The biological treatment of landfill leachate using a simultaneous aerobic
and anaerobic (SAA) bio-reactor system
Zhiquan Yang, Shaoqi Zhou
*
School of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006, PR China
a r t i c l e
i n f o
Article history:
Received 1 February 2008
Received in revised form 18 April 2008
Accepted 18 April 2008
Available online 18 June 2008
Keywords:
Landfill leachate
COD
Ammonia
Organic pollutants
Toxins
Biological removal
a b s t r a c t
A set of simultaneous aerobic and anaerobic (SAA) bio-reactor system was used for the removal of organic
pollutants and ammonia in the landfill leachate generated from Datian Shan Landfill in Guangzhou,
China. The influent concentrations of COD and NH
þ
4
-N were 1000–3300 and 80–230 mg L
1
, respectively.
The average effluent concentrations of COD and NH
þ
4
-N were 131 and 7 mg L
1
, respectively. The concen-
trations of COD and NH
þ
4
-N had reached the Chinese second grade effluent standard (COD < 300 mg L
1
,
NH
þ
4
-N < 25 mg L
1
) for this kind of wastewater. Gas chromatogram–mass spectrum (GC/MS) analysis
was used to measure the organic pollutants in the landfill leachate. About 87 organics were detected
in this landfill leachate, and 16 of them belong to the list of environmental priority pollutants established
by the US Environmental Protection Agency. About 31 of the 87 organic pollutants were completely
removed by the SAA bio-reactor, the concentrations of further 14 organic pollutants were reduced by
more than 80%, and the removal efficiencies of the other 25 organic pollutants were over 50%.
Crown Copyright Ó 2008 Published by Elsevier Ltd. All rights reserved.
1. Introduction
Landfill leachate, a complicated form of waste water, is gener-
ated by excess rainwater percolating through layers of rubbish
(
). Surface water polluted by landfill leachate
in Germany is reported to have travelled 4 km from the landfill site
(
). Landfill leachate may also pollute groundwater
over a considerable depth (
). Many studies (
to and Gaspari, 2006; Koshy et al., 2007
) of landfill leachate toxicity
suggest that landfill leachate is a significant pollution source for
groundwater and surface water.
Among the pollutants in landfill leachate, the organic com-
pounds have significant effects on water quality.
investigated the organic pollutants in groundwater and sur-
face water at three landfills in north central Florida, and they con-
cluded that there was a lot of aromatic organic matter and many
undecomposed priority organic pollutants in the water. Many
studies of landfill leachate (
Benfenati et al., 2003; Seo et al.,
) have shown that there were various kinds of organic pollu-
tants in landfill leachate, such as alkenes, aromatic hydrocarbons,
acids, esters, alcohols, hydroxybenzene, aldehydes, ketones,
amides, etc. Many are listed as carcinogens or otherwise toxic.
The removal of organic components is a key step for the treatment
of landfill leachate.
Ammonia deserves special attention in the treatment of landfill
leachate, as it constitutes a critical long term pollutant (
), because waste water containing ammonia can be toxic to
aquatic life (
), can cause oxygen depletion
and eutrophication in receiving waters, and affect chlorine disin-
fection efficiency (
). Moreover, it may disrupt biologi-
cal units used for leachate treatment due to its toxicity. The
concentration of ammonia formed from nitrogen in wastes gener-
ally decreases only by leaching. Therefore, ammonia has been iden-
tified as the most significant component in leachate in the long
term (
).
Leachate components can be removed by various physicochem-
ical and biological processes. Coagulation and flocculation are rel-
atively simple techniques, but only lead to moderate removal of
COD (
). Ozonation might be a good technique to
treat landfill leachate, but high doses for complete degradation of
the pollutants would be required, rendering the process costly
(
). A combination of coagulation, absorption
and electrochemistry were used in large scale treatment of a land-
fill leachate, but the cost was so high that it was not considered
suitable (
et al., 2006; Castillo et al., 2007
) have stated that biological tech-
nology was one of the most cost-effective methods to treat landfill
leachate, especially for fresh leachate with a high BOD/COD ratio
(
Among various biological technologies, it is attractive to use
combined anaerobic and aerobic systems for the removal of COD
and ammonia, especially for the treatment of landfill leachate
0045-6535/$ - see front matter Crown Copyright Ó 2008 Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.chemosphere.2008.04.090
*
Corresponding author. Tel.: +86 20 87113533; fax: +86 20 85511266.
E-mail address:
(S. Zhou).
Chemosphere 72 (2008) 1751–1756
Contents lists available at
Chemosphere
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h e m o s p h e r e
(
). In conventional biological systems, anaerobic
and aerobic conditions are separated, or temporarily separated in
phases in sequencing batch reactors (SBR) (
).
