Table 4 Summary of the operational condition of the anaerobic digestion of palm oil mill by-products
Feedstock Reactor
Digesting
temperature
(°C)
Inoculum/seed
sludge source
Manipulated
factors
Operating
conditions
Findings
References
OLR
HRT
POME
250 mL batch
reactor
55
Anaerobic seed
sludge from
the oil mill
Solid: liquid
ratio
–
–
• Higher solid loadings reduce
AD performance
• TSS removal (%), COD and
BOD decrease as solid
content increases
• 40S: 60 L is the best solid
loading, producing 1431
±17 mL biogas and 48.89
±1.12 CH 4 /g COD
Khadaroo
et al. (2020)
EFB
500 mL of
serum bottle
35–55
Anaerobic
sludge from
commercial
biogas
production of
POME
Addition of oil
palm ash
(OPA), raw
materials,
substrate:
inoculum (S: I)
ratio
–
–
• AD of EFB produces higher
methane yield compared to
DC
• Addition of OPA reduces
methane production
• At 3: 1 ratio, methane yield
for AD of EFB is 353.0
mL-CH 4 /g-VS without the
addition of OPA and AD of
DC with the addition of 10%
OPA is 101.5 mL-CH 4 /g-VS
• Liquid anaerobic digestate can
be an effective inoculum for
AD of EFB and DC
Tepsour
et al. (2019)
Decanter
Cake
(DC)
POME
5.81 L CSTR
55
Anaerobic seed
sludge
obtained from
water quality
control plant
Configuration
of CSTR,
POME: water
ratio, OLR
2.0–
19.0 g
COD
L
−1
d
−1
3.3 days • Modified CSTR with deflector
captured higher amount of
palm fibres compared to
ordinary CSTR
• Average methane yield: 0.27
L/g COD
• Biogas production of 6.23 L/L
d
• COD removal efficiency of
82%
Khemkhao
et al. (2015)
POME
Anaerobic
hybrid reactor
(UASB with
AF)
37–55
Mesophilic
seed slurry
from a brewery
Temperature,
OLR
2.0–
15.0
kg
COD
m
−3
d
−1
5.8–6.2
days
• OLR of 15 kg [COD] m
−3 d
−1
gave 90–95% total COD
removal
• Thermophilic temperature
gave better COD removal and
biogas production (20.0 L/d)
compared to mesophilic
temperature (13.5 L/d)
Jeong et al.
(2014)
POME
UASB-HCPB
55
Thermophilic
mixed culture
Start-up
strategy, OLR
4.28–
27.65
g COD
L
−1
d
−1
2–5
days
• After 36-day treatment:
– COD removal: 88%
– BOD removal: 90%
– Methane (%) in biogas: 52%
at OLR of 28.12 g L
−1 d
−1
• More than 90% of BOD and
COD removal was achieved
and approximately 60% of
methane was achieved at
– HRT: 2 days
– OLR: 27.65 g L
−1 d
−1
– MLVSS concentration: 14.7 g
L
−1
Poh and
Chong
(2014)
(continued)
134
R. Shamsuddin et al.
Feedstock Reactor
Digesting
temperature
(°C)
Inoculum/seed
sludge source
Manipulated
factors
Operating
conditions
Findings
References
OLR
HRT
POME
250 mL batch
reactor
55
Anaerobic seed
sludge from
the oil mill
Solid: liquid
ratio
–
–
• Higher solid loadings reduce
AD performance
• TSS removal (%), COD and
BOD decrease as solid
content increases
• 40S: 60 L is the best solid
loading, producing 1431
±17 mL biogas and 48.89
±1.12 CH 4 /g COD
Khadaroo
et al. (2020)
EFB
500 mL of
serum bottle
35–55
Anaerobic
sludge from
commercial
biogas
production of
POME
Addition of oil
palm ash
(OPA), raw
materials,
substrate:
inoculum (S: I)
ratio
–
–
• AD of EFB produces higher
methane yield compared to
DC
• Addition of OPA reduces
methane production
• At 3: 1 ratio, methane yield
for AD of EFB is 353.0
mL-CH 4 /g-VS without the
addition of OPA and AD of
DC with the addition of 10%
OPA is 101.5 mL-CH 4 /g-VS
• Liquid anaerobic digestate can
be an effective inoculum for
AD of EFB and DC
Tepsour
et al. (2019)
Decanter
Cake
(DC)
POME
5.81 L CSTR
55
Anaerobic seed
sludge
obtained from
water quality
control plant
Configuration
of CSTR,
POME: water
ratio, OLR
2.0–
19.0 g
COD
L
−1
d
−1
3.3 days • Modified CSTR with deflector
captured higher amount of
palm fibres compared to
ordinary CSTR
• Average methane yield: 0.27
L/g COD
• Biogas production of 6.23 L/L
d
• COD removal efficiency of
82%
Khemkhao
et al. (2015)
POME
Anaerobic
hybrid reactor
(UASB with
AF)
37–55
Mesophilic
seed slurry
from a brewery
Temperature,
OLR
2.0–
15.0
kg
COD
m
−3
d
−1
5.8–6.2
days
• OLR of 15 kg [COD] m
−3 d
−1
gave 90–95% total COD
removal
• Thermophilic temperature
gave better COD removal and
biogas production (20.0 L/d)
compared to mesophilic
temperature (13.5 L/d)
Jeong et al.
(2014)
POME
UASB-HCPB
55
Thermophilic
mixed culture
Start-up
strategy, OLR
4.28–
27.65
g COD
L
−1
d
−1
2–5
days
• After 36-day treatment:
– COD removal: 88%
– BOD removal: 90%
– Methane (%) in biogas: 52%
at OLR of 28.12 g L
−1 d
−1
• More than 90% of BOD and
COD removal was achieved
and approximately 60% of
methane was achieved at
– HRT: 2 days
– OLR: 27.65 g L
−1 d
−1
– MLVSS concentration: 14.7 g
L
−1
Poh and
Chong
(2014)
(continued)
134
R. Shamsuddin et al.