Temperature phased anaerobic digestion increases apparent hydrolysis rate for waste activated sludge

Ge, Huoqing; Jensen, Paul D.; Batstone, Damien J.

doi:10.1016/j.watres.2010.11.042

Cited by 167 publications

(62 citation statements)

References 17 publications

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“…As reported earlier (3,7), the hydrolysis rate was almost double when the temperature was increased from 35°C to 55°C, and the improvement was transferred to the subsequent processes. Likewise, apparent methanogenic coefficients increased from 0.37 day Ϫ1 under mesophilic conditions (3) to 0.77 day Ϫ1 for acetoclastic methanogenesis and 1.4 day Ϫ1 for hydrogenotrophic methanogenesis under thermophilic digestion.…”

Section: Discussionsupporting

confidence: 75%

“…Thermophilic anaerobic digestion offers higher rates of destruction of pathogens and organic solids as well as potentially enhancing methane production. Several studies have shown that improvements in performance in thermophilic digestion are mainly due to an increase in hydrolysis coefficient (7)(8)(9), which determines speed of degradation, rather than to an increase in the fraction of degradable material. In addition to this advantage, the growth rates of thermophilic methanogens are 2 to 3 times higher than those of mesophilic methanogens (10).…”

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confidence: 99%

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Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

Jensen

Batstone

2013

Appl Environ Microbiol

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132

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This study investigated the process of high-rate, high-temperature methanogenesis to enable very-high-volume loading during anaerobic digestion of waste-activated sludge. Reducing the hydraulic retention time (HRT) from 15 to 20 days in mesophilic digestion down to 3 days was achievable at a thermophilic temperature (55°C) with stable digester performance and methanogenic activity. A volatile solids (VS) destruction efficiency of 33 to 35% was achieved on waste-activated sludge, comparable to that obtained via mesophilic processes with low organic acid levels (<200 mg/liter chemical oxygen demand [COD]). Methane yield (VS basis) was 150 to 180 liters of CH 4 /kg of VS added . According to 16S rRNA pyrotag sequencing and fluorescence in situ hybridization (FISH), the methanogenic community was dominated by members of the Methanosarcinaceae, which have a high level of metabolic capability, including acetoclastic and hydrogenotrophic methanogenesis. Loss of function at an HRT of 2 days was accompanied by a loss of the methanogens, according to pyrotag sequencing. The two acetate conversion pathways, namely, acetoclastic methanogenesis and syntrophic acetate oxidation, were quantified by stable carbon isotope ratio mass spectrometry. The results showed that the majority of methane was generated by nonacetoclastic pathways, both in the reactors and in off-line batch tests, confirming that syntrophic acetate oxidation is a key pathway at elevated temperatures. The proportion of methane due to acetate cleavage increased later in the batch, and it is likely that stable oxidation in the continuous reactor was maintained by application of the consistently low retention time.A naerobic digestion (AD) is a biological process which has been widely used for waste-activated sludge and primary sludge stabilization. It offers substantial advantages over alternative stabilization techniques, including low energy requirements, good-quality biosolids product, energy recovery in the form of methane (CH 4 ) gas, and the possibility of nutrient recovery (1, 2). Conventional anaerobic digesters are operated at a mesophilic temperature (35°C) with long hydraulic retention times (HRTs) of 15 to 20 days on waste-activated sludge (WAS), which is excess bacterial material and residual organics from combined aerobic treatment of wastewater, and more than 20 days on primary sludge (PS), which is the settled fraction from raw wastewater (1, 3, 4). Long treatment times are a key disadvantage of anaerobic digestion, requiring large tank volumes and, consequently, high capital cost, as well as increased mixing and maintenance costs. Therefore, reducing digester volume would strongly enhance the competitiveness of anaerobic technologies.Thermophilic anaerobic digestion (55°C to 70°C) is an alternative to conventional mesophilic anaerobic digestion (35°C). The majority of systems are operated at 55°C (5, 6), as higher temperatures can result in instability due to ammonia inhibition and reduced operability (2). Thermophilic anaerobic digestion offer...

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Section: Discussionsupporting

confidence: 75%

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confidence: 99%

Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

Jensen

Batstone

2013

Appl Environ Microbiol

Self Cite

132

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“…The average values were calculated after the bioreactors had achieved steady-state from the 37th day. The extent of solubilization was calculated as described by Ge et al (2011), which is expressed as…”

Section: Methodsmentioning

confidence: 99%

The effect of pH on solubilization of organic matter and microbial community structures in sludge fermentation

Maspolim

Zhou

Guo

et al. 2015

Bioresource Technology

169

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“…According to Song et al [20] and Roberts et al [23] two stage processes showed good performance in the effluent quality, methane yield, volatile solid reduction and process stability. Introducing a new process, the combination of mesophilic and thermophilic digestion, a co-phase system -temperature phased anaerobic digestion (TPAD) [20,24], demonstrated better digested sludge quality than that of a single-stage mesophilic or thermophilic anaerobic digestion.…”

Section: Introductionmentioning

confidence: 99%

Mesophilic-thermophilic fermentation process of waste activated sludge after hybrid disintegration

Grűbel

Machnicka

Nowicka

2014

Ecological Chemistry and Engineering S

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Abstract:The previously received results of individual processes of hydrodynamic and alkaline disintegration were decisive significant for the conducted research task. The combination of hydrodynamic cavitation (30 minutes duration of the process) and alkaline (pH ≈ 9) to the destruction of activated sludge caused a significant release of organic matter about 1383 mg/dm 3 in comparing to individual processes. Such increase in the SCOD value resulted in a significant growth the efficiency of biogas yield in a two-stage mesophilic-thermophilic processes. The increase in yield was from 26 to 38% depending on the volume of disintegrated sludge. The effect of the two-stage fermentation resulted activated sludge hygienisation. The microbiological analysis of the influence of the fermentation with the different volume of hybrid disintegrated sludge was based on microbiological indicators: Salmonella spp. and coliphages. The obtained results prove the effectiveness of the two-stage digestion process compared to single mesophilic fermentation which not always completely eliminates the above indicators.

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Temperature phased anaerobic digestion increases apparent hydrolysis rate for waste activated sludge

Cited by 167 publications

References 17 publications

Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

The effect of pH on solubilization of organic matter and microbial community structures in sludge fermentation

Mesophilic-thermophilic fermentation process of waste activated sludge after hybrid disintegration

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