Sludge? Effluent. Influent. Secondary settler. Primary settler. Aeration tank.
Recycled activated biomass. Primary sludge. Secondary sludge. (waste activated
...
Biogas Production from Biological Sludge
D. J. Lee Department of Chemical Engineering National Taiwan University
Sludge? ASM
Influent
Aeration tank Effluent
Primary settler
Secondary settler Recycled activated biomass
Primary sludge
Filtration
Secondary sludge (waste activated sludge)
Digester
Flocculation
Thickener
Dewatering facility Pretreatment
Settling
Biological Sludge Floc Floc is a common form of bioaggregates appearing in the wastewater treatment process. •Irregular shape; •Highly porous; •Compressible and fragile; •Inhomogeneous distribution of internal mass.
Sludge Floc
•A group of symbiotic microorganisms “embedded” in the extracellular Frolundpolymers (1994)
Biogas pH 5-6
pH 7-8
Anaerobic digestion Fermentative bacteria
Acidogenesis Hydrolysis
5%
20%
Complex biopolymers (Carbohydrate/ protein/ lipids) 75%
10%
35%
Organic monomers (sugar/ amino acids/ fatty acids) 30%
Long Long chain chain VFA(C3/C4/i-C4/C5/C6) VFA(C3/C4/i-C4/C5/C6) alcohol/methanol/lactate/formate/butanol/acetone alcohol/methanol/lactate/formate/butanolacetone
Acetogenesis
Acetogenic B.
13%
H2/CO2
17%
Acetate
Homoacetogenic B.
Methanogenesis
Acetoclastic B.
CH4/CO2/H2O 28%
72%
Hydrogenophilic B.
O △G ′ Step Fermentation
C6 H12O6 + 4 H 2O → 2CH 3COO− + 2 HCO− + 4 H + + 4H 2 3
C6 H12O6 + 2 H 2O → CH 3 (CH 2 ) 2 COO − + 2 HCO − + 3H + + 2 H 2 −
−
3
3C6 H12O6 → 4CH 3CH 2COO + 2CH 3COO + 2CO2 + 2 H 2O + 2 H + + H 2 → CH 3COO − + H + + 2 H 2 CH 3CH 2OH + H 2O
Acetogenesis
→ CH 3COO − + H + + 3H 2 + HCO3− CH 3CH 2COO − + 3H 2O
→ 2CH 3COO − + H + + 2 H 2 CH 3 (CH 2 ) 2 COO − + 2 H 2O → CH 3COO − + 4 H 2O 2 HCO3− + 4 H 2 + H + → CH 4 + 2 H 2O CO2 + 4 H 2 −
+
4 HCOO + 4 H → CH 4 + 3CO2 + 2 H 2O
Methanogenesis
4CO + 2 H 2O → CH 4 + 3CO2
→ CH 4 + CO2 CH 3COO − + H + 4CH 3OH → 3CH 4 + CO2 + 2 H 2O
4(CH 3 ) 3 NH + + 6 H 2O → 9CH 4 + 3CO2 + 4 NH 4+
-207 -135 -922 +10 +76 +48 -105 -130 -120 -186 -33 -309 -666
Step Denitrification
12 NO3− + C6 H12O6 →12 NO2− + 6CO2 + 6 H 2O 8 NO2− + C6 H12O6 → 4 N 2O + 6CO2 + 6 H 2O
12 N 2O + C6 H12O6 →12 N 2 + 6CO2 + 6 H 2O
Sulphate reduction
4 H 2 + SO42− + H + → 4 H 2O + HS −
CH 3COO − + SO42− → 2 HCO3− + HS −
4CH 3CH 2COO − + 3SO42− → 4CH 3COO − + 4 HCO3− + H +
-1946 -632 -134 -152 -48 -151
Phase Fermenting Bacteria pH=5.2~6.3 YX=0.2g-VS g-COD-1 Faculative anaerobic
Acedogenesis and Methadogenesis pH=6.8~7.2 YX=0.03~0.05 g-VS g-COD-1 Obligate anaerobic Syntrophic reaction Interspecies hydrogen transfer
Propionate and H2 Propionate: account for over 30% of the electron flow Deterioration of propionate degradation Æ Decrease in VFA removal efficiency -10 1/2CH3CH2OH+1/2H2OÆ1/2CH3COOH+H2
-8
△Go(W)
-6
kCal
-4
H2+1/2CO2Æ1/2CH4+1/2H2O
1/2CH3COOHÆ1/2CH4+1/2CO2
1/3CH-2 3CH2COOH+2/3H2OÆ 1/3CH3COOH+1/3CO2+H2
0 Region for Ethanol to CH4
Region for Propionate to CH4
2 -8
-7
-6
-5
-4
-3
-2
-1
0
Log(H2) McCarty, P.L. and Smith, D.P. Anaerobic wastewater treatmen [J]. Environ. Sci. Technol., 1986,20:1200-1206
Through enzymes
Enhanced Hydrolysis
100 µ m
FT
p
Na-salt
TT
pH 3
1 1 H
US
Pre-hydrolysis Pre-hydrolysis of sludge is often applied in prior to the anaerobic digestion to: Disintegrate the suspended particles Decompose the insoluble organic molecules.
