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Table 5 Operational variables for the AD experiments in UASB reactors

From: Reduced use of phosphorus and water in sequential dark fermentation and anaerobic digestion of wheat straw and the application of ensiled steam-pretreated lucerne as a macronutrient provider in anaerobic digestion

  CH-1, lower OLR CH-DFE, lower OLR CH-DFE, higher OLR
OLR, COD (g/L/day) 5.4 ± 0.5 5.4 ± 0.5 8.5 ± 0.2
HRT (day) 5.9 ± 0.3 5.5 ± 0.5 3.8 ± 1.3
Duration (day) 17.0 ± 2.0 19 ± 0 13.3 ± 4
Methane yield per COD fed, (mL/g) 268 ± 7 262 ± 17 265 ± 15
Methane yield per COD fed, % of maximum 76.7 ± 2.2 74.8 ± 4.7 75.6 ± 4.3
Effluent COD (g/L)a 3.6b 3.8 ± 0.3 5.1 ± 0.6
COD removal (%)a 89.2b 88.7 ± 5.9 84.8 ± 1.9
Effluent pHa 6.84b 7.22 ± 0.02 7.20 ± 0.03
Effluent acetic acida (g/L) 0.11b 0.21 ± 0.07 0.23 ± 0.13
Effluent propionic acida (g/L) 0.11b 0.05 ± 0.07 0.27 ± 0.14
Effluent fatty acids, totala, c (g/L) 0.22b 0.26 ± 0.14 0.60 ± 0.26
Partial alkalinitya in effluent (g/L) 1.2b 2.5 ± 0.0 1.8 ± 0.2
Total alkalinitya in effluent (g/L) 1.3b 3.0 ± 0.1 2.7 ± 0.0
  1. COD chemical oxygen demand, HRT hydraulic retention time, OLR organic loading rate
  2. aAfter running the experiment for a duration corresponding to three times the HRT
  3. bValue for one reactor, data missing for the other
  4. cVolatile fatty acids with 1–5 carbons and lactic acid
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