Effect of sludge biochar as an additive in thermophilic anaerobic digestion
| dc.contributor.author | Thakur , Aashutosh Kumar | |
| dc.contributor.department | Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE) | sv |
| dc.contributor.department | Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE) | en |
| dc.contributor.examiner | Wilén, Britt-Marie | |
| dc.contributor.supervisor | Modin, Oskar | |
| dc.date.accessioned | 2024-07-03T09:55:28Z | |
| dc.date.available | 2024-07-03T09:55:28Z | |
| dc.date.issued | 2024 | |
| dc.date.submitted | ||
| dc.description.abstract | The production of sewage sludge, the main byproduct of municipal wastewater treatment plants (WWTPs), is likely to increase due to growing urban populations and stricter effluent disposal regulations. Anaerobic digestion (AD) is among the most widely adopted methods in municipal WWTPs for the treatment and stabilisation of sewage sludge. The AD process has been found to perform optimally in two temperature regimes: mesophilic (35–40 °C) and thermophilic (55–60 °C), and it offers the advantage of recovering clean energy in the form of methane-rich biogas which can help offset the plant’s energy costs. Given the increasing constraints on energy supply, exploring ways to enhance biogas yield from AD becomes important. Sewage sludge pyrolysis is another technology that has received growing attention as an alternative method of sludge management. It involves heating the dewatered and dried sewage sludge at high temperatures (300–800 °C) in the absence of oxygen, producing sludge biochar as a byproduct. With properties that can favour microorganism growth and metabolism, sludge biochar could potentially improve anaerobic digestion performance when used as an additive during the digestion process. This thesis investigates the impact of using sludge biochar as an additive in thermophilic anaerobic digestion of easily biodegradable substrates, specifically microcrystalline cellulose (MC) and sodium acetate (SA). A batch anaerobic digestion experiment was conducted over 49 days in two consecutive phases: the first phase using MC and the second phase using SA as substrates. Sludge biochar (SB) and synthetic graphite (SG) were used as additives in two different reactor groups to assess their impact on the cumulative biogas yield. Results from Phase 1 showed that the overall biogas yield in the SB and SG dosed reactors exceeded the control group by 1.5% and 2.1% respectively, indicating a minimal impact of SB on thermophilic anaerobic digestion of MC. However, results from Phase 2 using SA as the substrate showed that biogas yield in the SB and SG dosed reactors exceeded the control by around 21% and 8.5% respectively, indicating a much greater impact of the additive. This suggests that SB could have influenced the methanogenesis reactions in the second phase, resulting in an increase in total biogas yield. While SB shows potential as an additive for improving anaerobic digestion performance, further investigations are needed to understand the enhancement mechanism and its potential application with sewage sludge digestion. | |
| dc.identifier.coursecode | ACEX30 | |
| dc.identifier.uri | http://hdl.handle.net/20.500.12380/308210 | |
| dc.language.iso | eng | |
| dc.setspec.uppsok | Technology | |
| dc.subject | wastewater treatment plant | |
| dc.subject | sewage sludge | |
| dc.subject | anaerobic digestion | |
| dc.subject | sludge pyrolysis | |
| dc.subject | biochar | |
| dc.subject | sludge biochar | |
| dc.subject | biogas | |
| dc.subject | methanogenesis | |
| dc.title | Effect of sludge biochar as an additive in thermophilic anaerobic digestion | |
| dc.type.degree | Examensarbete för masterexamen | sv |
| dc.type.degree | Master's Thesis | en |
| dc.type.uppsok | H | |
| local.programme | Infrastructure and environmental engineering (MPIEE), MSc |