Abrogating the inhibitory effects of volatile fatty acids and ammonia in overloaded food waste anaerobic digesters via the supplementation of nano-zero valent iron modified biochar

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.

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Anaerobic digestion of food waste to volatile fatty acids and hydrogen at high organic loading rates in immersed membrane bioreactors

Renewable Energy ◽

10.1016/j.renene.2020.01.138 ◽

2020 ◽

Vol 152 ◽

pp. 1140-1148 ◽

Cited By ~ 6

Author(s):

Steven Wainaina ◽

Mukesh Kumar Awasthi ◽

Ilona Sárvári Horváth ◽

Mohammad J. Taherzadeh

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Food Waste ◽

Volatile Fatty Acids ◽

Membrane Bioreactors ◽

Organic Loading ◽

Loading Rates

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Enhanced reductive defluorination and inhibited infiltration of fluoroglucocorticoids in a river receiving reclaimed water amended by nano zero-valent iron-modified biochar: Performance and mechanisms

Bioresource Technology ◽

10.1016/j.biortech.2020.123127 ◽

2020 ◽

Vol 306 ◽

pp. 123127 ◽

Cited By ~ 2

Author(s):

Yayun Xiang ◽

Eldon R. Rene ◽

Xiaoxiu Lun ◽

Weifang Ma

Keyword(s):

Reclaimed Water ◽

Zero Valent Iron ◽

Modified Biochar ◽

Nano Zero Valent Iron

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Recovery of volatile fatty acids (VFA) from complex waste effluents using membranes

Water Science & Technology ◽

10.2166/wst.2013.717 ◽

2013 ◽

Vol 69 (3) ◽

pp. 495-503 ◽

Cited By ~ 32

Author(s):

M.-P. Zacharof ◽

R. W. Lovitt

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Butyric Acid ◽

Volatile Fatty Acids ◽

Agricultural Waste ◽

Permeate Flux ◽

Anaerobic Digesters ◽

Waste Effluents

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.

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