Modelling anaerobic digestion acclimatisation to a biodegradable toxicant: application to cyanide

2006 ◽  
Vol 54 (4) ◽  
pp. 129-137 ◽  
Author(s):  
U. Zaher ◽  
M.S. Moussa ◽  
I.N. Widyatmika ◽  
P. van Der Steen ◽  
H.J. Gijzen ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Inorganic Nitrogen ◽  
Degradation Pathway ◽  
Anaerobic Sludge ◽  
Buffer Solution ◽  
Cyanide Toxicity ◽  
Cyanide Degradation ◽  
Hydrogenotrophic Methanogens ◽  
Cassava Wastewater ◽  
Equilibrium Calculations

The observed acclimatisation to biodegradable toxicants in anaerobic cassava wastewater treatment is explained by modelling anaerobic cyanide degradation. A complete degradation pathway is proposed for cyanide. Cyanide degradation is modelled as enzymatic hydrolysis to formate and ammonia. Ammonia is added to the inorganic nitrogen content of the digester while formate is degraded by the hydrogenotrophic methanogens. Cyanide irreversible enzyme inhibition is modelled as an inhibition factor to acetate uptake processes. Cyanide irreversible toxicity is modelled as a decay factor to the acetate degraders. Cyanide as well as added phosphorus buffer solution were considered in the chemical equilibrium calculations of pH. The observed reversible effect after acclimatisation of sludge is modelled by a population shift between two aceticlastic methanogens that have different tolerance to cyanide toxicity. The proposed pathway is added to the IWA Anaerobic Digestion Model no.1 (ADM1). The ADM1 model with the designed extension is validated by an experiment using three lab-scale upflow anaerobic sludge bed reactors which were exposed to different cyanide loadings.

scholarly journals Anaerobic biodegradation of cassava wastewater under different temperatures and inoculums

2019 ◽  
Vol 10 (1) ◽  
pp. 65-76
Author(s):  
Miriam Cleide Cavalcante de Amorim ◽  
Paula Tereza De Souza Silva ◽  
Patricia Silva Barbosa ◽  
Nayara Evelyn Montefusco
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Semiarid Region ◽  
Anaerobic Sludge ◽  
Bovine Rumen ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Cassava Wastewater ◽  
Kinetics Of ◽  
Goat Rumen

The production of starch generates, as a by-product, the cassava wastewater (manipueira), which can be treated by anaerobic digestion to provide biogas and minimize its polluting potential. The most commonly utilized biomass in the anaerobic digestion is the anaerobic sludge. The literature presents, as an alternative to sludge, bovine manure and ruminal fluids, being scarce the studies with the cassava wastewater. This research evaluated the influence of temperature on the microbial ability of cattle and goat rumen in anaerobically biodegrading the manipueira in substitution to the anaerobic sludge. The cattle and goat rumen specific methanogenic activities (SMA) were compared with that of the anaerobic sludge. Subsequently, by using the inoculum which had the best SMA results, cassava wastewater biodegradability tests were performed, investigating the kinetics of the organic matter removal and methane production at 32 ° C and 39 ° C. The bovine rumen presented better results in the SMA (0,315 g COD-CH4 g VSS.d-1) and methane production (1,026 mL). The temperature of 32 °C did not influence the activity of bovine ruminal inoculum as the kinetics of the biodegradation of the manipueira did not differ for the evaluated temperatures (0.1799 d-1 at 32°C and 0.1781 d-1 at 39°C). Bovine rumen achieved glucose reduction of 76% and 80% and methane yield of 77% and 79% for the tests at 32°C and 39°C, respectively. It is inferred that this type of inoculum might be used in reactors of anaerobic digestion processes for the treatment of the cassava wastewater at the ambient temperature of the semiarid region.

Simulation of the Impact of Higher Ammonia Recycle Loads Caused by Upgrading Anaerobic Sludge Digesters

2005 ◽  
Vol 40 (4) ◽  
pp. 491-499 ◽  
Author(s):  
Jeremy T. Kraemer ◽  
David M. Bagley
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Content Increase ◽  
Limited Information ◽  
Dynamic Simulations ◽  
Treatment Train ◽  
Temperature Liquid ◽  
The Impact

Abstract Upgrading conventional single-stage mesophilic anaerobic digestion to an advanced digestion technology can increase sludge stability, reduce pathogen content, increase biogas production, and also increase ammonia concentrations recycled back to the liquid treatment train. Limited information is available to assess whether the higher ammonia recycle loads from an anaerobic sludge digestion upgrade would lead to higher discharge effluent ammonia concentrations. Biowin, a commercially available wastewater treatment plant simulation package, was used to predict the effects of anaerobic digestion upgrades on the liquid train performance, especially effluent ammonia concentrations. A factorial analysis indicated that the influent total Kjeldahl nitrogen (TKN) and influent alkalinity each had a 50-fold larger influence on the effluent NH3 concentration than either the ambient temperature, liquid train SRT or anaerobic digestion efficiency. Dynamic simulations indicated that the diurnal variation in effluent NH3 concentration was 9 times higher than the increase due to higher digester VSR. Higher recycle NH3 loads caused by upgrades to advanced digestion techniques can likely be adequately managed by scheduling dewatering to coincide with periods of low influent TKN load and ensuring sufficient alkalinity for nitrification.

Anaerobic Digestion of Cassava Wastewater Pre-treated by Fungi

2013 ◽  
Vol 169 (8) ◽  
pp. 2457-2466 ◽  
Author(s):  
Paula Loureiro Paulo ◽  
Thais Adriana Colman-Novaes ◽  
Laynara Dayene Soares Obregão ◽  
Marc Árpád Boncz
Keyword(s):  
Anaerobic Digestion ◽  
Cassava Wastewater

Anaerobic digestion of excess activated sludge with ozone pretreatment

2003 ◽  
Vol 47 (12) ◽  
pp. 207-214 ◽  
Author(s):  
R. Goel ◽  
T. Tokutomi ◽  
H. Yasui
Keyword(s):  
Anaerobic Digestion ◽  
Ozone Treatment ◽  
Anaerobic Sludge ◽  
Methane Recovery ◽  
Sludge Disposal ◽  
Ozone Dose ◽  
Significant Difference ◽  
Attractive Option ◽  
Ozone Pretreatment

Source minimization of excess sludge production by economical means can be considered an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for a process that combines the oxidative ozone pretreatment with anaerobic sludge digestion are described. The ozone pretreatment solubilized around 19% and 37% of the solids at 0.015 and 0.05 gO3/gTS ozone dose. The solubilization ratios during ozonation did not show any significant difference for the sludge concentrations ranging from 1.8-2.6%. The TVS concentrations after ozone treatment were observed to be about 3% lower than the feed sludge concentrations suggesting only partial mineralization during ozonation. The ozone pretreatment resulted in improved solid reduction efficiencies during anaerobic digestion leading to higher methane recovery. The TVS removal efficiencies during anaerobic digestion were observed to increase by a maximum of 35-90% depending on the applied ozone dose during ozone pretreatment. The improvement in TVS degradation efficiency at different applied ozone doses correlated well with the extent of solubilization during ozonation. Long-term data also suggested that biomass acclimation to ozonated sludge was necessary before higher degradation efficiencies could be achieved.

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