innovative biological proceses hallvard...
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NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
INNOVATIVE BIOLOGICAL PROCESES
Hallvard Ødegaard
NTNU/XUAT Postgraduate course 21.05.02-31.05.02: Wastewater as a resource
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
1. In plants with suspendedbiomass, the activatedsludge process, themicroorganisma areflocculated in suspendedflocs. Recirculation ofsludge is needed
2. In plants with attachedbiomass (biofilm) the microsare growing on a fixed surfaceNo recirculation is needed
THE PRINCIPLES OF BIOLOGICAL TREATMENT
OF WASTEWATER
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
IMPORTANT DIFFERENCES BETWEEN ACTIVATED SLUDGE PROCESSES AND
BIOFILM PROCESSES
• Higher active biomass per unit volume in biofilm reactors
• More specialised biomass per unit volume in biofilm reactors
• Sludge concentratioN in biofilm reactor oulet far lower in biofilmreactors
• Biofilm reactors are independent of sludge separation reactordownstream
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
COMPACT, COVERED, HIGH-TECH TREATMENT PLANTS WILL BE ASKEDFOR IN THE FUTURE
There might be a change from activated sludge processestowards biofilm processes
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
THE REASON FOR THE GROWING INTEREST IN BIOFILM REACTORS
1. Less space required
2. Final result less dependent upon biomass separation
3. More specialised biomass at a given point in reactor train
Bio Sep Bio Sep
3.000-5.000 mg/l 100-150 mg/l
Activated sludge system Biofilm system
C,N,DN C,N,DN C,N,DN C N DN
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
BIOFILM PROCESSES ARE GOVERNED BY DIFFUSION
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
DIFFERENT TYPES OF BIOFILM REACTORS
Rislefilter Biorotor Moving bed
Stasjonærtdykket filter
Granulærtdykket filter
Fluidized bed
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
TRADITIONAL BIOFILM PLANTS
TRICKLING FILTER
ROTATING BIOLOGICAL CONTACTOR (RBC)
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
SUBMERGED BIOFILTER PLANT
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
THE MOVING BED BIOFILM PROCESS(The Kaldnes-process)
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
THE PRINCIPLE OF THE MOVING BED REACTOR
Aerobic reactor Anaerobic/anoxic reactor
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
CHARACTERISTICS OF THE BIOFILM CARRIERS
Biofilm carrier :Material : Polyethylene (density 0,95 g/cm3)Size : K1 - Diam./Length = 10mm/7mm
K2 - Diam./Length = 15mm/15mm
K1
K2Surface area K1 K2
Per carrier (mm2) Total Effective for biofilm growth
670490
23001530
Specific area (m2/m3) Total at 70 % carrier filling Effective for biofilm growth
490350
330220
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
THE K2 CARRIER WITH BIOFILM
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
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TYPICAL MOVING BEDPROCESSES FOR
DIFFERENT APPLICATIONS
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
BOD/COD removal
BOD/COD removal only
BOD/COD-removal combined with P-removal
High-rate pre-treatment for upgrading of activated sludge plants
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NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
Substrate loading rate [kg/m3*d]
Sub
stra
te re
mov
al ra
te
[kg/
m3 *d
]
1 2 3
a. Specific area: 1<2<3
Substrate loading rate [kg/m2*d]
Sub
stra
te re
mov
al ra
te
[kg/
m2 *d
]
1 2 3
b. Specific area: 1<2<3
COMPARISON BETWEEN THREE CARRIERS WITH DIFFERENT SPECIFIC SURFACE AREA [r = rmax
. L/(K+L)]
At low loading rates, the difference in volumetric substrate removal rate seem to be small. This is hypothesized to be caused by the fact that carriers with lower specific area have higher biomass load. Comparisons should, therefore, be made based on effective surface area rates