A combination of aerobic and anaerobic degradation pathways in
a single reactor could be used to improve the overall degradation
efficiency (
). It is a good strategy because
both reductive and oxidative biotransformations might occur con-
comitantly to complete mineralization of highly substituted com-
pounds under micro-aeration. Under oxygen-limited condition,
simultaneous aerobic and anaerobic (SAA) occurs as a result of dis-
solved oxygen concentration gradients arising from diffusional
limitations (
).
In this research, a SAA bio-reactor (
Zhou et al., 1998; Zhou et al.,
) was used for the treatment of landfill leachate. The objective
was to evaluate the biological treatability of the leachate from mu-
nicipal landfill sites by observing removal capacity of COD, ammo-
nia and organic pollutants. The organic components were also
investigated by GC/MS.
2. Materials and methods
2.1. Experimental system
The leachate treatment employed comprised a regulating tank, a
sewage pump, an air compressor, the SAA bio-reactor and a desilter.
The flow process diagram is shown in
. The SAA bio-reactor was
made of stainless steel cylinder (60 cm internal diameter, 210 cm
height), with a volume of 600 L capacity. An inner cylinder (40 cm
internal diameter, 220 cm height) was located in the middle of the
reactor. On the top of the reactor was a 200 L gas-liquid-solid sepa-
rator. The regulating tank (2 1 1 m) and desilter (1 1 1 m)
were constructed by PVC. The landfill leachate used in this experi-
ment was taken from the leachate collection pool at Datian Shan.
It was pumped into the regulating tank, where it was diluted up
to 20% with tap water to achieve 1000 < COD < 3300 mg L
1
and
80 < NH
þ
4
-N < 230 mg L
1
, respectively.
The SAA bio-reactor was a combination of air lift reactor, flu-
idized bed and up-flow anaerobic sludge blanket. Inside the
reactor, the aerobic and anaerobic zones were established by
controlling aeration location, aeration capacity and reactor shape.
There were an inner cylinder and an outer cylinder in the bio-
reactor, as illustrated in
. The aerobic zone was formed in
the infrastructure of the inner cylinder, because air was supplied
from the bottom of the bio-reactor. The anaerobic zone was
formed in the outer cylinder due to the limitation of oxygen
content. Different aeration rates were obtained by controlling
the air flow rate using the air compressor. The reactor was oper-
ated in a laboratory in the Datian Shan Landfill. The operating
temperature of the reactor was not manually controlled, and it
was ranged from 15 to 35 °C. The reactor was operated at an
influent flow of 10–15 L h
1
, and dissolved oxygen of the upper
reactor at 0–0.5 mg L
1
.
2.2. Analytical items and methods
The experiment included start-up, stabilization of operation
and investigation of treatment efficiency. The main items moni-
tored were COD, BOD, ammonia, total phosphate (TP) and the iden-
tification of the major organic compounds present. COD (open
reflux method), BOD, ammonia (nesslerization method following
distillation) and TP (vanadomolybdophosphoric acid colorimetric
method) were measured using the standard methods recom-
mended by US Environmental Protection Agency (
The major organic compounds were determined by GC/MS. As
illustrated in
, the leachate sample (1 L) was extracted with
CH
2
Cl
2
. One liter of sample was initially extracted under alkaline
condition (pH = 12) by adding drops of 1/5 (by volume) NaOH solu-
tion, then in acidic condition (pH = 2) by adding some 1/5 (by vol-
ume) H
2
SO
4
using a separating funnel. Each extraction was done
twice with CH
2
Cl
2
. The combined extract was dehydrated by anhy-
drous sodium sulfate and concentrated to 2–3 mL by rotary evap-
oration. Then the concentrated liquid was transferred into column
separation. During the separation by column separation, alkanes
were collected from the leachate by adding n-hexane, aromatic
hydrocarbons were collected from the leachate by adding benzene,
and nonhydrocarbons were collected from the leachate by adding
ethanol. Each extract was concentrated to about 1 mL, respectively
for further analysis.
GC/MS analysis was performed using a HP5890II GC/5972 MSD
apparatus, equipped with DB-5 MS column (30 m 0.25 mm
0.25
l
m). The chromatographic conditions were as follows: the
carrier gas (He) flow rate was 2.0 mL min
1
; the initial column
temperature was 80 °C (held for two min) and was raised to
290 °C at a rate of 4 °C min
1
and then held for 30 min; the injector
and transfer-line temperature was 280 °C; the injection volume
was 1
l
L and the split ratio was 1:10. MS detected at voltage
1.05 kV, EI 50 eV, scan field 50–500 m/z, and ion source tempera-
ture 200 °C.
