Table 4 Comparison of data from the foaming digesters D1 and D2 (biogas plant BP A)
From: Foam formation in full-scale biogas plants processing biogenic waste
Time of sampling | Two weeks before foaming | Day 1 of foaming | One week after foaming | ||||
|---|---|---|---|---|---|---|---|
Digester | Index | D1 | D2 | D1 | D2 | D1 | D2 |
TS [%] | O | 3.53 | 1.77 | 4.17 | 3.45 | 3.25 | 2.85 |
VS [% TS] | O | 56.5 | 33.5 | 66.0 | 64.4 | 52.1 | 45.6 |
pH [−] | CE | 8.08 | 8.06 | 8.12 | 8.03 | 7.87 | 8.12 |
VFA/TIC [−] | CE/CA | 0.16 | 0.13 | 0.11 | 0.12 | 0.09 | 0.11 |
NH4-N [g/L] | F | 2.81 | 3.09 | 2.50 | 2.06 | 2.04 | 2.31 |
Total organic carbon [g/L] | B | 6.52 | 5.44 | 11.1 | 8.68 | 9.10 | 11.26 |
Total nitrogen [g/L] | B | 4.31 | 4.32 | 4.62 | 4.29 | 4.23 | 4.31 |
Crude protein [g/L] | CA | 9.34 | 7.62 | 13.2 | 13.9 | 13.6 | 12.5 |
Acetic acid [mg/L] | F | 159 | 182 | 31.4 | 26.5 | 29.5 | 76.7 |
Propionic acid [mg/L] | F | <1 | <1 | <1 | <1 | <1 | <1 |
Butyric acid [mg/L] | F | <1 | <1 | <1 | <1 | <1 | <1 |
Calcium [mg/L] | F | 12.0 | 48.0 | 41.0 | 58.6 | 43.5 | 21.0 |
Magnesium [mg/L] | F | 1.41 | 7.23 | 5.05 | 6.06 | 5.91 | 2.31 |
Phosphorus [mg/L] | F | 300 | 284 | 316 | 305 | 248 | 190 |
Potassium [mg/L] | F | 1,148 | 1,188 | 1,130 | 1,159 | 1,096 | 1,190 |
Sulfur [mg/L] | F | 301 | 297 | 379 | 332 | 345 | 324 |
Surface tension [mN/m] | CE | 57.7 | 57.0 | 60.7 | 60.2 | 58.0 | 57.0 |