Alkaline treatment and ultrasonication were reported as effective prehydrolytic treatments.
Enhancing Digestion
Waste Activated Sludge Sampling from the recycled stream in the secondary treatment stage in St. Marys sewage treatment plant in Sydney, Australia. pH = 7.50 TSS = 10,700 mg/L. ρS = 1,612 kg/m3.
(a)
(b)
Strains in innoculum K8: (a) bacillus; (b) cocci.
Flocculation retards Digestion; while Ultrasonication Enhances it.
After sonication Original Flocculated
200
100
Before sonication Original Flocculated 0 0
10
20
30
40
90
100
Time (day) 10 -200
Before sonication Original Flocculated After sonication Original Flocculated
-250
After sonication Original Flocculated
8
ATP content (µg/L)
ORP (mV)
Methane production (g/kg DS)
300
-300
6
4
Before sonication Original Flocculated
2
0
-350 0
10
20
30
Time (Day)
40
90
100
0
10
20
30
Time (Day)
40
90
100
400
Before sonication Original Flocculated
df[4,3] (µm)
300
Poor digestion
200
80
After sonication Original Flocculated
60
40 0
10
20
30
Time (Day)
40
90
100
100 µm
Ori, 0 & 30 d
Floc, 0 & 30 d
Ori, 0 & 30 d
Floc, 0 & 30 d
Insufficient Challenge
0.11 W/cm3
Floc size (µm)
100
0.22 W/cm3 50 0.11 Watt/ml 0.22 Watt/ml
0.33 W/cm3
0.33 Watt/ml 0.44 Watt/ml
0 0
50 Sonication time (min)
100
R3 leachate
Rm effluent
COD (g/L)
14 7 0 2
R1 leachate
Rm CH4 yield
Rm CH4 content
80
21
0
R1/R2/R3 CH4 yield
4 6 8 operation time (day)
R2 leachate
R3 leachate
10
12
100 80
60
60 40 40 20
20 0
0 0
2
R1 leachate 8.0
Rm effluent
18
CH4 content (%)
R2 leachate
cumulative CH 4 yield (L)
R1 leachate 28
4 6 8 operation time (day)
R2 leachate
10
R3 leachate
12
Rm effluent
7.0 12
pH
TVFA (g/L)
15
9 6
6.0 5.0
3
4.0
0 0
2
4 6 8 operation time (day)
10
12
0
2
4 6 8 operation time (day)
10
12
Full-Scale Landfill Site
Sustainable Landfill Simulative rainfall
Leacahte recycling
Leacahte recycling
Fresh
Fresh
Fresh
layer
layer
layer
Column No.1
No. 2
No.3-5
Pretreatment
Internal Circulation
Leachate Aerobic SBR
Gas sample Leachate
Ana UFB
Old layer
80
COD(g/L)
60
column column column column column
40
No.1 No.2 No.3 No.4 No.5
20
0 0
5
10
15
20
25
30
week 9.0
Biogas production
(a)
7.5
pH
6.0 column column column column column
4.5 3.0
No.1 No.2 No.3 No.4 No.5
1.5 0
5
10
15
20
25
30
week
100 column column column column column
CH4 concentration(%)
80
60
No.1 No.2 No.3 No.4 No.5
40
20
0 0
5
10
15 week
20
25
30
天子岭Site in HangZhu
pH 5-6
pH 7-8
Hydrogen from waste Hydrogen production by pure substance or mixture molasses (Tanisho and Ishiwata, 1994) glucose (Kataoka et al., 1997; Lin and Chang, 1999) crystalline cellulose (Lay, 2001) peptone (Bai et al., 2001) starch (Lay, 2001) Hydrogen production by concentrated wastewater (Bolliger et al., 1985 ; Liu et al., 1995 ; Ueno et al.,1996 ; Zhu et al., 1999) Hydrogen production by solid waste municipal solid waste (Lay et al., 1999) bean curd manufacturing waste (Mizuno et al., 2000 ) Hydrogen production by biological sludge ???