SAA bio-reactor
desilter
regulating tank
air compressor
Fig. 1. Schematic diagram of simultaneous aerobic and anaerobic bio-reactor
system.
organic phase
aqueous phase
aqueous phase
organic phase
concentrated liquid
separation by column separation (silica gel:alumina = 2:1)
alkane
aromatic hydrocarbon
landfill leachate (1 L)
adjustment for pH = 12 by adding NaOH
extraction (twice) by adding CH
2
Cl
2
adjustment for pH = 2 by adding H
2
SO
4
extraction (twice) by adding CH
2
Cl
2
concentration by rotary evaporator
leaching by n-hexane
leaching by benzene
nonhydrocarbon
leaching by ethanol
Fig. 2. The analysis process of organic pollutant in leachate.
1752
Z. Yang, S. Zhou / Chemosphere 72 (2008) 1751–1756
3. Results and discussion
3.1. The characteristics of landfill leachate
Datian Shan landfill site was located on the northwestern side
of Datian Shan mountain, approximately 26 km east of Guangzhou
city, South China. It has been in operation as a disposal facility, per-
mitted to receive commercial and municipal solid waste, since
1987. The solid waste placed in this landfill came from houses,
streets, restaurants, shops, food markets and companies. Initially,
the designed area was 0.17 km
2
and filling capacity was
1.69 10
6
m
3
. After enlargement, the capacity was nearly 4.15
10
6
m
3
. Up to 2000, the waste delivered was over 2 10
6
kg d
1
,
which was nearly the half amount of waste in Guangzhou.
The site was based on cultivated soil, natural clay and semi-
impermeable clay layer with average thickness of 1.8 and 2.0 m,
respectively. Before the operation of the landfill site, the clay layer
was compacted to prevent leachate movement. The tubes were in-
stalled to collect the leachate, which was discharged into a leach-
ate collection pool. Its major characteristics are shown in
The BOD/COD ratio of the leachates was above 0.3, which indicated
the raw leachate could be biologically treated.
3.2. Removal efficiency of main pollutants in landfill leachate
The bio-reactor was dosed with sludge from the bio-treatment
tank of Jiangmen landfill leachate treatment plant in Guangdong
province. After the bio-reactor was run for several months, the
treatment efficiency of the bio-reactor stabilized. The operation
of the bio-reactor was monitored to provide an insight into its effi-
ciency in reducing the concentrations of organics and ammonia in
this leachate.
3.2.1. Removal efficiency of COD in landfill leachate
a shows the temporal variations of COD concentration and
COD removal efficiency in the influent and effluent of the SAA bio-
reactor system during stable operation. With the degradation of
landfilled refuse, the influent COD concentration in the SAA bio-
reactor system increased at the early stage, and reached maximum
value of 3300 mg L
1
on day 17, then decreased to 1300 mg L
1
on
day 28. During other experiments, the influent COD concentration
varied from 1000 to 3300 mg L
1
. This could be attributed to vari-
ation in the composition of the landfilled refuse (
Under the SAA condition, the efficiency of COD removal ranged
from 85% (on day 4) to 95% (on day 53), and the average removal
efficiency was 94%. Although the COD concentration of the influent
changed greatly, the COD concentration of the effluent remained
Table 1
Seasonal variation in chemical properties for Datian Shan landfill leachate
item
Landfill leachate
Color
Yellow–black
pH
6.0–9.0
Alkalinity as CaCO
3
, (mg L
1
)
4040–22 100
COD (mg L
1
)
3780–28 100
BOD (mg L
1
)
1040–11 300
NH
þ
4
-N, mg IT
1
1040–3560
T-P (mg L
1
)
11–18
SS (mg L
1
)
850–5840
COD=NH
þ
4
-N
2–32
BOD/COD
0.3–0.7
10
20
30
40
50
60
70
80
10
20
30
40
50
60
70
80
0
3500
3000
2500
2000
1000
1500
500
COD, mg l
-1
E f f i c i e n c y
I n f l u e n t
E f f l u e n t
100
80
70
60
50
40
30
20
10
0
90
100
80
70
60
50
40
30
20
10
0
90
COD removal eff., %
240
220
200
180
160
140
120
100
80
60
40
20
0
Time, days
NH
4
+
-N
, mg
l
-1
E f f i c i e n c y
I n f l u e n t
E f f l u e n t
NH
4
+
-N
re
mov
a
l eff., %
b
a
Fig. 3. Influent and effluent COD, ammonia concentrations and efficiencies.
Z. Yang, S. Zhou / Chemosphere 72 (2008) 1751–1756
1753
below 300 mg L
1
. Total COD removal efficiency of the system re-
mained stable, which showed that the microorganisms in the
SAA bio-reactor could deal with organic pollutant stably despite
variation in the COD concentration of influent.