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
Line 1KMT
Line 2AWT
Line 3ANOX
Storagetank
S
S
S
S
S
S
Inletchamber
S
Aeratedbioreactors
S = sampling
Sludge
Sludge
Sludge
Settlingtanks
KMT- K1 KMT- K2
AWT ANOX
Carriers usedPilot plant
Specific surface area KMT carrier K1 KMT carrier K2 AWT carrier ANOX carrier
Estimated surface area[mm2/piece]
total : 670effective : 490
total : 3465effective : 1910
total : 2200effective : 1500
total : 10000effective : 7700
Bulk carriers [number/litre] 1030 159 203 24Specific surface area[m2/m3]
total : 690effective : 500
total : 550effective : 315
total : 450effective : 310
total : 240effective : 190
Carrier characteristics
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
REMOVAL RATES VERSUS LOADING RATES FOR FILTERED COD (SCOD) IN PERIOD 1
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
0,0 2,0 4,0 6,0
Filtered COD loading rate [kg SCOD/m3*d]
Filte
red
CO
D re
mov
al ra
te[k
g S
CO
D/m
3 *d]
KMT AWT ANOXy=0.79x-1.00 y=0.72x-0.77 y=0.66x-0.78
0
5
10
15
20
25
30
0 10 20 30 40 50
Filtered COD loading rate [g SCOD/m2*d]
Filte
rd C
OD
rem
oval
rate
[g S
CO
D/m
2 *d]
KMT AWT ANOXy=0.79x-3.30 y=0.72x-4.17 y=0.66x-6.95
When presented in terms of volumetricrates, the performance seems to beclose to equal at low loading rates
When presented in terms of effectivearea rates, the loading at a given flow is shown to be higher for the low ss carriers
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
0
5
10
15
20
25
30
35
40
45
50
0 20 40 60 80 100
Filtered COD loading rate [g SCOD/m2*d]
Filte
red
CO
D re
mov
al ra
te [g
SC
OD
/m2 *d
]
KMTAWTANOX
100 % removal
0
5
10
15
20
25
30
35
40
0 50 100 150 200 250 300 350
Bulk filtered COD concentration (g SCOD/m3)Fi
ltere
d C
OD
rem
oval
rate
(g S
CO
D/m
2 *d)
KMT
AWT
ANOX
COMPARISONS OF CARRIERS WITH RESPECT TO EFFECTIVE SURFACE AREA REMOVAL RATE OF SCOD
Versus loading rate - period 2All reactors same carrier area
Versus bulk concentration All data from period 1 and 2
Max rate ~ 30 g SCOD/m2.dAvailability of BSCOD limiting up to
a loading of around 50-60 g SCOD/m2.d
1. order at low concentrationsClose to { 1/2 order up to about 200 mg/l
0 order at high concentrations
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
0
5
10
15
20
25
30
35
40
0 20 40 60 80
Filtered COD loading rate [g SCOD/m2*d]
Filte
red
CO
D re
mov
al ra
te
[g S
CO
D/m
2 *d]
KMTAWTANOX
0
2
4
6
8
10
12
14
0 10 20 30 40 50
Filtered COD loading rate [g SCOD/m2*d]
Filte
red
CO
D re
mov
al ra
te
[g S
CO
D/m
2 *d]
K1-375 minK2-375 minK1-52 minK2-52 minK1-27 minK2-27 min
SCOD REMOVAL RATES VERSUS LOADING RATESFirst part of experiments
Same residence time in all reactors
The fact that all carriers are following thesame line, is evidence of the fact that eff. surface
area is the key design parameter.Shape and size of carrier are of minor importance at same eff. surface area
Second part of experimentsVariations in residence time
Again small differences between carriers. Small differences between
various residence times. Note, higher slope of curve at long RT (375 min)Reason : More extensive hydrolysis
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
0
20
40
60
80
100
120
140
0 50 100 150 200
Tot COD loading rate (g COD/m2*d)
Obt
aina
ble
rem
oval
rate
(g
CO
D/m
2 *d
KMT
AWT
ANOX
100 % removal
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120
Tot COD loading rate (g COD/m2d)
Obt
aina
ble
rem
oval
rate
(g
CO
D/m
2 d)
K1-400 min
K2-400 min
K1-50 min
K2-50 min
K1-30 min
K2-30 min
100 % removal
“OBTAINABLE” REMOVAL RATE VS TOT COD LOAD RATEFirst part of experiments Second part of experiments
”Obtainable" COD removal rate : (CODinfluent-SCODeffluent)*Q/ADemonstrates removal rate of tot. COD if all particles > 1 µm were removed
Very high loading rates can be used (> 100 g COD/m2.d) without loosing much on removal rate if biomass can efficiently be removed.
