41 research outputs found
Biological treatment of the organic fibre from the autoclaving of municipal solid wastes : preliminary results
Commingled municipal solid waste (MSW) was autoclaved in the presence of saturated steam for 30 min at 145 °C and 600 kPa. The organic fibre fraction from the autoclaved resulting material was examined for biodegradability. Aerobic and anaerobic tests were carried out to characterise the fibre in terms of biodegradation potential, which was moderate (biogas production potential of 251 ± 22 l [biogas] kg⁻¹ [total solids (TS)] and dynamic respiration index (DRI) of 1575 ± 116 mg [O2] kg⁻¹ [TS] h⁻¹). Manual and chemical characterisations were also performed to organic fibre. Following this characterisation, a laboratory-scale thermophilic anaerobic digestion process and a pilot-scale composting process were carried out to determine the possibilities of these biological treatments. In the anaerobic digestion process the biogas yield values obtained were within 0.15-0.21 m³ [biogas] kg⁻¹ [volatile solids (VS)] with an organic loading rate (OLR) of 3 kg [VS] m⁻³ d⁻¹. However, it was difficult to reach the steady state in the anaerobic thermophilic process for the different organic loads tested. Further experiments are necessary to determine the optimal biogas production and performance under these conditions. The composting process performed correctly and the final material was stable (DRI of 504 ± 74 mg [O2] kg⁻¹ [TS] h⁻¹) and with good properties for its application to soil regarding heavy metal contents that corresponding to class B compost, with the exception of some metals that corresponded to class A
Estudi de les emissions gasoses del compostatge de fangs
En el tractament biològic de les aigües residuals urbanes es generen grans quantitats de fangs rics en matèria orgànica i determinats elements químics, composició que els fa un residu ideal per ser valoritzat mitjançant compostatge. Ara bé, les instal·lacions necessàries per realitzar aquest procés generen rebuig social, sovint vinculat a les males olors. Aquest article ha estudiat les emissions durant el procés de compostatge de dos tipus de fangs produïts en plantes depuradores. Els resultats obtinguts es poden utilitzar en diversos àmbits.En el tratamiento biológico de las aguas residuales urbanas se generan cantidades de lodos ricos en materia orgánica y determinados elementos q composición que los hace un residuo ideal para ser valorizado mediante com Ahora bien, las instalaciones necesarias para realizar este proceso generan social, a menudo vinculado a los malos olores. Este artículo ha estudi emisiones durante el proceso de compostaje de dos tipos de lodos produ plantas depuradoras. Los resultados obtenidos se pueden utilizar en ámbitos.Biological treatment of municipal waste water generates large amounts of slu rich in organic matter and certain chemicals. This composition rends sludge ideal waste to be valorised through composting. However, the compos facilities generate social rejection, often due to odour pollution. This article studied gaseous emissions during the composting process of two types of slu produced in wastewater treatment plants. The results obtained can be applie various fields
Gaseous emissions in municipal wastes composting : effect of the bulking agent
In this study, the emissions of volatile organic compounds (VOC), CH₄, N₂O and NH₃ during composting non-source selected MSW, source selected organic fraction of municipal solid wastes (OFMSW) with wood chips as bulking agent (OF_wood) and source selected OFMSW with polyethylene (PE) tube as bulking agent (OF_tube) and the effect of bulking agent on these emissions have been systematically studied. Emission factors are provided (in kg compound Mg⁻¹ dry matter): OF_tube (CH₄: 0.0185 ± 0.004; N₂O: 0.0211 ± 0.005; NH₃: 0.612 ± 0.269; VOC: 0.688 ± 0.082) and MSW (CH₄: 0.0549 ± 0.0171; N₂O: 0.032 ± 0.015; NH₃: 1.00 ± 0.20; VOC: 1.05 ± 0.18) present lower values than OF_wood (CH₄: 1.27 ± 0.09; N₂O: 0.021 ± 0.006; NH₃: 4.34 ± 2.79; VOC: 0.989 ± 0.249). A detailed composition of VOC is also presented. Terpenes were the main emitted VOC family in all the wastes studied. Higher emissions of alpha and beta pinene were found during OF_wood composting processes