3.2.2. Removal efficiency of ammonia in landfill leachate
The variation of ammonia concentration and ammonia removal
efficiency in the SAA bio-reactor process is presented in
b. The
slow leaching of nitrogen from solid waste in landfills resulted in
high concentration of ammonia in the landfill leachate, which
might last for decades. The influent NH
þ
4
-N concentration varied
from 80 to 230 mg L
1
, and the average influent NH
þ
4
-N concentra-
tion was 163 mg L
1
. The average NH
þ
4
-N effluent concentration
was 7 mg L
1
, and the average removal efficiency was 95%.
Although the influent NH
þ
4
-N concentration varied, the effluent
NH
þ
4
-N concentration remained below 25 mg L
1
, which is the
effluent discharge standard II for this kind of waste water in China.
It implied that biological nitrogen removal took place in the SAA
reactor, because of the combination of aerated and anaerobic pro-
cesses with a high organic content. A high COD concentration
might stimulate the faster growth of heterotrophic bacteria, which
would consume oxygen and nutrients rapidly (
). As a result, there was a decrease of dissolved oxygen con-
centration in the down-flow zone as water flows from the inner
zone to the outer zone. It resulted in co-existence of nitrifiers
and denitrifiers. The microorganisms in the SAA bio-reactor could
deal with ammonia stably despite variation in the influent ammo-
nia concentration. A certain ammonia was produced by ammonifi-
cation of organic nitrogen, which may be also removed by the
reactor. The removal efficiency of ammonia may be underesti-
mated in the SAA bio-reactor.
3.3. Removal efficiency of organic pollutants in landfill leachate
In order to observe if there was a preferential removal of landfill
leachate components, such as alkanes or aromatic hydrocarbons, a
GC–MS analysis was conducted with n-hexane and benzene. On
day 70 after stabilization of the SAA bio-reactor system, three dif-
ferent influent and effluent samples were taken to be measured.
Every sample was measured by GC/MS for three times on the same
condition. All the compounds were identified by library (WILEY)
search.
shows the chromatogram for different groups of
organics in the landfill leachate. This chromatogram revealed the
presence of various groups of organic components in landfill leach-
ate, such as aromatic hydrocarbons and alkanes. Landfill discharges
are complex mixtures of organics. Treatment in the bio-reactor de-
creased the concentrations of most alkanes, aromatics and other
types of organics. In particular, there was a shift to lower molecular
weights, implying the decomposition of the complex compounds.
The chromatogram revealed the presence of at least 87 types of
organic components in the landfill leachate, which included 17 alk-
anes and olefins, 28 aromatic hydrocarbons, 6 acids, 4 esters, 17
alcohols and hydroxybenzenes, 7 aldehydes and ketones and 4
amides. Many of these compounds have complicated structures
that are unfavorable to the environment. To enable a quantitative
comparison of the relative removal of alkanes and aromatic com-
pounds from the leachate to be made, the areas of the peaks under
the chromatograms were determined under the same condition.
Some alkanes were detected in the landfill leachate. Most of the
alkanes were highly saturated alkanes. Among them, nine alkanes
belong to the US EPA list of priority environmental pollutants
(
), including tetradecane, hexadecane, octadecane,
eicosane, docosane, tetracosane, hexacosane, octacosane and tria-
contane. Some highly saturated alkanes also could be removed or
degraded by an optimal anaerobic and aerobic process.
gives the concentrations of some target alkane compounds in the
landfill leachate samples. Tetradecane, pentedacane, heptadecane,
triacontane were totally removed. Heneicosane, tetracosane, hex-
acosane, octacosane and nonacosane were reduced by over 50%.
There were still some refractory alkanes, such as hexadecane, octa-
decane, nonadecane, eicosane, docosane, tricosane, pentacosane
and heptacosane. Many studies have demonstrated that an abun-
dance of alkanes degrader was involved in microbial degradation
of alkanes (
Da Cunha et al., 2006; van Beilen and Funhoff, 2007
).
asdsggf
asdsggf
asdsggf
10
20
30
40
50
60
70
80
10
20
30
40
50
60
70
80
Time, mi
n
Time, mi
n
Time, mi
n
Time, mi
n
10
20
30
40
50
60
70
80
10
20
30
40
50
60
70
80
2.4
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0.2
0.4
0.6
0.
8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.6
2.8
0
2.4
0.2
0.4
0.6
0.
8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.6
2.8
3.0
0
0
Abundance, millions
0.2
0.4
0.6
0.
8
1.0
1.2
1.4
1.6
1.8
2.0
0
Abundance, millions
Abundance, millions
Abundance, millions
(a) influent alkanes
(b) influent aromatic hydrocarbon
(c) effluent alkanes
(d) effluent aromatic hydrocarbo
n
Fig. 4. Chromatogram of leachate.
1754
Z. Yang, S. Zhou / Chemosphere 72 (2008) 1751–1756
The relative concentrations of the aromatic compounds as mea-
sured by their chromatograph areas are shown in
. Seven
belong to the US EPA list of priority environmental pollutants.
