Putting the Misconceptions to Rest:
2010 HWEA ConferenceHonolulu, HI
Brandy NussbaumI. Kruger, Inc
Clarification/Separation OPTIONS Following MBBR Treatment
Discussion Topics
• What is MBBR• Conventional Clarification• High Rate Ballasted Clarification• Dissolved Air Flotation• Discfiltration• Granular Media Filtration• Membranes• Summary
Aerobic reactor
The Principle of the Moving Bed Biofilm Reactor (MBBR) Technology
Anoxic reactor
The Moving Bed Biofilm Reactor (MBBR) in Practice
Components to the MBBR Aerobic SystemAnoxKaldnes MediaMedia Retention Sieves• 304L Stainless Steel • Cylindrical Wedge Wire• Perforated Plate foam control sievesAnoxKaldnes Aeration Grid• 304L Stainless Steel • Medium Bubble• Maintenance Free – No replacement parts
Components to the Anoxic MBBR System
AnoxKaldnes MediaMedia Retention Sieves• 304L Stainless Steel • Flat Panel Wedge WireSlow-Speed Mixers• Submersible or Top entry• Can be speed controlled
MBBR Solutions – Highly Flexible
MBBR stand-alone
MBBR as pre-treatment (roughing, BASTM)
MBBR as tertiary treatment(polishing, LagoonGuardTM)
MBBR in activated sludge (HYBASTM/IFAS)
MBBR Biomass Separation Alternatives
MBBR –Actiflo™(ballasted flocculation)
MBBR - settling
MBBR - Flotation
MBBR – Media Filtration
MBBR – Disc Filter
MBBR – Membrane Filtration
Development of PSD’s at various MBBR loadings (HRT’s) (Åhl et al, 2006)
0
2
4
6
8
0,01 0,1 1 10 100 1000particle diameter µm
diff
volu
me%
inlet HRT = 1hHRT = 2hHRT = 3hHRT = 4h
0
2
4
6
8
0,01 0,1 1 10 100 1000particle dimeter [µm]
diff
num
ber%
inletHRT = 1hHRT = 2hHRT = 3hHRT = 4h
1. There is a shift towards a higher volume of largerparticles with increasing HRT
2. There is at the same time,however, a relative increasein the number concentrationof submicron particles withincreasing HRT
Hypothesis :• Flocculation is taking place• Erosion of single bacteria or
remains of dead cells happens• Both are f(loading/HRT)
Relative amounts of COD in the different size fractions (Melin at al, 2005)
Majority of COD in particles > 1 µm
Increase in the suspended COD with increasing HRT
Decrease in colloidal particles (0,1 – 1 µm) when HRT increase
0
10
20
30
40
50
60
70
80
>1 µm 0.1-1 µm 30 kD-0.1 µm <30 kD
Size fraction
Amou
nt o
f CO
D (%
)
HRT = 0.75 h HRT = 1 h HRT = 3 h HRT = 4 h
a)
Conventional Settling after MBBR
Withoutcoagulation
CoagulantCoagulantWith coagulation
• Metal salt (Al, Fe)• Cationic polymer• Low Al/Fe + cat. polymer
• High Al/Fe + anionic polymer
Cheyenne – Crow Creek WWTP
THE CROW CREEK WATER RECLAMATION FACILITY THE CROW CREEK WATER RECLAMATION FACILITY
New Treatment ProcessNew Treatment Process
Screening & Degritting
Discharge
PrimaryClarifier
1
PrimaryClarifier
2
SecondaryClarifier
2
SecondaryClarifier
