Table 4 (continued)
Feedstock Reactor
Digesting
temperature
(°C)
Inoculum/seed
sludge source
Manipulated
factors
Operating
conditions
Findings
References
OLR
HRT
POME
Combination
of high rate
anaerobic
reactors (AHR
+ABF and
AHR+ADF)
36
−
Type of
reactors, reactor
configuration,
OLR
0.91–
23 kg
COD
m
−3
d
−1
0.7–2.4
days
• COD removal of 93.5% was
achieved
• Having secondary reactor
enhances COD removal
efficiency and performance
stability
• Production of biogas of up to
110 L/d
• Methane content of 59.5–
78.2%
Choi et al.
(2013)
POME
50 L
bioreactor
30–35
POME sludge
from methane
recovery test
plant
Reactor
configuration,
OLR
0.5–
6.0 kg
COD
m
−3
d
−1
79–92
days
• Mix and settle system were
preferred compared to
semi-continuous mode as it
improves the biomass
retention
• Biogas production at OLR of
6.0 kg COD m
−3 d
−1 is 2.42
m
3
/m
3 of reactor/day (0.992
m
3
methane/m
3 of reactor/day)
Basri et al.
(2010)
EFB
500 ml batch
reactor
37
–
Feedstock to
inoculum (F: I)
ratio, raw
materials
–
–
• Increasing F: I ratio reduced
methane generation
• F:I ratio of 2:1 produced the
highest methane yield for
SS-AD of EFB (144 mL CH 4 /
g-VS) followed by PPF (140
mL CH 4 /g-VS) and DC (130
mL CH 4 /g-VS)
• Methane production recorded
are EFB (55 m
3 CH 4 /ton),
PPF(47 m
3 CH 4 /ton) and DC
(41 m
3 CH 4 /ton)
Chaikitkaew
et al (2015)
PPF
DC
EFB + DC 500 ml of
serum bottle
35–55
-
EFB: DC ratio
–
–
• Synergic effect at EFB: DC
ratio of 1: 1 only, while other
ratios showed antagonistic
effect
• Thermophilic temperature
enhanced methane production
by 5 times as compared to
mesophilic temperature
Tepsour
et al. (2019)
POME +
EFB
250 ml serum
bottle
35
Anaerobic
sludge
EFB: POME
ratio
1.8 g
VS/L
25 days • Addition of EFB improved
the overall production of
methane
• Production of methane from
EFB: POME ratio of
0.25: 0.31 is 1.2 times higher
than AD of POME alone
Kim et al.
(2013)
POME +
SCS,
POME
+SBS,
EFB +
SCS, EFB
+ SBS
500 ml serum
bottles
35
Mesophilic
methane
sludge
Feedstock,
co-substrate,
co-digestion
ratio
–
–
• Co-digestion of POME and
EFB with sewage sludge
increased methane production
– POME: sewage chemical
sludge at 99: 1 gave 456 mL
CH 4 g
−1 VS methane yield
Suksong
et al. (2017)
(continued)
Palm Oil Industry—Processes, By-Product ...
135
Feedstock Reactor
Digesting
temperature
(°C)
Inoculum/seed
sludge source
Manipulated
factors
Operating
conditions
Findings
References
OLR
HRT
POME
Combination
of high rate
anaerobic
reactors (AHR
+ABF and
AHR+ADF)
36
−
Type of
reactors, reactor
configuration,
OLR
0.91–
23 kg
COD
m
−3
d
−1
0.7–2.4
days
• COD removal of 93.5% was
achieved
• Having secondary reactor
enhances COD removal
efficiency and performance
stability
• Production of biogas of up to
110 L/d
• Methane content of 59.5–
78.2%
Choi et al.
(2013)
POME
50 L
bioreactor
30–35
POME sludge
from methane
recovery test
plant
Reactor
configuration,
OLR
0.5–
6.0 kg
COD
m
−3
d
−1
79–92
days
• Mix and settle system were
preferred compared to
semi-continuous mode as it
improves the biomass
retention
• Biogas production at OLR of
6.0 kg COD m
−3 d
−1 is 2.42
m
3
/m
3 of reactor/day (0.992
m
3
methane/m
3 of reactor/day)
Basri et al.
(2010)
EFB
500 ml batch
reactor
37
–
Feedstock to
inoculum (F: I)
ratio, raw
materials
–
–
• Increasing F: I ratio reduced
methane generation
• F:I ratio of 2:1 produced the
highest methane yield for
SS-AD of EFB (144 mL CH 4 /
g-VS) followed by PPF (140
mL CH 4 /g-VS) and DC (130
mL CH 4 /g-VS)
• Methane production recorded
are EFB (55 m
3 CH 4 /ton),
PPF(47 m
3 CH 4 /ton) and DC
(41 m
3 CH 4 /ton)
Chaikitkaew
et al (2015)
PPF
DC
EFB + DC 500 ml of
serum bottle
35–55
-
EFB: DC ratio
–
–
• Synergic effect at EFB: DC
ratio of 1: 1 only, while other
ratios showed antagonistic
effect
• Thermophilic temperature
enhanced methane production
by 5 times as compared to
mesophilic temperature
Tepsour
et al. (2019)
POME +
EFB
250 ml serum
bottle
35
Anaerobic
sludge
EFB: POME
ratio
1.8 g
VS/L
25 days • Addition of EFB improved
the overall production of
methane
• Production of methane from
EFB: POME ratio of
0.25: 0.31 is 1.2 times higher
than AD of POME alone
Kim et al.
(2013)
POME +
SCS,
POME
+SBS,
EFB +
SCS, EFB
+ SBS
500 ml serum
bottles
35
Mesophilic
methane
sludge
Feedstock,
co-substrate,
co-digestion
ratio
–
–
• Co-digestion of POME and
EFB with sewage sludge
increased methane production
– POME: sewage chemical
sludge at 99: 1 gave 456 mL
CH 4 g
−1 VS methane yield
Suksong
et al. (2017)
(continued)
Palm Oil Industry—Processes, By-Product ...
135