Biogas Production from Waste Activated Sludge Using Cattle Dung Inoculums: Effect of Total Solid Contents and Kinetics Study

Compared to conventional mesophilic anaerobic digestion, thermophilic anaerobic digestion may offer attractive advantages such as higher volatile solid destruction efficiency, higher biogas generation, and higher disinfection effect and better dewater ability. In this study, two experiments of waste activated sludge were conducted to evaluate the influence of total solid and inoculums ratio on the biogas production and thermophilic (55±1°C) anaerobic process stability. In first experiment, the biogas production of 4 reactors with solid concentration of 6%, 8%, 10% and 12% respectively was observed. The biogas productions in 4 reactors were 4444 mL, 4891 mL, 5573 mL and 6327 mL respectively, the biogas productions per unit VS digested of each group were all above 360 mL/g and the methane content in biogas of each reactor was kept about 70%. During the operation, pH value in the reactor was kept between 6.5 and 8.4. In second experiment, the biogas production of 4 reactors with inoculums ratio of 20%, 30%, 40% and 50% respectively was observed. The biogas productions in 4 reactors were 4730 mL, 6630 mL, 6820 mL and 7175 mL respectively, the biogas productions per unit VS digested of each group were all above 340 mL/g and the methane content in biogas of each reactor was kept about 70%. During the operation, pH value in the reactor was kept between 6.4 and 8.6. Putting into consideration, the shortening of anaerobic digestion cycle, costs saving, and increasing economic benefits; choosing TS within the scope of 8-10%and inoculums ratio within the scope of 30-40% are more recommended. And the results showed that thermophilic anaerobic digestion process for waste activated sludge could be operated steadily.

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Co-digestion of waste activated sludge and agricultural straw waste for enhanced biogas production

Bioresource Technology Reports ◽

10.1016/j.biteb.2021.100769 ◽

2021 ◽

pp. 100769

Author(s):

Rasika M. Potdukhe ◽

Nidhi Sahu ◽

Atya Kapley ◽

Rakesh Kumar

Keyword(s):

Activated Sludge ◽

Biogas Production ◽

Waste Activated Sludge

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Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

International Journal of Chemical Engineering ◽

10.1155/2019/5138060 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9

Author(s):

Quang-Minh Nguyen ◽

Duy-Cam Bui ◽

Thao Phuong ◽

Van-Huong Doan ◽

Thi-Nham Nguyen ◽

...

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Activated Sludge ◽

Removal Efficiency ◽

Biogas Production ◽

Cod Removal ◽

Septic Tank ◽

Waste Activated Sludge ◽

Digestion Process ◽

Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

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Microbial community dynamics linked to enhanced substrate availability and biogas production of electrokinetically pre-treated waste activated sludge

Bioresource Technology ◽

10.1016/j.biortech.2016.07.029 ◽

2016 ◽

Vol 218 ◽

pp. 761-770 ◽

Cited By ~ 8

Author(s):

Maria Westerholm ◽

Sam Crauwels ◽

Sofie Houtmeyers ◽

Ken Meerbergen ◽

Maarten Van Geel ◽

...

Keyword(s):

Microbial Community ◽

Activated Sludge ◽

Community Dynamics ◽

Biogas Production ◽

Waste Activated Sludge ◽

Substrate Availability ◽

Microbial Community Dynamics

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Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility

Water Science & Technology ◽

10.2166/wst.2013.692 ◽

2013 ◽

Vol 69 (2) ◽

pp. 269-277 ◽

Cited By ~ 15

Author(s):

C. Da Ros ◽

C. Cavinato ◽

F. Cecchi ◽

D. Bolzonella

Keyword(s):

Activated Sludge ◽

Biogas Production ◽

Oxygen Demand ◽

Pilot Scale ◽

Waste Activated Sludge ◽

Organic Loading ◽

Operational Conditions ◽

Loading Rates ◽

Thermophilic Conditions ◽

Soluble Chemical Oxygen Demand

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

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