There were naphthalene, pyrene, phenanthrene, fluoranthene, flu-
orene, methylbenzene and phenol. Among the various remediation
technologies available for treating water contaminated with aro-
matics, biological methods or bioremediation processes appear to
be a potentially economical, energy efficient and environmentally
sound approach (
). The aromatics tend to be more
recalcitrant and therefore their removal from water is highly desir-
able. The results indicate that the microorganisms in the bio-reac-
tor removed a high proportion of aromatics.
The concentration of organic pollutants in landfill leachate was
greatly decreased by the SAA bio-reactor. Ex-situ bioremediation
through biological reactors, both under aerobic and/or anaerobic
conditions, has been successfully used in the treatment of water
contaminated with chemical pollutants including perchlorate, bro-
mate, chlorinated hydrocarbons such as trichloroethylene, phenol,
methyl tert-butyl ether and other oxygenated compounds, alkyl-
ate, polycyclic aromatic hydrocarbon, monoaromatic compounds,
fuel hydrocarbons (oil, gasoline and diesel) and other organic com-
pounds. As shown in
, 31 organic compounds were removed
completely, the concentrations of 14 organic compounds were re-
duced by more than 80% and the removal efficiencies of a further
25 organic compounds were over 50%. The effective removal of
these compounds reduced the harmful effect on the receiving
watercourse. These results are coincident with the COD removal
efficiency.
3.4. Biological treatability by the SAA bio-reactor system
This study has demonstrated that the SAA bio-reactor system
can be a promising alternative option to the conventional activated
sludge process for the effective biological removal of organic and
nitrogenous matter from landfill leachates.
summarized
various
SBR
processes
in
landfill
leachate
(COD = 1000–3000 mg L
1
), and concluded that the highest re-
moval efficiencies of COD and ammonia were 75% and 90%, respec-
tively. This removal efficiency is lower than that in the SAA
Table 2 (Continued)
Organic pollutant
Influent
content
Effluent
content
Removal
efficiency
2(1H)-Naphthalenone,
1.26
0.55
66
Octahydro-4a,7,7-trimethyl-, cis-
Decalone
0.81
–
100
2-Oxazolidinone,
0.71
–
100
5-metyl-4-phenyl-,cis-3H-Pyrazol-3-
one
2.33
1.62
45
1,2-dihydro-1,2,5-trimethyl-
0.51
0.21
68
Phenol, 4-methyl-
1.95
2.00
19
Phenol,2,6-bis
0.35
0.35
22
(1,1-dimethylethyl)-4-methyl-
Phenol,4-
0.63
0.38
53
(1,1,3,3-tetramethylethyl)-Phenol,4,4’-
1.57
0.56
72
(1-methylethylidene)bis-Phenol,4-
proply-
2.96
1.35
64
Phosphoric acid, triethyl ester
0.54
–
100
Carboxylic acid, 2-ethyl-3-phenyl,
ethyl-, oxirane ester
0.51
–
100
Ethanone,2,2-dimethoxy-1,2-
diphenyl-
0.61
0.62
20
1,2-Benzenedicarboxylic acid, dibutyl
ester
1.35
1.11
35
2,4,8,10-Tetraoxaspiro[5,5]undecane
0.41
0.39
25
Bicyclo[2.2. 1]heptane, 2-ethylidene-
1,7,7-trimethyl-,(E)
2.11
2.03
25
Succinic acid,2,3-diethyl-
1.16
0.41
72
Valeric acid, 4-phenyl-
1.33
1.03
39
*
Organic pollutants in the US EPA list of priority pollutants in environment.