1UV Disinfection
Flow Split Anoxic
Basins(Pre-Denite)
New MBBR Reactors
Future Nitrate Recycle
Reuse Filters
Alum/Polymer Sludge
PERFORMANCE DATA
0.0
5.0
10.0
15.0
20.0
25.0
0.050.0
100.0150.0200.0250.0300.0350.0400.0450.0500.0
Efflu
ent
Influ
ent
Cheyenne BOPU Crow Creek WRFTSS Removal - 30 Day Avgerage
Inf luent Effluent
Actiflo® Microsand Ballasted Clarification
Hydrocyclon
FlocculationInjectionCoagulation
Polymer
Microsand
Coagulant
Inlet
Lamella--sedimentation
OutletMMMM
Sludge
Hydrocyclon
FlocculationInjectionCoagulation
Polymer
Microsand
Coagulant
Inlet
Lamella--sedimentation
OutletMMMM
Sludge
Water
Primary particles
CoagulantMicrosand Polymer
Flocs
Water
Primary particles
CoagulantMicrosandMicrosand Polymer
Flocs
Polymer
Flocs
South Adams WWTP MBBR-ACTIFLO® Pilot
Influent characteristics
Coagulants and dose Effluent characteristics
Process
Rise rate3
mg SS/l Turb FeCl3 or Als(SO4)3 + anionic polymer1
mg SS/l Turb. mg P/l
MBBR +
ACTIFLO®
55 – 85 m/h
most tests at
65 m/h4
110-150
130-160
12.4 mg Fe/l + 0,8 mg/l
7.6 mg Al/l + 0,6 mg/l
6.2 mg Fe/l + 0,6 mg/l
2.1 mg Fe/l + 0,45 mg/l
3
< 5
5
10
< 2
< 2
0.122
MBBR + Settling +
ACTIFLO®
120 m/h
100 m/h
3,5–4,5
10 - 25
13.2 mg Fe/l + 0,5 mg/l
6.0 mg Al/l + 0,6 mg/l
1.4
< 2
<0,1
>0.3
MBBR + Settling +
ACTIFLO® Turbo
90 m/h
115 m/h
115 m/h
3,5–4,5
10 - 25
13.2 mg Fe/l + 0,5 mg/l
9.6 mg Fe/l + 0,5 mg/l
9.1 mg Al/l + 0,6 mg/l
< 1
1.2
1.4
<0.1
<0.1
0.1
1Anionic polymer M155 2Lowest value achieved - at high Al dose (14.4 mg Al/l) 3Rise rate, hydraulic surface load (m3/m2 . h) calculated on the settler foot-print area
Summary of Pilot Results, Quebec, Can (John Meunier, VWS, Can)
Actiflo following MBBR• MBBR load : 4 – 25 g BOD5/m2d• Actiflo rise rate: 40 – 120 m/h• FeCl3-dose : 30 – 115 µL/L• Polymer dose : 0.5 - 1.2 mg/l
Parameter units Influent Effluent % removal
Total P (mg/L) 1 - 5 0.2 -0.7
Turbidity NTU 58 - 154 2.5 - 6.8
TSS (mg/L) 94 - 196 13 - 24 86 - 88
COD (mg/L) 176 - 361 31 - 58 82 -84
BOD (mg/L) 53 - 155 5 - 11 91 -93
pH --- 7.1 - 7.5
ExampleDrammen WWTP
InletLine 1
Line 2
Line 3
Line 4
Line 5
Line 6
1 2
1: Flocculation2: Sedimentation 3: Thickeners4: Sludge silo
Outlet
3
4
InletLine 1
Line 2
Line 3
Line 4
Line 5
Line 6
11 22
1: Flocculation2: Sedimentation 3: Thickeners4: Sludge silo
Outlet
33
44
Inlet Kaldnes MBBR® 1-1
3
1: Kaldnes MBBR®
2: DAF3: Sludge silo 3% TS4: Sludge silo 6% TS
OutletDAF 1
21
Kaldnes MBBR® 1-2
Kaldnes MBBR® 2-1 Kaldnes MBBR® 2-2
Kaldnes MBBR® 3-1 Kaldnes MBBR® 3-2
Kaldnes MBBR® 4-1 Kaldnes MBBR® 4-2
Kaldnes MBBR® 5-1
Kaldnes MBBR® 6-1
Kaldnes MBBR® 5-2
Kaldnes MBBR® 6-2
DAF 2
4
DAF 3
DAF 4
DAF 5
DAF 6
Inlet Kaldnes MBBR® 1-1
33
1: Kaldnes MBBR®
2: DAF3: Sludge silo 3% TS4: Sludge silo 6% TS
OutletDAF 1
2211
Kaldnes MBBR® 1-2
