Effect of increasing the surface area of primary sludge on anaerobic digestion at low temperature

Halalsheh, Maha; Kassab, Ghada; Yazajeen, Haifa; Qumsieh, S.; Field, James A.

doi:10.1016/j.biortech.2010.08.075

Cited by 31 publications

(8 citation statements)

References 19 publications

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“…However, reported results on mixing impact and optimal intensity remain inconclusive. While vigorous mixing has been suggested to improve the biodegradation of volatile solids by increasing their solubility and area of contact with bacteria (Halalsheh et al, 2011), it has been equally reported to hinder the formation of flocks, where syntrophic microbial interactions can take place, and cause propionate accumulation resulting in lower removal efficiency (Suwannoppadol et al, 2011). In comparison, systems with moderate mixing (80 rpm) seem to have high stability and are able to absorb the disturbance of a shock load, even when stratification occurs (Gomez et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

Ghanimeh

Al-Sanioura

Saikaly

et al. 2018

Journal of Environmental Management

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This study examines the stability and efficiency of thermophilic anaerobic digesters treating food waste under various mixing velocities (50-160 rpm). The results showed that high velocities (120 and 160 rpm) were harmful to the digestion process with 18-30% reduction in methane generation and 1.8 to 3.8 times increase in volatile fatty acids (VFA) concentrations, compared to mild mixing (50 and 80 rpm). Also, the removal rate of soluble COD dropped from 75 to 85% (at 50-80 rpm) to 20-59% (at 120-160 rpm). Similarly, interrupted mixing caused adverse impacts and led to near-failure conditions with excessive VFA accumulation (15.6 g l), negative removal rate of soluble COD and low methane generation (132 ml gVS). The best efficiency and stability were achieved under mild mixing (50 and 80 rpm). In particular, the 50 rpm stirring speed resulted in the highest methane generation (573 ml gVS). High-throughput sequencing of 16S rRNA genes revealed that the digesters were dominated by one bacterial genus (Petrotoga; phylym Thermotogae) at all mixing velocities except at 0 rpm, where the community was dominated by one bacterial genus (Anaerobaculum; phylum Synergistetes). The Petrotoga genus seems to have played a major role in the degradation of organic matter.

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Section: Introductionmentioning

confidence: 99%

Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

Ghanimeh

Al-Sanioura

Saikaly

et al. 2018

Journal of Environmental Management

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“…The large surface area aids the build-up of suspended solids or scum if mixing is limited [34]. Moreover, mixing is important to (i) provide even temperature distribution and proper diffusion or spread of metabolic intermediates [13], (ii) enable sufficient contacts between micro-organism and nutrients [18], and (iii) improve hydrolysis and increase substrate surface area [15].…”

Section: Effect Of Baffles On Mixing and Reactor Performancementioning

confidence: 99%

“…The effect of mixing on the anaerobic digestion process has been studied by various authors. The requirement for digesters to be adequately and sufficiently mixed has been supported by many authors [12][13][14][15], and challenged by many other authors [16][17][18][19]. Lindmark et al [20] concluded in a review that an intermittent mixing mode is better than continuous mixing, and shorter mixing durations are preferable for higher biogas production and from an energy point of view.…”

Section: Introductionmentioning

confidence: 99%

Development of an Optimised Chinese Dome Digester Enables Smaller Reactor Volumes; Pilot Scale Performance

2019

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Chinese dome digesters are usually operated at long hydraulic retention times (HRT) and low influent total solids (TS) concentration because of limited mixing. In this study, a newly optimised Chinese dome digester with a self-agitating mechanism was investigated at a pilot scale (digester volume = 500 L) and compared with a conventional Chinese dome digester (as blank) at 15% influent TS concentration at two retention times (30 and 40 days). The reactors were operated at ambient temperature: 27–33 °C. The average specific methane production, volatile fatty acids and percentage of volatile solids (VS) reduction are 0.16 ± 0.13 and 0.25 ± 0.05L CH4/g VS; 1 ± 0.5 and 0.7 ± 0.3 g/L; and 51 ± 14 and 57 ± 10% at 40 days HRT (day 52–136) for the blank and optimised digester, respectively. At 30 days HRT (day 137–309) the results are 0.19 ± 0.12 and 0.23 ± 0.04 L CH4/g VS; 1.2 ± 0.6 and 0.7 ± 0.3 g/L; and 51 ± 9 and 58 ± 11.6%. Overall, the optimised digester produced 40% more methane than the blank, despite the high loading rates applied. The optimised digester showed superior digestion treatment efficiency and was more stable in terms of VFA concentration than the blank digester, can be therefore operated at high influent TS (15%) concentration.

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“…Reduction in average particle diameter (20 to 5 μm) was observed, along with increased specific methanogenic activity (0.16 to 0.41 g COD/g VSSd);however, there was insignificant COD removal. Powdered activated carbon improved the effect of slug flow on membrane fouling, as membrane flux increased from 16 L/m 2 h to 34 L/m 2 h.The effect of sludge surface area on anaerobic digestion at low temperature (15°C) was investigated using reactors with SRTs of 65 and 30 days(Halalsheh et al, 2011). Shear forces due to six different mixing velocities at each set affected particle size distribution and caused different sludge surface areas.…”

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confidence: 99%

Anaerobic Processes

Kasiri¹,

Mah²,

Zhang³

et al. 2012

Water Environment Research

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The anaerobic processes literature review contains a comprehensive discussion of articles published in 2011, including both original research and review articles. Specific attention is paid to studies on design and optimization of systems using anaerobic processes, as well as characterizing the microflora involved in such processes.This year's anaerobic processes literature review is divided into the following sections:biogas treatment and use, integrated approaches, modeling advances, process technology, hydrogen production, microbiology, anammox, treatability studies, and toxicity.

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Effect of increasing the surface area of primary sludge on anaerobic digestion at low temperature

Cited by 31 publications

References 19 publications

Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

Development of an Optimised Chinese Dome Digester Enables Smaller Reactor Volumes; Pilot Scale Performance

Anaerobic Processes

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