A systematic study of the gaseous emissions from biosolids composting : raw sludge versus anaerobically digested sludge
Volatile organic compound (VOC) and ammonia, that contribute to odor pollution, and methane and nitrous oxide, with an important greenhouse effect, are compounds present in gaseous emission from waste treatment installations, including composting plants. In this work, gaseous emissions from the composting of raw (RS) and anaerobically digested sludge (ADS) have been investigated and compared at pilot scale aiming to provide emission factors and to identify the different VOC families present. CH₄ and N₂O emissions were higher in ADS composting (0.73 and 0.55 kg Mg⁻¹ sludge, respectively) than in RS composting (0.01 kg Mg⁻¹ sludge for both CH₄ and N₂O). NH₃ and VOCs emitted were higher during the RS composting process (19.37 and 0.21 kg Mg⁻¹ sludge, respectively) than in ADS composting (0.16 and 0.04 kg Mg⁻¹ sludge). Significant differences were found in the VOC compositions emitted in ADS and RS composting, being more diverse in RS than ADS composting
A systematic study of the gaseous emissions from biosolids composting : raw sludge versus anaerobically digested sludge
Volatile organic compound (VOC) and ammonia, that contribute to odor pollution, and methane and nitrous oxide, with an important greenhouse effect, are compounds present in gaseous emission from waste treatment installations, including composting plants. In this work, gaseous emissions from the composting of raw (RS) and anaerobically digested sludge (ADS) have been investigated and compared at pilot scale aiming to provide emission factors and to identify the different VOC families present. CH₄ and N₂O emissions were higher in ADS composting (0.73 and 0.55 kg Mg⁻¹ sludge, respectively) than in RS composting (0.01 kg Mg⁻¹ sludge for both CH₄ and N₂O). NH₃ and VOCs emitted were higher during the RS composting process (19.37 and 0.21 kg Mg⁻¹ sludge, respectively) than in ADS composting (0.16 and 0.04 kg Mg⁻¹ sludge). Significant differences were found in the VOC compositions emitted in ADS and RS composting, being more diverse in RS than ADS composting
VOC emissions from the composting of the organic fraction of municipal solid waste using standard and advanced aeration strategies
Background: the emission of volatile organic compounds (VOC) during the composting process is mainly responsible for the odors generated in these types of waste treatment plants. In this work, VOC emissions from the source-separated organic fraction of municipal solid waste (OFMSW) composting process have been investigated in 50 L pilot reactors operating under different aeration control strategies during the active decomposition stage. - Results: the VOC emissions from traditional aeration control options such as oxygen feedback control or cyclic on-off aeration have been compared with VOC emissions under an oxygen uptake rate (OUR) control strategy. Total VOC emission (mg C m⁻³) and VOC composition (%) have been determined during the first active decomposition stage of composting. Study of VOC composition indicated a high presence of terpenes. Carcinogenic compounds, such as furans, have occasionally been found at very low concentration. Results indicate some differences in VOC composition according to the aeration strategy used. - Conclusions: the evolution of total VOC emissions was relatively similar, being high in the first days of the process. However, the results obtained show some differences in VOC composition depending on the aeration strategy used. The OUR controller provided a more steady emissions profile, which will help the performance of further gas treatment operations, specially biological systems
Gaseous emissions during the solid state fermentation of different wastes for enzyme production at pilot scale
The emissions of volatile organic compounds (VOC), CH₄, N₂O and NH₃ during the solid state fermentation process of some selected wastes to obtain different enzymes have been determined at pilot scale. Orange peel + compost (OP), hair wastes + raw sludge (HW) and winterization residue + raw sludge (WR) have been processed in duplicate in 50 L reactors to provide emission factors and to identify the different VOC families present in exhaust gaseous emissions. Ammonia emission from HW fermentation (3.2 ± 0.5 kg Mg⁻¹ dry matter) and VOC emission during OP processes (18 ± 6 kg Mg⁻¹ dry matter) should be considered in an industrial application of these processes. Terpenes have been the most emitted VOC family during all the processes although the emission of sulphide molecules during HW SSF is notable. The most emitted compound was dimethyl disulfide in HW and WR processes, and limonene in the SSF of OP
