Biogas Generation from Sonicated Excess Sludge

Zawieja, Iwona; Włodarczyk, Renata; Kowalczyk, Mariusz

doi:10.3390/w11102127

Cited by 15 publications

(5 citation statements)

References 24 publications

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“…The biogas produced contains 60 -78% of methane with an average of 74%. This percentage of methane in biogas is similar to the percentage reported by Zawieja et al [44]. In fact, these researchers reported a higher percentage of 77% of methane in the biogas produced from sonicated excess sludge.…”

Section: Effect Of C/n Ratiosupporting

confidence: 90%

Bioenergy Potential and Kinetic of Biogas Production in Anaerobic Digestion of Slaughterhouse Effluent

Houndedjihou

Kodom

Tchakala

et al. 2022

Preprint

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A great amount of wastewater is generated each day from the slaughterhouse located in the harbor area (Togo). This amount of wastewater is a source of environmental pollution and degradation of water quality, as it is discharged with no treatment. The wastewater produced by slaughterhouses is biodegradable with a ratio between biological oxygen demand (BOD5) and chemical oxygen demand (COD) (BOD5/COD) > 0.5. Anaerobic co-digestion was used in this study to assess the bio-energy potential and kinetics of biogas production during processing. An effective anaerobic digestion design shows that over 90% of organic material was removed when inoculation and the carbon/nitrogen (C/N) ratio were adjusted. Biogas production was significantly affected by COD concentration, inoculation and C/N ratio. The cumulative volume of biogas increased from 415 mL to 2,150 mL as the substrate/inoculum (S/I) ratio has decreased from 2.028 to 0.337, while the cumulative volume of biogas increased from 1,140 mL to 5,250 mL as the C/N ratio increased from 6 to 22. The biogas produced has a high calorific value, as the methane content is 74% after simple purification with a concentrated solution of NaOH. Among the three kinetic models used to describe biogas production, a modified Gompertz model was found to be the best with R2 between 0.983 and 0.993. Then, the logistical model with R2 between 0.902 and 0.928 and the first order kinetic model with R2 between 0.552 and 0.704

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Section: Effect Of C/n Ratiosupporting

confidence: 90%

Bioenergy Potential and Kinetic of Biogas Production in Anaerobic Digestion of Slaughterhouse Effluent

Houndedjihou

Kodom

Tchakala

et al. 2022

Preprint

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“…During anaerobic digestion, more dissolved hydrolysate will provide more nutrient substrate for acidification and produce more VFAs . As shown in Figure , with the progress of anaerobic fermentation acid production, the total concentration of VFAs increases with time and shows a trend of increasing first and then decreasing.…”

Section: Resultsmentioning

confidence: 95%

Study on Dissolution Characteristics of Excess Sludge by Low-Temperature Thermal Hydrolysis and Acid Production by Fermentation

et al. 2020

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To investigate the dissolution characteristics of low-temperature thermal pretreatment conditions and the process of sludge fermentation to produce acid, the influence of thermal pretreatment temperature on the dissolution of excess sludge organic composition and the mechanism of cell crushing of sludge thermal pretreatment were analyzed by an experimental method, and the performance of acid production was explored by sludge fermentation after pretreatment at different temperatures. The performance of acid production by sludge fermentation after pretreatment at different temperatures was measured. The results proved that the soluble chemical oxygen demand (SCOD) shows the largest increase in dissolution rate (11.92%) at 70 °C and in dissolution quantity (6518.33 mg/L) at 90 °C. However, at 80 °C, the solubility of total organic carbon (TOC) is the highest (3224.47 mg/L), and at 70 °C, the best dissolution conditions for soluble carbohydrate (SC) and soluble protein (SP) reached 340.07 and 80.92 mg/L, respectively. The degree of sludge breaking starts to increase at 70 °C. Correlation analysis shows that dissolved organic matter is mainly derived from the cell wall and intracellular material and SP is mainly derived from intracellular material. Excitation–emission matrix spectra and parallel factor analysis (EEM-PARAFAC) divides the sludge dissolved organic matter (DOM) into five fluorescent components, including C1 (318/366) tyrosine, C2 (418/470) UVA humic acid, C3 (282/334) tryptophan substances, C4 (322/430) UVC humic acids, and C5 (314, 382, 454/526) UVA humic substances. Fermentation acid production experiment shows that the peak concentration is highest at 80 °C, the arrival time is 2 days, and the acid production type is butyric acid fermentation. Thus, it is proved that low-temperature thermal pretreatment promotes the process of acid-producing fermentation and has no effect on the type of fermentation. The optimal condition for hydrolytic dissolution and acid production under low-temperature thermal pretreatment is 80 °C.

