Enhanced biogas production by anaerobic co-digestion from a trinary mix substrate over a binary mix substrate

Abstract

The synergetic enhancement of mesophilic anaerobic co-digestion of trinary and binary mix of organic fraction of municipal solid waste (OFMSW) + primary sludge (PS) + thickened waste activated sludge (TWAS) as substrates was investigated through batch biological methane potential (BMP) and semi-continuous flow reactor tests. Cumulative biogas yield (CBY) yield for the binary mix of OFMSW:TWAS was 555, 580, and 660 mL/g volatile solids (VS)added for an OFMSW:TWAS ratio of 25:75, 50:50, and 75:25, respectively, which was 48, 78.5, and 140% higher than the calculated expected biogas (CEB) yield from the corresponding individual substrates. The trinary mixture of OFMSW:TWAS:PS at ratios of 25:37.5:375.5, 50:25:25 and 75:12.5:12.5 was able to produce 680, 710 and 780 mL/g VSadded, respectively, which was 25.5, 62.0 and 135.6% more biogas than the calculated expected biogas yield from the corresponding individual substrates. Cumulative methane yield (CMY) of trinary mixtures was also higher than the corresponding binary mixtures (20, 27, and 12 % increase for OFMSW:TWAS:PS at a ratio of 25:37.5:37.5, 50:25:25, and 75:12.5:12.5 compared to the binary mix of OFMSW:TWAS at a ratio of 25:75, 50:50, and 75:25, respectively). Methane content of the biogas varied from 54 to 57%. The results from semi-continuous flow anaerobic reactors under hydraulic retention times (HRT) of 15, 10 and 7 days supported the results of batch biological methane potential tests. The results were conclusive that enhancement in biogas production was noticeably higher from the co-digestion of trinary mix of organic fraction of municipal solid waste+ thickened waste activated sludge + primary sludge than the binary mix organic fraction of municipal solid waste+thickened waste activated sludge or thickened waste activated sludge+primary sludge with concomitant improvements in VS removal and biodegradability for tri-digestion of organic fraction of municipal solid waste, thickened waste activated sludge and primary sludge.

Simultaneous Synergy in CH4 Yield and Kinetics: Criteria for Selecting the Best Mixtures during Co-Digestion of Wastewater and Manure from a Bovine Slaughterhouse

“…This highlights the advantage of multi-component AcoD over binary ones, both in the final CH 4 yield and in the kinetics of production. Similar findings were found by Ara et al (2015) [18] during AcoD of organic fraction of municipal solid waste, primary sludge and thickened waste activated sludge; the ternary mixtures exhibited CH 4 yields between 12 and 27% higher than binary mixtures. Additionally, Castro-Molano et al (2018) [39] observed higher φy factors in ternary mixtures (25-167%) than binary mixtures (5-68%) when chicken manure was co-digested with industrial wastes.…”

“…Usually, AcoD studies have evaluated the synergy between co-substrates focused on CH 4 yield [18,19] while the kinetics (rate of degradation) in most cases is evaluated with mathematical models, without determining whether there is synergy in the kinetic factors [17,20]. Thus far, three methodologies have been published to assess synergy in kinetic parameters.…”

Synergistic effect of co-digestion to enhance anaerobic degradation of catering waste and orange peel for biogas production

“…Considering these negative effects, some interventions are needed for an effective processing system (Sosnowski et al, 2003). Currently, attention has shifted towards co-digestion of a mixture of substrates, as reported in recent literature (Ajeej et al, 2015; Anjum et al, 2016c; Ara et al, 2015; Yalcinkaya and Malina, 2015). The co-digestion process is very obliging in improving nutrient availability, organic load and diluting toxic compounds; furthermore, the supplementary effect of microbial synergism also improves the digestion process.…”

New findings on the anaerobic co-digestion of thermally pretreated sludge and food waste: laboratory and pilot-scale studies

“…The biogas production curves using different substrate/co-substrate ratios can be found in supplementary material (Figure S1). The biogas yield increased significantly (ANOVA, F (7,16) ¼ 7.087, p ¼ 0.0006) with the FW proportion from 512.4 + 5.5 ml•g SV s À1 (controlno FW) to 629.2 + 67.1 ml• gSV s À1 (FW only) (Ara et al 2015). While biogas productivity showed no statistically significant differences (ANOVA, F (6,14) ¼ 2.40, p ¼ 0.08) between the conditions studied (Tale S1, Supplementary material).…”

“…Our results are consistent with those reported by Heo et al (2003), which determined that ACoD at a 50/50 FW/WAS ratio was optimal in terms of biogas production. Using the same SS/OFMSW (Organic Fraction of Municipal Solid Waste) ratio, Ara et al (2015) achieved similar improvements in biogas productivity, although lower HRTs were applied. While Caffaz et al (2008) worked on a pilot scale two 200 L digesters for the ACoD of WAS and OFMSW at an increasing OLR which led to improvements in the yield and biogas productivity.…”