Kaldnes MBBR® 2-1 Kaldnes MBBR® 2-2
Kaldnes MBBR® 3-1 Kaldnes MBBR® 3-2
Kaldnes MBBR® 4-1 Kaldnes MBBR® 4-2
Kaldnes MBBR® 5-1
Kaldnes MBBR® 6-1
Kaldnes MBBR® 5-2
Kaldnes MBBR® 6-2
DAF 2
44
DAF 3
DAF 4
DAF 5
DAF 6
Inlet
3
4
1: Kaldnes MBBR®
2: Actiflo®
3: Thickeners4: Sludge silos 6%5: Free space (chemical handling)
Outlet
1
Actiflo® 1
Actiflo® 2
25
Kaldnes MBBR® 1-1 Kaldnes MBBR® 1-2
Kaldnes MBBR® 2-1 Kaldnes MBBR® 2-2
Kaldnes MBBR® 3-1
Kaldnes MBBR® 4-1
Kaldnes MBBR® 3-2
Kaldnes MBBR® 4-2
Inlet
33
44
1: Kaldnes MBBR®
2: Actiflo®
3: Thickeners4: Sludge silos 6%5: Free space (chemical handling)
Outlet
11
Actiflo® 1
Actiflo® 2
2255
Kaldnes MBBR® 1-1 Kaldnes MBBR® 1-2
Kaldnes MBBR® 2-1 Kaldnes MBBR® 2-2
Kaldnes MBBR® 3-1
Kaldnes MBBR® 4-1
Kaldnes MBBR® 3-2
Kaldnes MBBR® 4-2
Upgrading a chemically enhanced primary plant to become a secondary plant by the use of MBBR and ACTIFLO®
Two MBBR – ACTIFLO in Bergen Under Construction
Bergen WWTP design:
• rBOD = 11,5 g BOD5/m2d
• vf = 60 m/h(rise rate in settling zone)
0
50
100
150
200
250
300
350
Conc
entra
tion
BOD
5, m
g/L
BOD5 results Handeland WWTP 2007-2008
Influent concentration
Effluent concentration
0
5
10
15
20
25
30
35
40
0
100
200
300
400
500
600
700
800
Out
let c
once
ntra
tion,
g O
/m3
Inle
t con
cent
ratio
n, g
O/m
3
Date
BOD5 results Skreia WWTP 2005-2008
BOD5:Inlet
BOD5:Outlet
a. Handeland WWTP
b. SkreiaWWTP
Handeland, Skreia MBBR/Actiflo® Plants
MBBR-Flotation (DAF)
Historically a very popular option for compact MBBR separation in Scandinavia
Data below from the Johnstown, CO LagoonGaurd MBBR-DAF Installation
Parameter DAF influent Range Average DAF Effluent Range Average
Turbidity, NTU 18-80 40 2-28 15
BOD mg/l 24-35 27 3-13 10
TSS mg/l 19-62 35 8-25 11
Typical design values for DAF following MBBR (Ødegaard et al, 2009)
1052 – 3 m
At maximum design flow, Qmaxdim
At design flow, Qdim
Surface overflow rate (m2/m3.h)Tank depth
1052 – 3 m
At maximum design flow, Qmaxdim
At design flow, Qdim
Surface overflow rate (m2/m3.h)Tank depth
Dispersion pressure : 400 – 600 kPa (4-6 bar)Air saturation: 80 - 90 %Dispersion water flow (% of Qmaxdim) : 10 - 25 %
(depending on SSin and air saturation)
Average Results from three Scandinavian Plants using DAF after MBBR
Parameter Nordre Follo WWTP Gardermoen WWTP Sjölunda WWTP
Design values Design flow (m3/h) Max. flow (m3/h) Temp. (oC)
750 1125 6-14
920
1300 4-14
7920
15840 8-20
Plant size Tot. MBBR vol. (m3) Flocculation vol. (m3) Flotation area (m2)
3710 230 150
5790 180 215
6230 3960 2000
Year documented Average in-out conc. and treatment efficiency SS (mg/l)
BOD (mg/l) COD (mg/l) Tot N (mg/l) Tot P (mg/l)
2008 In Out % - - - 123 3.8 97 453 49 89 32 6.5 80 4.2 0.14 97
2009 In Out % - - - 274 2.2 99 725 33 95 62 8.7 85 8.8 0.11 99
