Free nitrous acid pre-treatment enhances anaerobic digestion of waste activated sludge and rheological properties of digested sludge: A pilot-scale study

Meng, Jia; Duan, Haoran; Li, Huijuan; Watts, S. R.; Liu, Peng; Shrestha, Sohan; Zheng, Min; Yu, Wenbo; Chen, Zhongwei; Song, Yarong; Dwyer, Jason; Hu, Shihu; Yuan, Zhiguo

doi:10.1016/j.watres.2020.115515

Cited by 37 publications

(16 citation statements)

References 42 publications

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“…In a progressive manner, the effectiveness of FNA pre-treatment on AD performance was recently demonstrated at pilot-scale (Meng et al 2019). Two pilot-scale AD reactors were continuously operated for one year at a full-scale WWTP, one receiving full-scale WAS (control) and another receiving WAS pre-treated for 24 h at an FNA concentration of 4.9-6.1 mgN/L (nitrite = 250 mgN/L, pH = 5.0, T = 22-30 °C).…”

Section: Enhancing Sludge Reduction and Energy Recovery In Sludge Manmentioning

confidence: 99%

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Improving wastewater management using free nitrous acid (FNA)

et al. 2020

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Section: Enhancing Sludge Reduction and Energy Recovery In Sludge Manmentioning

confidence: 99%

“…Apart from the use of FNA in sewer systems, other FNA studies were all conducted in laboratories (with the exception of Meng et al (2019) at pilot-scale). Some constraints of the lab-scale studies should be realised.…”

Section: Constraints Of Lab-scale Studies Call For Pilot-and Full-scamentioning

confidence: 99%

Improving wastewater management using free nitrous acid (FNA)

et al. 2020

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“…Pretreatment of WAS at an FNA concentration of 6.09 mg N/L for 24 h has been found to increase biogas production at pilot scale by 30–35%, with a corresponding increase in volatile solids (VS) destruction . There is strong evidence that the pretreatment of WAS with FNA concentrations significantly enhanced WAS solubilization compared to that without FNA pretreatment . It was also found that FNA pretreatment enabled reduction of the hydraulic retention time (HRT) of the anaerobic digester from 15 days to 7.5 days, while still enhancing the performance of the digester in terms of biogas production and VS destruction .…”

Section: Introductionmentioning

confidence: 99%

“…It was found that FNA pretreatment substantially enhanced the shear viscosity and viscosity of WAS, likely due to the enhanced VS destruction and disintegration of the digested sludge . In both applications, it was hypothesized that the FNA-based treatment caused the lysis of bacterial cells in biofilms and in activated sludge, resulting in the loss of bacterial integrity and the release of intracellular materials. − …”

Section: Introductionmentioning

confidence: 99%

Structural Changes in Cell-Wall and Cell-Membrane Organic Materials Following Exposure to Free Nitrous Acid

Chislett

Guo

Bond

et al. 2020

Environ. Sci. Technol.

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Previous studies demonstrate that free nitrous acid (FNA, i.e., HNO2) is biocidal for a range of microorganisms. The biocidal mechanisms of FNA are largely unknown. In this work, it is hypothesized that FNA will break bonds in molecules found in the cell envelope, thus causing cell lysis. Selected molecules representing components found in the cell envelope were treated with FNA at 6.09 mg N/L (NO2 – = 250 mg N/L, pH 5.0) for 24 h (conditions typically used in applications) to evaluate the hypothesized chemical interactions. Molecular changes were observed using analytical techniques including proton (1H) nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization mass spectrometry (ESI-MS). It was found that FNA broke down a range of cell envelope molecules. The spectral data demonstrated that the FNA reactions proceeded via two general pathways. One consisted of electrophilic substitution, whereby the nitrosonium ion (NO+) was the reactive electrophile. The other was via oxidative reactions involving nitrogen radicals (e.g., •NO2 and •NO) formed from the decomposition of FNA. We further revealed that it was HNO2 that caused the breakdown, rather than the exclusive action of the acid (H+) or nitrite (NO2 –) counterparts. The fragmentation of these representative cell envelope molecules provides insight into the biocidal effects of FNA on microorganisms.

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“…Pretreatment of tobacco stalks by Zhang et al [33] with HCl and oxalic acid (H 2 C 2 O 4 ) at 1%, 3%, 5% and 7% (w/w) concentration each revealed an increase in cumulative methane generation by 19.2% and 21% after pretreatment with 5% HCl and 7% H 2 C 2 O 4 , respectively. Pretreatment of thickened waste activated sludge with free nitrous acid (4.9-6.1 mgN/l) for 24 h enhanced methane production in a pilot-scale reactor by 37% as compared to untreated WAS [34]. Improvement of 20.6% in methane potential was observed by Passos et al [35] during anaerobic digestion of dairy cow manure pretreated with 2% HCl at 37 °C.…”

Section: Discussionmentioning

confidence: 87%

Enhancement of biogas production from organic fraction of municipal solid waste using acid pretreatment

Dasgupta

Chandel

2020

SN Appl. Sci.

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Anaerobic digestion of organic fraction of municipal solid waste (OFMSW) is a potential and economic technique for harnessing bioenergy from Indian municipal solid waste. Pretreatment before anaerobic digestion has been known to improve biodegradability of substrate and enhance biogas production. In this study, the effectiveness of acid pretreatment in enhancing the hydrolysis of complex organic matter and ensuing biogas generation from OFMSW was studied using one strong and one weak acid. Acid pretreatment (pH 6-pH 1) of OFMSW was carried out using hydrochloric acid (HCl) and acetic acid (CH 3 COOH) for 24 h before batch anaerobic digestion assays with cow dung as inoculum. Increase in biogas yield ranged between 13.2 and 28.9% as compared to untreated OFMSW after pretreatment with HCl, whereas the same varied between 8.2 and 16% in case of CH 3 COOH pretreatment. The highest biogas yield (389.4 ml/gVS) with methane content of 68.3% was obtained after pretreatment with HCl at pH 3, whereas for CH 3 COOH, the highest yield (350.2 ml/gVS) with 67.4% methane was observed after pretreatment at pH 1. OFMSW characteristics after each pretreatment step and their variation during the course of anaerobic digestion were also studied. An economic evaluation of all pretreatment scenarios was performed; out of which, pretreatment of OFMSW with HCl at pH 4-pH 6 yielded positive results in terms of net revenue gains.

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Free nitrous acid pre-treatment enhances anaerobic digestion of waste activated sludge and rheological properties of digested sludge: A pilot-scale study

Cited by 37 publications

References 42 publications

Improving wastewater management using free nitrous acid (FNA)

Improving wastewater management using free nitrous acid (FNA)

Structural Changes in Cell-Wall and Cell-Membrane Organic Materials Following Exposure to Free Nitrous Acid

Enhancement of biogas production from organic fraction of municipal solid waste using acid pretreatment

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