bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 11, 2024
Abstract
Hydrothermal
liquefaction
(HTL)
can
convert
a
considerable
portion
of
the
carbon
in
complex
feedstocks
into
renewable
bio-oil,
but
it
also
generates
liquid
byproduct
(
i.e.
,
HTL
process
water)
that
retains
15
–
55%
from
feedstock.
Feeding
water
to
anaerobic
digestion
(AD)
is
promising
approach
for
maximizing
resource
recovery,
enabling
conversion
retained
biogas.
However,
various
toxic
and
poorly
biodegradable
compounds
make
its
treatment
with
AD
challenging.
Presently,
underlying
mechanisms
remain
often
unclear.
We
investigated
impact
two
different
food-waste
proxy
dog
food,
rich
proteins)
wheat
straw
(rich
lignocellulose)
on
trophic
groups
food
web
AD.
found
methanogens
rather
than
acidogens
were
inhibited
by
water.
Comparative
toxicity
biodegradability
analyses
showed
wheat-straw
had
higher
regardless
acetoclastic
water,
due
content
easily
degradable
aromatic
compounds.
Microaeration
enhanced
biodegradation
methane
yields
particularly
under
anoxic
conditions.
microaeration
was
ineffective
These
findings
highlight
importance
feedstock-specific
strategies
optimize
biogas
production
Bioresources and Bioprocessing,
Journal Year:
2024,
Volume and Issue:
11(1)
Published: May 7, 2024
Integrating
hydrothermal
treatment
processes
and
anaerobic
digestion
(AD)
is
promising
for
maximizing
resource
recovery
from
biomass
organic
waste.
The
process
water
generated
during
contains
high
concentrations
of
matter,
which
can
be
converted
into
biogas
using
AD.
However,
also
various
compounds
that
inhibit
the
AD
process.
Fingerprinting
these
inhibitors
identifying
suitable
mitigation
strategies
detoxification
methods
necessary
to
optimize
integration
two
technologies.
By
examining
existing
literature,
we
were
able
to:
(1)
compare
methane
yields
organics
removal
efficiency
water;
(2)
catalog
main
found
in
(3)
identify
recalcitrant
components
limiting
performance;
(4)
evaluate
approaches
detoxify
specific
degrade
components.
Common
are
acids
(at
concentrations),
total
ammonia
nitrogen
(TAN),
oxygenated
organics,
N-heterocyclic
compounds.
Feedstock
composition
primary
determinant
acid
TAN
formation
(carbohydrates-rich
protein-rich
feedstocks,
respectively).
In
contrast,
processing
conditions
(e.g.,
temperature,
pressure,
reaction
duration)
influence
extent
Struvite
precipitation
zeolite
adsorption
most
widely
used
eliminate
inhibition.
powdered
granular
activated
carbon
ozonation
preferred
remove
toxic
substances
before
treatment.
Currently,
effective
approach
reduce
toxicity
recalcitrance
N
O-heterocyclic
Microaeration
methods,
disrupt
microbiome
less
than
ozone,
might
more
practical
nitrifying
degrading
compounds,
but
further
research
this
area
necessary.
Water Research,
Journal Year:
2024,
Volume and Issue:
257, P. 121703 - 121703
Published: May 2, 2024
Hydrothermal
liquefaction
(HTL)
is
a
promising
thermo-chemical
technology
for
municipal
sludge
treatment
due
to
its
potential
biocrude
oil
recovery
and
minimizing
biosolids
management
costs.
However,
the
process
generates
high
volume
of
an
aqueous
byproduct
that
needs
be
treated
chemical
oxygen
demand
(COD)
various
organic
inorganic
compounds.
Although
phase
known
contain
recalcitrant
potentially
inhibitory
substances
may
affect
biological
treatment,
their
molecular
weight
distribution
(MwD)
impact
on
anaerobic
biodegradability
are
poorly
understood.
Ultrafiltration
(UF)
was
conducted
fractionate
HTL
into
different
(Mw)
fractions
using
300,
100,
10,
1
kDa
membranes.
Mesophilic
biochemical
methane
(BMP)
assays
were
assess
each
fraction,
first-order
model
used
calculate
degradation
kinetics
The
highest
percentage
organics
(65%)
found
in
Mw<1
range,
whereas
10>Mw>1
had
lowest
(8%).
There
no
significant
difference
cumulative
specific
produced
from
Mw
(p>0.05).
fraction
production
rate
(0.53
day−1),
unfiltered
(0.38
day−1).
UF
fractionation
increased
observed
only
55%
theoretical
value.
This
implies
45
%
COD
remains
undegraded
even
after
permeation
through
cut-off
membrane.
Therefore,
further
characterization
needed
compounds
with
weights
below
fully
understand
nature
digestion.
Furthermore,
pretreatments
utilizing
techniques
such
as
adsorption
advanced
oxidation
necessary
enhance
yields
fractions,
thereby
bringing
them
closer
yield.