Min-sheng Sludge Concentration of wet solids
10,000~12,000 mg/L
Concentration of dry solids
1,429 kg/m3
pH value
6.4
Neutron particle size
71.6 µm
Zeta potential
-19.1 mV
TCOD
24,800 mg/L
SCOD
435 mg/L
alkalinity
325 mg/L
Elemental composition
C 34.3%、H 5.3%、N 5.4%、O 55 %
63µm 63µm 63µm 63µm
Tong-yi Sludge Concentration of wet solids
10,000 mg/L
Concentration of dry solids
1,450 kg/m3
pH value
6.7
Neutron particle size
59.7 µm
Zeta potential
-24.7 mV
TCOD
16,000mg/L
SCOD
86.7 mg/L
alkalinity
410 mg/L
Elemental composition
C 41.3%、H 6.6%、N 5.4%、O 46.7%
63µm 63µm
Strains screening
DNA sequencing
Finding optimal dealing parameters
Concentration
Pretreatment methods
Inhibitors
Measuring time points
Continuous anaerobic experiments
Gas production
Hydrogen productive substrates
Composition analysis
Strains screening (1) Screening
Strains screening (2) Add them individually
Test the ability of hydrogen production
M-B
M-D
M-F
M-G
The ability of hydrogen production is about 0.65-1.11 H2/kg DS
Species identification Extract DNA
PCR F8 R1510
Compare to the gene library
GCGGGNGNGGTNCC TAACACATGCAAGT CGTAACANGGTATT CCACANCAGNGNGC TGGACGGACNNGNA ACAGAGG…...
purification
purification
sequencing
Continuous sequencing
DNA Sequence
M-B M-D M-F M-G
Clostridium bifermentans
Clostridium bifermentans
Pretreatment flow chart Ultrasonication
Acidification
Original sludge
Pasteurization
Add BESA
Freeze-thaw treatment
Original sludge Filtrate
Pasteurized Filtrate
Ultrasonicated BESA adding Filtrate Filtrate
Acidified Filtrate
Freeze-thawed Filtrate
Sludge fermentation test - COD COD0 – COD of original biosolid SCOD – Soluble COD Min-sheng sludge
Tong-yi sludge
1.0
1.0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
0.6
0.8
SCOD/COD0
SCOD/COD0
0.8
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
0.4
0.2
0.6
0.4
0.2
0.0
0.0
0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Sludge fermentation test –
Hydrogen production
CODi – COD of the substrate before testing
Min-sheng sludge
12
10
Yield of hydrogen(mg/g-CODi)
10
Yield of hydrogen(mg/g-CODi)
Tong-yi sludge
12
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
8
6
4
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
8
6
4
2
2
0
0 0
8hr
25
50
24hr Time (hours)
75
100
0
8hr
25
50
24hr Time (hours)
75
100
ludge fermentation test –
methane production
Min-sheng sludge
3.0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
2.0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
2.5
Yield of methane (mg/g-CODi)
Yield of methane (mg/g-CODi)
2.5
Tong-yi sludge
3.0
1.5
1.0
2.0
1.5
No CH4!!
1.0
0.5
0.5
0.0
0.0
0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Sludge fermentation test –
pH measuring
Min-sheng sludge
8
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
7
Tong-yi sludge
8
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
7
6
6.5
6
pH
pH
6
5.5
5
5
5.5
4
4
3
3
0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Sludge fermentation test - ORP Min-sheng sludge
0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
-100
ORP(mV)
ORP(mV)
-100
Tong-yi sludge
0
-200
-300 -300
-200
-300 -300
-400
-400 0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
-350
100
Sludge fermentation test –
Zeta potential
Min-sheng sludge
0
Tong-yi sludge
0
-12 -10
Zeta potential(mV)
Zeta potential(mV)
-10
-20
-18 Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
-30
-20 -20
-30
Original Sonicated Acidified -32 Pasteurized Frozen/thawed BESA-inhibited
-40
-40
0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Sludge fermentation test –
Particle size distribution Min-sheng sludge
400
Tong-yi sludge
1200
350
1000 300
800
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
df,avg(µm)
df,avg(µm)
250
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
200
150
600
400
70
100
90
200 50
35
0
0
25
50
Time (hours)
75
0 100
0
25
50
Time (hours)
75
40
100
Filtrate fermentation test - COD Min-sheng filtrate
Tong-yi filtrate
1.0
1.0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
0.6
0.8
SCOD/COD0
