Table 1.
Operational periods, and associated parameters, of R1+2.
| Period | P1 | P2 | P3 | P4 | P5 | |
|---|---|---|---|---|---|---|
| Days | 0–95 | 96–299 | 300–457 | 458–604 | 605–742 | |
| Bioreactor temperaturea | 15 | 15 | 15 | 15 | 15 | |
| Influent CODb | 5 | 5 | 5 | 5 | 5 | |
| Upflow velocityc | 5 | 5 | 5 | 5 | 5 | |
| HRT (h) | 36 | 24 | 24 | 24 | 24 | |
| OLRd | 0.288 | 0.433 | 0.433 | 0.433 | 0.433 | |
| OLRe | 3.32 | 5 | 5 | 5 | 5 | |
| VLRf | 0.66 | 1.0 | 1.0 | 1.0 | 1.0 | |
| % CH4 in Biogas | R1 | 52.45 (0.65) | 62 (0.1) | 64 (0.1) | 63.2 (0.1) | 64.5 (0.3) |
| R2 | 61.5 (0.5) | 64 (0.1) | 60 (0.15) | 62.1 (0.15) | 53.7 (0.5) | |
| % COD Removal | R1 | 76.42 (2.13) | 92.92 (0.5) | 94.15 (0.4) | 96.15 (0.3) | 93.85 (0.8) |
| R2 | 83.52 (1.62) | 94.04 (0.46) | 89.61 (0.74) | 87.71 (0.52) | 91.15 (0.7) | |
| Influent SO2−g4 | R1 | – | – | – | – | – |
| Influent SO2−g4 | R2 | – | – | 0.625 | 1.66 | 10 |
| Influent SO2−h4 | R2 | – | – | 0.0065 | 0.017 | 0.1 |
| Effluent SO2−i4 | R1 | – | – | – | – | – |
| Effluent SO2−i4 | R2 | – | – | 10.37 (1.95) | 291.52 (27.0) | 3776.29 (126.24) |
| Effluent H2Si | R1 | – | – | – | – | – |
| Effluent H2Sh | R2 | – | – | 0.69 (0.18) | 176.27 (13.44) | 116.49 (4.86) |
| SO4 Ratei | R2 | 46.71 (0.02) | 201.56 (0.49) | 862.06 (2.21) | ||
| H2S Ratek | R2 | – | – | 0.052 (0.001) | 25.96 (0.25) | 16.04 (0.09) |
Standard errors (standard deviation/vn, where n is the number of days in a given period) are presented in parentheses.
a
Degrees Celsius.
b
g l−1.
c
m h−1.
d
OLR expressed as kg COD kg (VSS)−1 d−1.
e
OLR expressed as kg COD m−3 d−1.
f
m3wastewater m−3reactor d−1.
g
g l−1.
h
M l−1.
i
mg l−1.
j
Average g sulfate reduced Kg (VSS)−1 d−1.
k
Average g sulfide produced kg (VSS)−1 d−1.