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
DISCUSSION AND CONCLUSIONS
1. It is clear that the MBBR should be designed according to effective surface area loading rate and that comparisons between carriers must be based on this
2. At low loading rates, an effect of hydrolysis of slowly biodegradable organic matter can be expected resulting in an influence of residence time
3. At high loading rates and low residence times (< 60 min) little hydrolysis willoccur. Particles will pass through the reactor more or less “untouched” while the easily biodegradable, soluble organic matter is degraded very rapidly.
4. To take the full advantage of the MBBR for COD removal, one may, therefore, use high loading rates (> 30 g SCOD/m2.d or 100 g COD/m2.d) , resulting in very compact reactors, provided that an enhanced biomass separation method is useddownstream, i.e. coagulation by cationic polymer or metal salts (if P removal).
Chem.
Pretreatm.
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
TotalCOD
SuspendedCOD
ColloidalCOD
SolubleCOD
350
225
50
75
60
70
9510
75
40
6020
15010
40
70
90
190
70
Inert
Biomass
FatCarbohydrates
Proteins
Humics
VFA
F, C, P.
NBD
NBD
SBD
NBDSBD
EBD
SBD
EBD
NBD NBD
SBD
EBD BM
NBD
SBD70
50
50
15
1035
150
70
80
10
100
25
351050
95}275
35
79% of 350
suspended
10% of 350
soluble
NBD-non biodegrabable, SBD-slowly biodegradable, EBD-easy biodegradable
A CONCEPTUAL MODEL OF COD-CONVERSIONIN A MOVING BED BIOFILM REACTOR
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
Air Water Biofilm Support material
Deg
rada
tion
prod
ucts
oxid
ation
Deg
rada
tion
Organic particle
Zone of oxygen shortage
Dissolvedorganics
Possible effect of an adsorbed organic particle on the biofilm surface.
POSSIBLE EFFECT OF AN ADSORBED ORGANIC PARTICLE ON THE BIOFILM SURFACE
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
MOVING BED PROCESSES IN COMBINATIONWITH COAGULATION
The facts that: • the biofilm is primarily active in biodegradation of readily biodegradable
soluble organic matter • the particles pass through the reactor more or less unchanged
make it natural to combine the MBBR (for the removal of soluble matter) with coagulation (for the removal of particles) according to two main principles :
1. Post-coagulation - Particles are allowed to enter the MBBR, pass through it, and removed downstream by coagulation together with biomassEspecially suitable in high-rate plants for COD- and SS-removal only
2. Pre-coagulation - Particles are removed ahead of the MBBR, thus reducing the organic load on this Especially suitable in low-rate plants for nutrient removal
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
HIGH-RATE MBBR IN POST-COAGULATION MODE
05
101520253035404550
0 20 40 60 80 100Filtered COD loading rate [g SCOD/m2*d]
Filte
red
CO
D re
mov
al ra
te
[g S
CO
D/m
2 *d]
K1 K2 100%0
20
40
60
80
100
120
140
0 50 100 150 200Total COD loading rate [g COD/m2*d]
Obt
aina
ble
rem
oval
rate
(C
OD
in-S
CO
Dou
t) [g
/m2 *d
]K1 K2 100%
Chem.
Pre-treatm.
