Table 1 Process performance parameters of digesters and post-digesters at full-scale biogas plants at the time of sampling
| Plant | Sample point | TS (%) | VS (% of TS) | VS red. (%) | pH | NH4+-N (g/kg) | NH3-N (g/kg) | VFA (mg/L) |
|---|---|---|---|---|---|---|---|---|
| FW1 | D | 5.3 | 73.6 | 70 | 7.8 | 3.4 | 0.34 | 80 |
| PD | 4.3 | 71.5 | 77 | 7.8 | 3.6 | 0.35 | 40 | |
| FW2 | D | 3.9 | 66.7 | 48 | 7.9 | 3.6 | 0.31 | 1360 |
| PD | 3.8 | 65.5 | 50 | 7.9 | 3.8 | 0.35 | 190 | |
| FW3 | D | 4.1 | 69.6 | 75 | 7.5 | 2.4 | 0.10 | 40 |
| PD | 3.8 | 67.9 | 77 | 7.7 | 2.5 | 0.13 | 20 | |
| FW-TD | D | 11.6 | 66.6 | 65 | 7.8 | 3.8 | 0.74 | 8450 |
| AW1 | D | 10 | 88.2 | 67 | 7.6 | 2.4 | 0.12 | 150 |
| PD | 7.2 | 86.0 | 78 | 7.5 | 2.3 | 0.08 | 60 | |
| AW2 | D | 8.6 | 81.8 | 66 | 7.3 | 3.3 | 0.09 | 320 |
| PD | 6.3 | 77.3 | 77 | 7.8 | 2.4 | 0.20 | 2 | |
|
AWM-A AWM-B | D | 7.3 | 74.1 | 62 | 7.9 | 2.0 | 0.18 | 370 |
| D | 7.4 | 74.2 | 62 | 7.8 | 3.4 | 0.26 | 420 | |
| WWTP1 | D | 3.2 | 66.5 | 55 | 7.9 | 1.4 | 0.15 | 20 |
|
WWTP2-A WWTP2-B | D | 1.6 | 64.5 | 63 | 7.2 | 0.8 | 0.02 | 20 |
| D | 1.7 | 65.7 | 61 | 7.4 | 0.9 | 0.02 | 40 |