Table 1.
Overview of sampled digester types and input feeding based on descriptive data
| Sample | Digester type | Input materials | Plant configuration |
|---|---|---|---|
| LB-Schmölln | Leach-bed batch digester | Silage, straw, cow manure | Batch process (11 batches) |
| Digester volume: 11 × 800 m3 | |||
| Leachate tank: 1000 m3 | |||
| Batch process duration: 26–29 days | |||
| Gas production: 0.7 m3/m3 × day | |||
| OLR: 1.3 kg × VS/m3 × day | |||
| CD-Jena | Two-stage digester (vertical plug flow reactor/stirred tank) | Silage, farm manure, Livestock farming waste | Two-stage process |
| Stage 1 (plug flow): 790 m3 | |||
| Stage 2 (CSTR): 2000 m3 | |||
| Stage 3 (final storage tank): 3800 m3 | |||
| HRT: 87 days | |||
| Gas production: 1.2 m3/m3 × day | |||
| OLR: 3.0 kg × VS/m3 × day | |||
| SS-Jena | Completely mixed tank digester | Mono-digestion of municipal sewage sludge | Single stage process (2 digesters) |
| Digester volume: 2 × 2000 m3 | |||
| HRT: 21 days | |||
| Gas production: 0.6 m3/m3 × day | |||
| OLR: 1.8 kg × VS/m3 × day | |||
| SS-Weimar | Completely mixed tank digester | Mono-digestion of municipal sewage sludge | Single stage process |
| Digester volume: 3200 m3 | |||
| HRT: 29 days | |||
| Gas production: 0.6 m3/m3 × day | |||
| OLR: 0.96 kg × VS/m3 × day | |||
| LB-Schlossvippach | Leach-bed batch digester | Cow manure, straw, feed residues | Batch process (8 batches) |
| Leachate tank: 1000 m3 | |||
| Digester volume: 8 × 330 m3 | |||
| Batch process duration: 32–35 days | |||
| Gas production: 0.5 m3/m3 × day | |||
| OLR: 2.1 kg × VS/m3 × day | |||
| SS-Rudolstadt | Completely mixed tank digester | Co-digestion of municipal and industrial sewage sludge with seasonally available co-substrates (biodiesel waste) | Single-stage process (2 digesters) |
| Digester volume: 2 × 2000 m3 | |||
| HRT: 25 days | |||
| Gas production: 0.3 m3/m3 × day | |||
| OLR: 0.54 kg × VS/m3 × days | |||
| LB-Saalfeld | Leach-bed batch digester | Organic fraction of municipal solid waste | Batch process (9 batches) |
| Digester volume: 9 × 826 m3 | |||
| Leachate tank: 1060 m3 | |||
| Batch process duration: 33 days | |||
| Gas production: 0.7 m3/m3 × day | |||
| OLR: 0.9 kg × VS/m3 × day |
Gas production is given in cubic meter of produced gas per cubic meter of sludge per day
HRT hydraulic retention time, CSTR continuous stirred-tank reactor, OLR organic loading rate