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
HIGH-RATE MBBR IN POST- COAGULATION MODE
Very high loading rates can be accepted - up to 100 g COD/m2d if all particles/biomass is removed downstream. However, settleability strongly dependent upon organic loading :
0 %
20 %
40 %
60 %
80 %
100 %
0 20 40 60
Bioreactor loading rate, g COD/m2d
SS
-rem
oval
in s
ettli
ng ta
nk (%
) K1,v=0,05 m/h
K1,v=0,35 m/h
K1,v=0,65 m/h
0 %
20 %
40 %
60 %
80 %
100 %
0 10 20 30 40
Bioreactor loading rate, g SCOD/m2dS
S-re
mov
al in
set
tling
tank
(%) K1,v=0,05 m/h
K1,v=0,35 m/h
K1,v=0,65 m/h
CONSEQUENCE : Settling should be enhanced by coagulation
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
REMOVAL OF SS IN HIGH RATE MBBR EFFLUENT
0 %10 %20 %30 %40 %50 %60 %70 %80 %90 %
100 %
0,0 0,1 0,2 0,3 0,4
Dose of coagulant [mmol Me/l]
Rem
oval
of S
S
PAX XL 60FeCl3
0 %10 %20 %30 %40 %50 %60 %70 %80 %90 %
100 %
0 1 2 3 4 5 6 7
Dose of polymer [mg/l]
Rem
oval
of S
S
Zetag 67, Medium chargeZetag 75, Medium-high charge Zetag 78, High charge
a. Addition of inorganic metal salts b. Addition of cross-linked (25 %), (PAX - prepolymerised AlCl3) high MW cationic polymer
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
BOD/COD removal in comb. with P-removalTreatment results from two Norwegian plants
Steinsholt treatment plant Eidsfoss treatment plantParameterIn, mg/l Out, mg/l % removal In, mg/l Out, mg/l % removal
BOD – avemax
min
3981720120
10385
97,499,793,5
771 (LOC)18232
6,31 (LOC)9,84,2
91,81 (LOC)94,483,6
COD – avemaxmin
8332760190
4613030
94,498,483,2
- - -
Tot P – avemaxmin
7,112,04,0
0,300,720,12
95,898,892.6
9,827,54,4
0,170,940,03
98,299,888,3
SS - avemaxmin
- 21308
- - 11275
-
1 These values are based on soluble organic carbon (LOC)
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
High-rate pretreatment for upgrading ofactivated sludge plants
Results from solids contact process testing in New Zealand��� ����
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NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
NITRIFICATION
Nitrification after pre-coagulation
Nitrification aftercarbonaceous removal
Post-nitrification afteractivated sludge plant
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NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
NITRIFICATION
2.5
2.0
1.5
1.0
0.5
0.00 2 4 6 8 10
a)
Am
mon
ia re
mov
al ra
teg
NH
4-N/m
2 d
Oxygen concentration, mg O2/l
2.5
2.0
1.5
1.0
0.5
0.00
b)
Ammonium concentration, mg NH4-N/lN
itrifi
catio
n ra
te,
g N
H4-N
/m2 d
DO=9mg/l
DO=6mg/l
DO=3mg/l
0.4g BOD7/m2d
Organic load=0.0g BOD7/m
2 d
1.0
2.0
3.0
4.0
5.0
6.0
7.0
1 2 3 4
Three factors determine the nitrification rate :1. The load of organic matter2. The ammonium concentration (< 3 mg NH4-N/l)3. The oxygen concentration
NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
NITROGEN REMOVAL
Pre-denitrification
Post-denitrification
Post-denitrification afternitrifying activated sludge plant
Combined pre- and post-denitrification
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NTNU - Norwegian University of Science and TechnologyDep. Hydraulic and Environmental Engineering
Prof. Hallvard Ødegaard
CONCLUSIONS
1. The development of the Kaldnes moving bed biofilm process is anexcellent example of fruitful co-operation between university and industry. The reactor have been developed from idea to being wellestablished in the market-place within a time span of 10 years
2. The reactor has proven useful in all applications of wastewatertreatment where a biological process is needed.
3. It gives a very compact bioreactor and offers great flexibility inuse that makes the process very useful when upgrading activatedsludge plants .