Table 2
GC-MS analysis result about organic pollutant after and before removing refuse
leaching (%)
Organic pollutant
Influent
content
Effluent
content
Removal
efficiency
0.68
–
100
Pentedacane
1.49
–
100
1.45
1.54
20
Heptadecane
1.18
–
100
2.36
2.56
10
Nonadecane
1.44
1.73
10
1.95
2.54
3
Heneicosane
1.95
1.56
56
2.78
2.27
9
Tricosane
3.07
2.63
13
2.86
1.78
53
Pentacosane
3.29
4.07
8
4.73
3.71
56
Heptacosane
3.31
3.78
11
3.88
2.01
57
Nonacosane
5.04
2.28
62
4.14
–
100
1.36
0.35
70
0.20
–
100
0.50
–
100
0.32
0.17
38
Carboline
0.56
0.092
81
1H-Indole, 3-methyl-
0.38
0.26
21
1.05
–
100
Camphor
2.73
–
100
Eucalyptene
2.73
–
100
beta-Bisabolene
0.067
–
100
Indene
1.38
0.20
83
Acetamide, N-cyclohexyl-
2.17
0.36
81
Benzoylamide
0.30
–
100
N,N-bimethyl-3-methyl-9-
Octadecenamide,(z)-
0.065
–
100
Methy lbenzene
0.20
–
100
1,2,4-Trimethylbenzene
0.28
–
100
Benzothiazole
0.042
–
100
4-Methylbenzene, 1-(1,5-bimethyl-4-
hexene)
1.31
0.41
63
Benzene, 3,4-bifluorine-4-methoxyl-
1.79
0.27
82
Benzenesulfonamide
2.58
1.07
67
N-ethyl-4-methyl-2(3H)-Benzothiazolone
0.44
–
100
Thiophene
0.68
0.19
67
2-ethyl-5-heptyl-Phenanthridine, 5-oxide
1.65
0.32
77
10-Demethylsqualene
0.13
–
100
Cholest-4-en-3-one
0.28
–
100
2,6,10,14,18,22-Tetracosahexaene
3.06
1.25
68
2,6,10,15,19,23-hexamethyl-Cholestane, 3-
ethoxy-, (3.beta., 5.alpha)-
1.04
–
100
Pentanoic acid, 2-methyl-, anhydride
1.65
0.98
53
1H-Indene-4-acetic acid, 6-(1,1-
dimethylethyl)-2,3-
1.78
0.17
92
dihydro-1,1-dimethyl-Hexadecanoic
0.13
–
100
Octadecanoic
1.26
0.42
74
Naphthalene, 1,2-dihydro-1,1,6-trimethyl-
1.65
0.37
82
Naphthalene, 1,3-bimethyl-
0.26
–
100
Naphthalene,2-bimethyl-
0.32
–
100
Naphthalene,2-vinyl-
0.15
–
100
Benezofluorene,5-hydroxyl-11-carbonyl-
1.31
0.25
85
Urea
1.89
0.23
90
Urea,N,2-propyl-N-1H-6-purine-
2.10
0.45
83
1-.alpha.-Terpineol
3.31
0.81
81
Benzenemethanol
3.31
1.01
76
Cedrol
1.49
–
100
Cyclohexanol,3,3,5-trimethyl-
17.13
3.44
84
Glycol
1.26
0.63
61
8-Quinolinol, 2-methyl-
2.31
1.44
51
1,4-Benzenediol,2-(1,1-dimethylethyl)-
0.14
–
100
Coprostenol
2.97
1.56
59
Dihydrocholesterol
1.91
0.96
60
Ethanol, 2-cholro-, phosphate(3:1)
1.21
0.68
56
Menthone
0.60
–
100
Cyclothexanone,3,3,5-trimethuyl-
3.73
0.31
93
2,5-Cyclohexadiene-1,4- dione, 2,6-bis(1,
1-dimethylethyl)-
0.54
0.36
47
Benzophenone
0.37
–
100
Z. Yang, S. Zhou / Chemosphere 72 (2008) 1751–1756
1755
bio-reactor system. Continues flow in SAA system could also im-
prove the utilization efficiency of reactor. Because of high pool
capacity utilization and SAA process, the SAA bio-reactor system
achieved a higher degree of organic carbon removal than SBR pro-
cess. As for the SAA biotechnology,
used on-site
anaerobic–aerobic lagoons and constructed wetlands for biological
treatment of landfill leachate. Overall N, P and Fe removals ob-
tained in this system were up to 70% for diluted leachate. The re-
moval efficiency by lagoon and constructed wetland is lower
than that by the SAA bio-reactor system. And the SAA bio-reactor
system is superior to constructed wetland process in area extent
and operation management. With its aerobic process in the inner
cylinder and anaerobic process in the out cylinder, this simple
mode of operation almost entirely removed carbon and nitrogen
in the diluted landfill leachate wastewater.
The complexity of the SAA bio-reactor system is quite low and
maintenance therefore requires few specialized skills. Energy con-
sumption, if any, is usually limited to pump and air compressor.
Chemicals are rather rarely applied. Simple operation and mainte-
nance have made the SAA bio-reactor system a good choice for
wastewater treatment, particularly in developing countries since
there is a little need for specialized skills to run the system.
4. Conclusions
An innovative reactor (SAA bio-reactor) was developed and
demonstrated herein to treat diluted landfill leachate. In order to
evaluate the biological treatability of the landfill leachate, the re-
moval efficiency of COD, ammonia and organic pollutants were
investigated. The following conclusions could be obtained.
Landfill leachate generated from Datian Shan landfill site was of
very poor quality, with high concentrations of numerous organic
pollutants. The COD concentration was between 3780 and
28 100 mg L
1
. The BOD concentration was between 1040 and
11 300 mg L
1
. The COD and NH
þ
4
-N removal efficiency was about
94% and 95%, respectively after treatment in the SAA bio-reactor.