Co-composting: An Opportunity to Produce Compost with Designated Tailor-Made Properties
AbstractCo-composting is a technique that allows the aerobic degradation of organic waste mixtures, primarily aiming at obtaining compost that can be used as fertiliser or soil amendment. As compared to the typical composting activity, the main difference is not merely the use of more than one feedstock to start and sustain the biodegradation process, but also the possibility of combining various kinds of waste to obtain 'tailored' products with designed properties, or to reclaim and valorise natural resources, such as degraded soils or polluted soils and sediments. Set up of appropriate co-composting protocols can be a way to optimise the management of waste produced by different sectors of agriculture and industry and also from human settlements. Different formulations can not only optimise the biodegradation process through the adjustment of nutrient ratios, but also lead to the formation of products with innovative properties. Moreover, co-composting can be a technique of choice for the reclamation of soils degraded by intensive agriculture or contaminated soils and sediments. In fact, an appropriate mix of organic waste and soils can restore the soil structure and induce fertility in nutrient-depleted soils, and also remediate polluted soils and sediments through degradation of organic pollutants and stabilisation of heavy metals. While the selection of different mixes of organic waste may lead to the design of composts with specific properties and the potential valorisation of selected waste materials, there are still several factors that hamper the development of co-composting platforms, mainly insufficient knowledge of some chemical and microbiological processes, but also some legislative aspects. This chapter illustrates the progress achieved in co-composting technology worldwide, some key legislative aspects related to the co-composting process, the main scientific and technical aspects that deserve research attention to further develop co-composting technology, and successful applications of co-composting for the reclamation of soils and sediments, allowing their use for cultivation or as growing media in plant nurseries. A specific case study of the production of fertile plant-growing media from sediment co-composting with green waste is also illustrated
Estudi de les emissions gasoses en processos biològics de valorització material de residus sòlids. Caracterització de l’emissió de compostos orgànics volàtils
El
creixement
econòmic
mundial
viscut
durant
la
segona
meitat
del
segle
XX,
ha
provocat
un
gran
increment
en
la
generació
de
residus.
És
per
això
que
les
darreres
polítiques
europees
defineixen
l’objectiu
de
tractar
un
mínim
del
50%
dels
residus
municipals
mitjançant
el
reciclatge
abans
de
l’any
2020.
En
el
cas
dels
residus
orgànics
biodegradables,
aquest
reciclatge
o
valorització
s’aconsegueix
principalment
mitjançant
processos
biològics
com
el
compostatge
i
la
digestió
anaeròbia.
L’actual
escenari
europeu
pel
que
fa
a
instal·lacions
de
valorització
de
residus
orgànics
i
l’aparició
d’aquestes
noves
polítiques,
fan
pensar
en
una
futura
proliferació
d’instal·lacions,
entre
les
quals
hi
haurà
una
gran
quantitat
de
plantes
de
compostatge,
que
permetin
assolir
l’objectiu
fixat.
Davant
aquesta
futura
proliferació
d’instal·lacions
de
compostatge
(i
de
tractament
de
residus
en
general)
caldrà
tenir
en
compte
els
impactes
ambientals
associats
al
propi
procés,
entre
els
quals
destaquen
les
emissions
gasoses
derivades
de
la
degradació
biològica
de
la
matèria
orgànica.
Entre
els
compostos
gasosos
presents
en
aquestes
emissions
cal
destacar
el
metà,
l’amoníac,
l’òxid
nitrós
i
els
compostos
orgànics
volàtils
(COV).
D’aquests
compostos,
el
metà
i
l’òxid
nitrós
són
considerats
gasos
d’efecte
hivernacle,
mentre
que
l’amoníac
i
els
COV
són
els
principals
causants
de
les
males
olors
associades
a
aquestes
instal·lacions
de
tractament.