2009 In Out % 282 12 96 231 10 96 559 62 89 41 10 76 5.3 0.30 94
MBBR - Microscreening
The Hydrotech Disc Filter
• Directly after MBBR or for polishing• Sieve openings: 10 – 100 µm• Operational head-loss: 10”• Backwash during operation
Disc Filter plant after post DN MBBR at Rya WWTP,Gothenburg, Sweden
Results from the Rya WWTP Discfilter(Mattson et al, 2009)
0
5
10
15
20
25
30
0 10 20 30 40 50Influent SS (mg/l)
Filtr
atio
n ve
loci
ty (m
/h)
10 micron
18 micron
Filtration rate (based on total filter mesh area) versus influent SS (Persson et al. 2006)
Feed, mg SS/l Effluent, mg SS/l Capacity, m3/m2 filter
. h Mesh pore
size, µm Average St.dev. Average St.dev. Average St.dev.
Number ofSamples
18 27.5 14.5 5.0 1.8 13.7 7.2 37
10 30.5 10.8 3.5 1.3 4.8 2.2 22
Discfilter With Chemical Dosing
0
20
40
60
80
100
120
140
160
180
200
0 50 100 150 200 250 300 350
Efflu
ent S
S (m
g/l)
Influent SS (mg/l)
Gardermoen WWTP 40 micron
Nordre Follo WWTP 40 micron
Gardermoen WWTP 20 micron
Effluent SS versus influent SS without any pre-coagulation/flocculation
0
5
10
15
20
25
30
35
40
45
50
0 10 20 30 40 50 60 70 80 90 100Polymer dose (mg PE/g SS)
Efflu
ent S
S (m
g/l)
Gardermoen WWTPNordre Follo WWTP
Effluent SS as a function of polymer dosing.
Sand filtration after MBBR
Various uses:
As polishing step
Directly after nitrifying or denitrifying MBBR• Ex.: Klagshamn WWTP
8,2 m/h at Qmax
Effluent : < 5 mg SS/l, 0,2 mg P/l
Directly after high-rate (secondary treatment) MBBR-Cheyenne Crow Creek
Membrane filtration after MBBR
Different strategies tested
a.MBBR – submerged hollow fiber UF membrane (i.e. Zenon ZeeWeed)
b.MBBR – Discfilter – Contained hollow fiberUF membrane
c.MBBR – submerged membrane in reactor with settling zone
d.MBBR – DAF – Contained hollow fiber UF membrane
Conclusions
1. Particle size distribution (PSD) of biomass leaving MBBR:a. Large mass fraction of relatively large particles (30 – 300 µm), but
a high number of small particles (0.1 – 1 µm). The easiest way to deal with the latter is by coagulation ahead of the separation reactor
b. The PSD is shifted towards larger particles when the organic area load is decreasing (HRT is increasing). Hence the higher the area load, the better is the effect of pre-coagulation
2. All of the commonly used separation methods may be used.a. MBBR allows the use of a variety of separation methods providing
greater flexibility that the AS processes missb. DAF is well provenc. Microsand ballasted lamella settling (Actiflo) is of increasing
interest and results in an extremely compact plant d. A very compact solution is also achieved with the use of Discfilter
di tl ft th MBBR li hi t ti t
Final Thoughts
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