Enzymes showed excellent property in food waste pre-hydrolysis stage with almost all macromolecular matters being rapidly resolved. Fungi fermentation process to produce hydrolytic enzymes, can be regarded as a promising and low-cost way to realize rate-limiting step elimination. It can be also concluded that adding neutralizers, buffer chemicals and some other materials is effective to maintain the pH level for practical application. Trace metals in food waste are not enough but needed for methanogens activation in long term and high loading rate operation. In addition, direct interspecies electron transfer could be much helpful for intermediate refractory organic acids degradation and methanogenesis promotion with additives of conductive materials, which is also discussed and should be studied further in anaerobic digestion of food waste. Based on literature review, a new concept is proposed for further study, suggesting that after being well liquefied with enzyme pre-hydrolysis, food waste could be co-digested with landfill leachate in a high-rate anaerobic reactor stably, resulting in a high bioenergy recovery efficiency.

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“…Additionally, hydrogen evolution from iron corrosion could enhance both hydrogentrophic methanogenesis and homoacetogenesis resulting from the increased H 2 flux as intermediary electron carrier [22][23][24], making the microbial consortia more susceptible for DIET. Other researchers observed that the addition of NZVIs leads to an increased conversion of complex organics to volatile fatty acids (VFAs) (i.e., improved hydrolysis and acidogenesis), which, in turn, enhanced the overall methanogenesis of complex substrates [25].…”

Section: Introductionmentioning

confidence: 99%

Impact of Nanoscale Magnetite and Zero Valent Iron on the Batch-Wise Anaerobic Co-Digestion of Food Waste and Waste-Activated Sludge

Kassab

Khater

Odeh

et al. 2020

Water

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As a potential approach for enhanced energy generation from anaerobic digestion, iron-based conductive nanoparticles have been proposed to enhance the methane production yield and rate. In this study, the impact of two different types of iron nanoparticles, namely the nano-zero-valent-iron particles (NZVIs) and magnetite (Fe3O4) nanoparticles (NPs) was investigated, using batch test under mesophilic conditions (35 °C). Magnetite NPs have been applied in doses of 25, 50 and 80 mg/L, corresponding to 13.1, 26.2 and 41.9 mg magnetite NPs/gTS of substrate, respectively. The results reveal that supplementing anaerobic batches with magnetite NPs at a dose of 25 mg/L induces an insignificant effect on hydrolysis and methane production. However, incubation with 50 and 80 mg/L magnetite NPs have instigated comparable positive impact with hydrolysis percentages reaching approximately 95% compared to 63% attained in control batches, in addition to a 50% enhancement in methane production yield. A biodegradability percentage of 94% was achieved with magnetite NP doses of 50 and 80 mg/L, compared to only 62.7% obtained with control incubation. NZVIs were applied in doses of 20, 40 and 60 mg/L, corresponding to 10.8, 21.5 and 32.2 mg NZVIs/gTS of substrate, respectively. The results have shown that supplementing anaerobic batches with NZVIs revealed insignificant impact, most probably due to the agglomeration of NZVI particles and consequently the reduction in available surface area, making the applied doses insufficient for measurable effect.

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Analysing the mechanisms of sludge digestion enhanced by iron

Cited by 154 publications

References 47 publications

Effects of Adding Zero Valent Iron on the Anaerobic Digestion of Cow Manure and Lignocellulose

Effects of Adding Zero Valent Iron on the Anaerobic Digestion of Cow Manure and Lignocellulose

Improving the stability and efficiency of anaerobic digestion of food waste using additives: A critical review

Impact of Nanoscale Magnetite and Zero Valent Iron on the Batch-Wise Anaerobic Co-Digestion of Food Waste and Waste-Activated Sludge

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