El
Grup
de
Recerca
en
Compostatge
(GICOM),
en
el
que
s’ha
desenvolupat
aquesta
tesi,
té
una
àmplia
experiència
en
l’estudi
del
compostatge,
ja
sigui
a
nivell
del
propi
procés,
del
seu
control
o
de
les
seves
emissions
a
escala
industrial.
Tanmateix,
en
els
darrers
anys
s’ha
iniciat
una
nova
línia
de
recerca
dins
el
grup
per
explorar
el
potencial
de
la
fermentació
en
estat
sòlid
(SSF)
com
una
altra
via
de
valorització
material
de
residus,
habitualment
industrials,
amb
l’objectiu
d’obtenir
productes
de
valor
afegit
(enzims,
biopesticides,
biosurfactants,
etc.)
a
partir
de
residus.
Així
doncs,
en
aquesta
tesi
s’ha
volgut
aprofitar
l’àmplia
experiència
en
compostatge
del
grup
de
recerca
per
tal
d’aprofundir
en
el
coneixement
de
les
emissions
gasoses
derivades
dels
processos
biològics
de
valorització
material
de
residus
sòlids
orgànics,
determinant
els
factors
d’emissió
per
COV,
CH4,
N2O,
NH3
i
caracteritzant,
per
identificació
i
quantificació,
els
COV
emesos
durant
el
tractament
de
diferents
residus
a
escala
pilot.
Per
assolir
aquest
objectiu
genèric,
s’ha
posat
en
marxa
un
mètode
d’identificació
i
quantificació
dels
COV
mitjançant
la
cromatografia
de
gasos
acoblada
a
l’espectrometria
de
masses
i
s’han
estudiat
les
emissions
de
COV
d’un
procés
de
compostatge
convencional
sota
diferents
estratègies
d’aeració
del
procés.
D’aquesta
manera
es
defineixen
dos
aspectes
metodològics
que
permetran
continuar
la
recerca
d’aquesta
tesi,
l’estratègia
de
procés,
per
una
banda,
i
la
metodologia
de
presa
de
mostra
i
anàlisi
dels
gasos
per
l’altra.
A
partir
d’aquesta
base
metodològica
es
procedeix
a
analitzar,
quantitativament
i
qualitativa,
les
emissions
derivades
del
procés
de
compostatge
de
residus
d’origen
urbà
com
poden
ser
els
fangs
d’EDAR,
frescos
i
digerits,
o
bé
la
Fracció
Orgànica
dels
Residus
Municipals
(FORM).
En
aquest
darrer
cas,
comparant
el
desenvolupament
del
procés
de
compostatge
de
la
FORM
separada
selectivament
i
dels
Residus
Sòlids
Urbans
no
separats
selectivament
amb
les
emissions
que
se’n
deriven,
així
com
determinant
la
contribució
de
la
fusta
utilitzada
com
a
agent
estructurant
a
les
emissions
del
procés.
Finalment,
s’han
estudiat
també
les
emissions
associades
a
la
valorització
material
de
residus
més
específics
com
són
la
pela
de
taronja,
el
residu
de
pèl
i
el
residu
de
winterització
amb
l’objectiu
de
produir
diferents
enzims
a
través
de
la
SSF.World
economic
growth
during
the
second
half
of
the
XX
century
has
caused
a
great
increase
in
waste
generation.
This
fact
has
been
reflected
in
European
policies
which
define
the
objective
of
recycling,
at
least,
50%
of
municipal
waste
before
2020.
In
the
case
of
biodegradable
organic
wastes,
this
purpose
can
be
achieved
mainly
through
biological
treatments
such
as
composting
and
anaerobic
digestion.
In
order
to
achieve
the
proposed
target,
the
current
European
scenario
in
terms
of
organic
waste
valorisation
facilities
and
the
emergence
of
these
new
policies,
suggest
a
future
proliferation
of
biological
treatment
facilities,
among
which
there
will
be
a
lot
of
composting
plants.