SCOD/COD0
0.8
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
0.4
0.6
0.4
0.2
0.2
0.0
0.0 0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Filtrate fermentation test –
Hydrogen production
Tong-yi filtrate
60
60
50
50
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
40
Yield of hydrogen(mg/g-CODi)
Yield of hydrogen(mg/g-CODi)
Min-sheng filtrate
30
20
10
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
40
30
20
10
0
0 0
8hr
25
50
24hrTime (hours)
75
100
0
8hr
25
50
24hrTime (hours)
75
100
Filtrate fermentation test –
pH measuring
Min-sheng filtrate
Tong-yi filtrate
9
9
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
8
8
6
7
pH
pH
7
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
6
5
6.8
6
6
5
5.5 4
4
3
3 0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Filtrate fermentation test –
ORP
Min-sheng filtrate
Tong-yi filtrate
100
100
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
0
-100
ORP(mV)
ORP(mV)
0
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
-200
-100
-200
-300
-300 -300
-300
-400
0
25
50
Time (hours)
75
-350
-400 100
0
25
50
Time (hours)
75
-360
100
Filtrate fermentation test – Zeta potential Min-sheng filtrate
Tong-yi filtrate
0
0
-5
-5
-12 -10
Zeta potential(mV)
Zeta potential(mV)
-10
-15
-15 -20
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
-25
-30
-18
-15
-20
-25
Original Sonicated Acidified Pasteurized Frozen/thawed BESA-inhibited
-30
-35
-35
-24
-40
-40
0
25
50
Time (hours)
75
100
0
25
50
Time (hours)
75
100
Clostridium inoculum 產氫不增不減
產氫氣
氫氣不增不減
Clostridium sp. C-2
C-3 0
8
16
24 32
40
48
72 96 120 144 168 192 216 240
So… All pretreatments can assist hydrolysis of organic materials effectively. But not all of them help in producing hydrogen. The production of hydrogen increases markedly over 8-24 hr, and is consumed afterward. Freezing-thawing, pasteurization, and acidification assist hydrogen production. But adding BESA and ultrasonication retard it. Hydrogen production reaction occurs in liquid phase, while the existence of sludge would in some sense consumes the hydrogen.
Co-Production of H2 and CH4
H2 Filtrate
Sludge
Pretreatment
Filter
Hydrogen Fermenter
Cake
CH4
Methane Digester
Twin Fermentors
K8 inoculum 產 氫
消耗氫氣 累積甲烷
0 8 16 24 32 40 48 72 96 120 144 168 192 216
K8 240hr 厭氧消化
Clostridium
96hr 厭氧消化
K8
至240hr 厭氧消化
Co-Production
H2
CH4 140
1.4
sludge sludge+clo frozen/thawed acidified alkalized
1.2 1.0 0.8 0.6 0.4
100
original sludge sludge+clostridium frozen/thawed acidified alkalized
80
60
40
20
0.2
0.0 0
120
yield of CH4 (g/kg DS)
Hydrogen content(g/kg DS)
1.6
100
200
Time(hrs)
300
400
0 0
100
200
Time(hrs)
300
400
TCOD
SCOD
12000
10000
TCOD(mg/L)
11000
10000
9000
8000
sludge sludge+clo frozen/thawed acidified alkalized noodle
8000
SCOD(mg/L)
sludge sludge+clo frozen/thawed acidified Alkalized noodle
6000
4000
2000
7000
6000
0
0
100
200
Time(hrs)
300
400
0
100
200
Time(hrs)
300
400
300
NH3-N(ppm)
250
200
150 original sludge sludge+clo freeze/thawed +clo acidified+clo alkalized+clo alkalized noodle+clo
100
50
0
0
100
200
Time(hrs)
300
400
frozen/thawed Fre/thaw
Basified sludge Alkalized
1200
1000
lactic acid acetic acid propionic acid butyric acid
1000
800
800
lactic acid acetic acid propionic acid butyric acid
ppm
ppm
600 600
400 400
200
200
0
0 0
100
200
300
400
sludge+clo Time(hrs) Ori+clo lactic acid acetic acid propionic acid butyric acid
ppm
600
400
200
0 0
100
200
Time(hrs)
100
200
300
Time(hrs)
1000
800
0
300
400
400
500
600
Acidified Acidified
original sludge Original 400
2000 1800
lactic acid acetic acid propionic acid butyric acid
1600 1400
lactic acid acetic acid propionic acid
300
ppm
ppm
1200 1000
200
800 600
100 400 200
0
0 0
100
200
Time(hrs)
300
400
0
100
200
Time(hrs)
300
400
K8 0
8 16 24 32 40 48 72 96 120 144 168 192 216
K8
Methane (g/kg DS)
4
3
2
1
0 0
100
200
300
Time(hrs)
400
500
Original sludge 70
Original
Methane (g/kg DS)
60
50
40
30
20
10
0 0
100
200
300
400
500
Time(hrs)
0
8
16 24
32 40 48
72 96 120 144 168 192 216
SUMMARY
pH 5-6
pH 7-8