The average effluent concentrations of COD and NH
þ
4
-N were 131
and 7 mg L
1
, respectively, both below the permissible limit for
Chinese
second
grade
effluent
(COD < 300 mg L
1
,
NH
þ
4
-N <
25 mg L
1
).
About 87 organic compounds in the landfill leachate were iden-
tified by GC-MS analysis, and 16 of them are on the US EPA list of
environmental priority pollutants. Of the organic compounds, 31
were completely removed, the concentrations of 14 were reduced
by at least 80% and the removal efficiencies of a further 25
exceeded 50%, coincident with the COD removal efficiency.
Acknowledgements
The research was supported by the National Ministry of Educa-
tion and the Guangdong Provincial Department of Science and
Technology (Project Nos. 2002C32108, 2006B36703002).
References
APHA, 1998. Standards Methods for the Examination of Water and Wastewater,
20th ed. American Public Health Association, Washington, DC, USA.
Atuanya, E.I., Purohit, H.J., Chakrabarti, T., 2000. Anaerobic and aerobic
biodegradation of chlorophenols using UASB and ASG bio-reactors. World J.
Microb. Biot. 16, 95–98.
Benfenati, E., Porazzi, E., Bagnati, R., Former, F., Martinex, M.P., Mariani, G., Fanelli,
R., 2003. Organic tracers identification as a convenient strategy in industrial
landfills monitoring. Chemosphere 51, 667–683.
Berge, N.D., Reinhart, D.R., Dietz, J., Townsend, T., 2006. In situ ammonia removal in
bio-reactor landfill leachate. Waste Manage. 26, 334–343.
Bodzek, M., Surmacz-Górska, J., Hung, Y.T., 2004. Treatment of landfill leachate. In:
Wang, L.K., Hung, Y.T., Lo, H.H., Yapijakis, C. (Eds.), Handbook of Industrial and
Hazardous Wastes Treatment. Marcel Dekker, New York, pp. 1155–1208.
Burnley, S.J., Ellis, J.C., Flowerdew, R., Poll, A.J., Prosser, H., 2007. Assessing the
composition of municipal solid waste in Wales. Resour. Conserv. Recy. 49, 264–
283.
Calli, B., Mertoglu, B., Inanc, B., 2005. Landfill leachate management in Istanbul:
applications and alternatives. Chemosphere 59, 819–829.
Canziani, R., Emondi, V., Garavaglia, M., Malpei, F., Pasinetti, E., Buttiglieri, G.,
2006. Effect of oxygen concentration on biological nitrification and microbial
kinetics in a cross-flow membrane bio-reactor (MBR) and moving-bed
biofilm reactor (MBBR) treating old landfill leachate. J. Membrane Sci. 286,
202–212.
Castillo, E., Vergara, M., Moreno, Y., 2007. Landfill leachate treatment using a
rotating biological contactor and an upward-flow anaerobic sludge bed reactor.
Waste Manage. 27, 720–726.
CEMRG (China Environmental Monitoring Research Group), 1989. Priority
Pollutants in Environment. China Environment and Science Press, Bejing,
China. in Chinese.
Chen, S., Sun, D., Chung, J.S., 2008. Simultaneous removal of COD and ammonium
from landfill leachate using an anaerobic–aerobic moving-bed biofilm reactor
system. Waste Manage. 28, 339–346.
Chiang, L.C., Chang, J.E., 2001. Electrochemical oxidation combined with physical-
chemical pretreatment processes for the treatment of refractory landfill
leachate. Environ. Eng. Sci. 18, 369–379.
Da Cunha, C.D., Rosado, A.S., Sebastia’n, G.V., Seldin, L., Von Der Weid, I., 2006. Oil
biodegradation by Bacillus strains isolated from the rock of an oil reservoir
located in a deep-water production basin in Brazil. Appl. Microbiol. Biot. 73,
949–959.
Hallbourg, R.R., Delfino, J.J., Larnar, M.W., 1992. Organic priority pollutants in
groundwater and surface water at three landfill in north central Florida. Water
Air Soil Poll. 65, 307–322.
Ho, S., Boyle, W.C., Ham, R.K., 1974. Chemical treatment of leachate from sanitary
landfills. J. Water Pollut. Con. F. 46, 1776–1791.
Kjeldsen, P., Barlaz, M.A., Rooker, A.P., Baun, A., Ledin, A., Christensen, T.H., 2002.
Present and long-term composition of MSW landfill leachate: a review. Crit.
Rev. Env. Sci. Tec. 32, 297–336.
Koshy, L., Paris, E., Ling, S., Jones, T., Bérubé, K., 2007. Bioreactivity of leachate from
municipal solid waste landfills – assessment of toxicity. Sci. Total Environ. 384,
171–181.
Maehlum, T., 1995. Treatment of landfill leachate in on-site lagoons and
constructed wetlands. Water Sci. Technol. 32 (3), 129–135.