Given
this
upcoming
proliferation
of
composting
facilities
(and
waste
treatment
plants
in
general),
the
environmental
impacts
associated
with
the
composting
process
must
be
taken
into
account,
paying
special
attention
to
gaseous
emissions
resulting
from
biological
degradation
of
organic
matter.
The
main
contaminants
in
these
emissions
are
methane,
ammonia,
nitrous
oxide
and
volatile
organic
compounds
(VOC).
Methane
and
nitrous
oxide
are
considered
greenhouse
gases,
while
ammonia
and
VOC
are
the
main
cause
of
odours
associated
with
these
treatment
facilities.
The
Composting
Research
Group
(GICOM),
where
this
thesis
has
been
developed,
has
a
wide
research
experience
in
composting,
either
studying
the
biological
process
itself,
process
control
or
process
gaseous
emissions
at
full
scale.
Besides,
in
recent
years
GICOM
has
started
a
new
research
line
exploring
the
potentiality
of
solid
state
fermentation
(SSF)
as
another
way
to
valorise
organic
wastes,
commonly
from
industrial
processes,
with
the
aim
of
obtaining
value-‐added
products
(enzymes,
biopesticides,
biosurfactants,
etc.).
In
this
thesis
the
research
experience
of
the
group
has
been
used
to
analyse
in
depth
the
gaseous
emissions
from
biological
valorisation
processes
of
solid
organic
wastes,
determining
emission
factors
for
VOC,
CH4,
N2O,
NH3
and
characterizing,
by
identification
and
quantification,
VOC
emissions
during
the
treatment
of
different
wastes
at
pilot
scale.
To
achieve
this
overall
objective,
a
methodology
to
identify
and
quantify
VOC
by
gas
chromatography
coupled
to
mass
spectrometry
has
been
set-‐up.
Also,
VOC
emissions
during
a
conventional
composting
process
under
different
aeration
strategies
have
been
studied.
Thus,
two
methodological
issues
essential
for
the
development
of
this
thesis
have
been
defined
on
one
hand,
the
process
strategy
and
on
the
other
hand,
the
gaseous
emission
sampling
methodology
and
analysis.
From
this
methodological
basis,
gaseous
emissions
from
the
composting
process
of
urban
wastes,
such
as
WWTP
sludge,
either
raw
or
digested,
and
also
de
Organic
Fraction
of
Municipal
Solid
Wastes
(OFMSW)
have
been
analysed,
quantitatively
and
qualitatively.
The
OFMSW
composting
process
and
its
emissions
have
been
compared
to
non-‐source
selected
Municipal
Solid
Wastes
(MSW).
Also,
the
contribution
of
wood
chips
(used
as
bulking
agent)
to
the
composting
process
emissions
has
been
determined.
Finally,
the
emissions
associated
to
the
material
valorisation
of
specific
wastes
such
as
orange
peel,
hair
wastes
and
residue
of
winterization
in
order
to
produce
various
enzymes
through
SSF,
have
also
been
studied.
In
addition
to
the
scientific
interest
of
this
thesis,
which
is
reflected
by
the
papers
published
in
high
impact
journals
in
the
field
of
Environmental
Engineering,
it
increases
the
research
group
know-‐how
on
the
treatment
of
different
wastes
at
pilot
scale.
The
definition
of
a
methodology
for
gaseous
emissions
determination
that
can
be
implemented
in
future
experiments
performed
in
the
GICOM
pilot
plant
is
also
relevant.
This
methodology
will
allow
the
quantification
of
CH4,
N2O
and
NH3,
the
qualitatively
determination
of
VOC
emissions
and
the
quantification
of
the
most
commonly
found
compounds.
This
last
point
will
permit
to
include
data
on
the
emissions
of
the
material
valorisation
processes
carried
out
in
the
research
group
pilot
plant,
reporting
valuable
information
on
the
environmental
impact
of
the
process
also
useful
in
the
design
of
the
required
emissions
equipment