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“…Pretreatment of sludge with ultrasonic frequencies has been shown to significantly enhance the disintegration of the sludge, and thereby accelerate anaerobic digestion [49][50][51]. However, attenuation of sound is proportional to the sound's frequency.…”

Section: Sonic Treatment Of Anaerobic Digestatementioning

confidence: 99%

“…Used as a pretreatment for the disintegration of sludge prior to anaerobic digestion, ultrasonication can vary considerably in duration and intensity. For instance, Zawiega found an intensity of 4.3 W cm −2 for 300 s to be optimal for solubilizing WAS in treating 0.5 L sludge samples prior to digestion in a 5 L reactor for 28 d [49]. Assuming that the WAS sample was diluted to a volume of 5 L, this represents a power input of 2580 J L −1 of WAS.…”

Section: Sonic Treatment Of Anaerobic Digestatementioning

confidence: 99%

Acoustic Stimulation of Anaerobic Digestion: Effects on Biogas Production and Wastewater Malodors

Loughrin¹,

Silva²,

Lovanh³

et al. 2022

Environments

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Wastewater created from various solid wastes and agricultural residues was treated by anaerobic digestion, and the biogas and wastewater odors were quantified. One digester was exposed to low-frequency sound (<5 kHz) from underwater loudspeakers, while the other received no sonic treatment. It was hypothesized that low-frequency sound, by accelerating the breakdown of sludge via mechanisms such as cavitation induction and mechanical vibration, and enhancing biogas production, could also affect the concentrations of wastewater odors. During warm seasons, biogas production from the sound-treated digester was 29% higher than that from the control digester, and 184% higher during the cool season. Malodors—Mainly consisting of typical aromatic malodorants such as p-cresol and skatole, aliphatic secondary ketones, and dimethyl disulfide—were quantified. In contrast to the findings for biogas production, little difference was found in the concentrations of volatile compounds in the control and sound-treated digestates. Concentrations of dimethyl polysulfides increased over time in both the control and sound-treated digestates, likely due to the use of recycled system effluent that contained precipitated elemental sulfur. The digestate contained considerable concentrations of volatile fatty acids and ammonium, but due to the near neutral pH of the digestate it was surmised that neither made appreciable contributions to the wastewater’s malodor. However, the volatile fatty acid concentrations were reduced by sonic treatment, which was not unexpected, since volatile fatty acids are precursors to methane. Therefore, although sonic treatment of the anaerobic digestate boosted biogas production, it did not markedly affect the wastewater malodors. The biosynthetic origins of wastewater malodors are discussed in this paper.

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Biogas Generation from Sonicated Excess Sludge

Cited by 15 publications

References 24 publications

Bioenergy Potential and Kinetic of Biogas Production in Anaerobic Digestion of Slaughterhouse Effluent

Bioenergy Potential and Kinetic of Biogas Production in Anaerobic Digestion of Slaughterhouse Effluent

Study on Dissolution Characteristics of Excess Sludge by Low-Temperature Thermal Hydrolysis and Acid Production by Fermentation

Acoustic Stimulation of Anaerobic Digestion: Effects on Biogas Production and Wastewater Malodors

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