Mikac, N., Cosovic, B., Ahel, M., Andreis, S., Toncic, Z., 1998. Assessment of
groundwater contamination in the vicinity of a municipal waste landfill. Water
Sci. Technol. 37 (8), 37–44.
Ntampou, X., Zouboulis, A.I., Samaras, P., 2006. Appropriate combination of physico-
chemical methods (coagulation/flocculation and ozonation) for the efficient
treatment of landfill leachates. Chemosphere 63, 722–730.
Patureau, D., Bernet, N., Moletta, R., 1997. Combined nitrification and denitrification
in a single aerated reactor using the aerobic denitrifier Comamonas sp. strain
SGLY2. Water Res. 31, 1363–1370.
Pivato, A., Gaspari, L., 2006. Acute toxicity test of leachates from traditional and
sustainable landfills using luminescent bacteria. Waste Manage. 26, 1148–
1155.
Puznava, N., Payraudeau, M., Thornberg, D., 2001. Simultaneous nitrification and
denitrification in biofilters with real-time aeration control. Water Sci. Technol.
43 (1), 269–276.
Renou, S., Givaudan, J.G., Poulain, S., Dirassouyan, F., Moulin, P., 2008. Landfill
leachate treatment: review and opportunity. J. Hazard. Mater. 150, 468–493.
Rivas, F.J., Beltrán, F., Carvalho, F., Acedo, B., Gimeno, O., 2004. Stabilized leachates:
sequential coagulation-flocculation + chemical oxidation process. J. Hazard.
Mater. 116, 95–102.
Seo, D.J., Kim, Y.J., Ham, S.Y., Lee, D.H., 2007. Characterization of dissolved organic
matter in leachate discharged from final disposal sites which contained
municipal solid waste incineration residues. J. Hazard. Mater. 148, 679–692.
Shim, H., Shin, E.B., Yang, S.T., 2002. A continuous fibrous-bed bio-reactor for BTEX
biodegradation by a co-culture of Pseudomonas putida and Pseudomonas
fluorescens. Adv. Environ. Res. 7, 203–216.
Smith, V.H., 2003. Eutrophication of freshwater and coastal marine ecosystems: a
global problem. Environ. Sci. Pollut. Res. 10, 126–139.
Tartakovsky, B., Manuel, M.F., Guiot, S.R., 2005. Degradation of trichloroethylene in
a coupled anaerobic–aerobic bio-reactor: modeling and experiment. Biochem.
Eng. J. 26, 72–81.
van Beilen, J.B., Funhoff, E.G., 2007. Alkane hydroxylases involved in microbial
alkane degradation. Appl. Microbiol. Biot. 74, 13–21.
Zhou, S.Q., Tang, L.M., Yao, R.H., Feng, P.S., 1998. Numerical analysis of
hydrodynamics in IALR ecosystem (I): the fields of flow, pressure and shear
stresses. J. South China Univ. Tech. 26, 77–82. in Chinese.
Zhou, S.Q., Yao, R.H., Chen, K.F., 1999. Namerical analysis of hydrodynamics in IALR
(II): the effects of conical angle on the fields of flow, pressure and shear stresses.
J. South China Univ. Tech. 27, 33–37. in Chinese.
1756
Z. Yang, S. Zhou / Chemosphere 72 (2008) 1751–1756
Document Outline
- The biological treatment of landfill leachate using a simultaneous aerobic and anaerobic (SAA) bio-reactor system
- Introduction
- Materials and methods
- Results and discussion
- Conclusions
- Acknowledgements
- References
Wyszukiwarka
Podobne podstrony:
opracowanie moje 1 24 id 338286 Nieznany
24[2]. moje OBLICZENIA, Studia, Fizyka, LABORKI
moje, Katecheza 24, Katecheza 24
Gazeta Prawna Moje nieruchomości Mój portfel z 24 lipca 09 (nr 143)(1)
Księżyc 24-03-2015 rok, Dokumenty i opracowania, Astronomia, Moje obserwacje, Obserwacje Księżyca, 2
cwiczeni nr 24, studia, Budownctwo, Semestr II, fizyka, Fizyka laborki, Fizyka - Labolatoria, MOJE C
Chemia fiz. - moje spraw, 24 kineryka rozkładu jonowego kompleksu trójszczawianomanganowego, Marzena
Moje Ćw 24, POLITECHNIKA ŁÓDZKA, Technologia Żywności i Żywienia Człowieka, semestr 4, Chemia fizycz
24 Travelling (moje)
Praktyczna Nauka Języka Rosyjskiego Moje notatki (leksyka)24
24 piątek
24(45)RUP
ostre białaczki 24 11 2008 (kurs)
ZPSBN T 24 ON poprawiony
więcej podobnych podstron