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035 _a.b12508366
099 9 _aAIT Thesis no.EV-26-24
100 1 _aKhan, Tasbiha
245 1 0 _aApplication of anaerobic digestate-derived biochar in the semi-continuous anaerobic digestion of sewage sludge and food waste
260 _aPathum Thani, Thailand :
_bAsian Institute of Technology,
_c2026
300 _a112 leaves :
_bill.+
_e1 online resource
490 1 _aThesis ;
_vno. EV-26-24
500 _aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management
502 _aThesis (M. Eng.) - Asian Institute of Technology, 2026
520 _aDigestate-derived biochar was used to examine the effectiveness of semi-continuous anaerobic co-digestion of food waste and sewage sludge under mesophilic conditions. Even though anaerobic digestion is a common method for producing biogas, instability brought on by acid buildup, ammonia inhibition, and varying organic loading rates (OLR) frequently limits its effectiveness. In order to overcome these obstacles, biochar made from anaerobic digestate was used to improve methane production and system stability. At 35 ± 1°C, two identical lab-scal Continuous Stirred Tank Reactors with working volumes of 6 and 8 L were used. Reactor R1 received biochar (0.8, 1, 2, and 5 g/L), and reactor R2 was used as a control. To evaluate performance under both stable and stressful situations, reactors were run with increasing OLR. TS, VS, pH, alkalinity, ammonia nitrogen, VFAs, biogas generation, and methane concentration were among the important variables that were tracked. SPSS was used for statistical analysis. Reactor stability and performance were greatly enhanced by the addition of biochar; R1 maintained a more constant pH (6.98{u2013}7.81) than R2 (6.71{u2013}7.35) and demonstrated less ammonia accumulation (95.19{u2013}203.03 vs. 129.28{u2013}319.46 mg NH₄-N/L). Lower FOS/TAC ratios (0.27{u2013}0.36) and lower VFA levels (476{u2013}792 mg/L) in R1 compared to R2 (up to 0.55 and 1148 mg/L) demonstrate improved process stability. Additionally, R1 produced more biogas, with methane content reaching around 53% compared to about 42% in R2, especially at ideal biochar dosages of 1-2 g/L. Better reactor performance was also demonstrated by improved substrate degradation (TS up to 3.92). Biochar's high surface area and porous structure, which encourage microbial activity and DIET, are responsible for these improvements; 500°C biochar exhibits the best overall performance. Overall, digestate-derived biochar is an effective additive for improving anaerobic co-digestion stability and methane production. Future research should focus on optimizing biochar dosage, long-term performance, and microbial mechanisms under varying operating conditions.
650 0 _aBiochar
650 0 _aSewage sludge
700 0 _aGhimire, Anish,
_eChairperson
700 1 _aCruz, Simon Guerrero,
_eExamination Committee
700 1 _aXue, Wenchao,
_eExamination Committee
710 2 _aPMU-KPCIP-AIT Scholarship,
_eScholarship Donor
810 2 _aAsian Institute of Technology.
_tThesis ;
_vno. EV-26-24
856 4 0 _3Full-Text
_uhttp://203.159.5.9/ait-thesis/detail.php?q=B24468
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