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Table 2 Substrate composition and operational parameters of the full-scale processes included in the study

From: Identifying targets for increased biogas production through chemical and organic matter characterization of digestate from full-scale biogas plants: what remains and why?

Plant Substrate composition
(% of ingoing volume)
OLR
(ton VS/m3·day)
HRT
(days)
T
(°C)
Sampling points
FW1 Food waste (60%), slaughterhouse waste (25%), industrial waste (15%)     Substrate mixture
4.2 35 42 Digester
  20 41 Post-digester
FW2 Food waste, vegetables, moulded food packages, slaughterhouse waste, food industry waste, pig manure, grease separator sludge1     Substrate mixture
3.0 25–35 37 Digester
  5 37 Post-digester
FW3 Organic fraction of municipal household waste (100%)     Substrate mixture
3.8 27 38 Digester
  7 36 Post-digester
FW-TD Organic fraction of municipal household waste (98%), garden waste (2%)     Substrate mixture
4.7 27 55 Digester
AW1 Starch slurry (80%), cereals (18%), forage and corn silage (2%)     Starch slurry
    Cereals
    Corn silage
5.8 55 38 Digester
  40 38 Post-digester
AW2 Crop silage (46%), corn silage (26%), sugar beets (16%), cereals (12%)     Substrate mixture
3.1 40 38 Digester
  45 38 Post-digester
AWM Pig manure (52%), grease sludge (16%), cow manure (12%), agricultural residues (12%), chicken manure (3%), deep litter (3%), slaughterhouse waste (2%)     Manure slurry + grease
    Remaining fractions (see left)
3.4 55 38 Digester A
3.4 55 38 Digester B
WWTP1 Primary and activated sewage sludge (98%), grease separator sludge (2%)     Substrate mixture
2.5 20 38 Digester
WWTP2-A
WWTP2-B
Different substrate fractions for digester A and B, see below:     Primary sludge
    Activated sewage sludge
    Grease separator sludge
Primary (80%) and activated (20%) sewage sludge 1.5 17 37 Digester A
Primary (80%) and activated (12%) sewage sludge, grease separator sludge (8%) 1.8 15 37 Digester B
  1. 1 Volume fractions of the substrate were not provided by the biogas plant
  2. Several plants received a combination of substrates and were designated as FW/AW/WWTP relative to the main substrate fraction. FW food waste, FW-TD thermophilic dry digestion of food waste, AW plant-based agricultural waste, AWM agricultural waste + manure, WWTP wastewater treatment plant, OLR organic loading rate (ton VS/m3 day), HRT hydraulic retention time (days), T temperature (°C)