Biofiltration: principles, biofilter types and designkenanaonline.com/files/0095/95813/2.5. BIOFILTRATION PRINCPLES... · Biofiltration: principles, biofilter types and design Ep

Biofiltration: principles, biofilter types

and design

Biofiltration: principles, biofilter types

and design

Ep Eding

Aquaculture and Fisheries Group

Wageningen University

The Netherlands

PRESENTATION LAYOUT

1. INTRODUCTION

2. BASIC PRINCIPLES

3. FACTORS AFFECTING THE BIOFILM

4. BIOFILTER DESIGN

1. Production plan (maximum carrying capacity)2. Waste production calculations (in g/kg feed)3. Diurnal variation in waste production4. Water quality limits (Climit)5. Suspended Solids control 6. Biofiltration (principles and design)7. Gas control 8. Denitrification9. RAS design concept (Qrec., Qe etc.)10. Heat (energy) balance model

INTRODUCTION

Filter questions: - Type of biofilter?- Size of the reactor?- Biofilter media?- Which processes are combined?- Kinetics of substrate elimination?

Effect of :-Organic material-TAN -Oxygen- pH - HSL-Temperature

INTRODUCTION

( Eding et al., 2006. Aqaucultural Engineering 34, 234-260).

INTRODUCTION

++ ++→++ 422291918 8185.17 NHOHCOHONOHC

−+ +++→+ 322291918 9185.19 NOHOHCOONOHC

microbiological oxygen consumption: 1.42 kg O2/kg organic matter

microbiological oxygen consumption: 1.59 kg O2/kg organic matter

Without nitrification

With nitrification (autotrophic)

1. Aerobic heterotrophic conversions

(Henze et al., 1997)

BASIC PRINCIPLES

−− →+ 322 2

1NOONO

+−+ ++→+ HOHNOONH 22

32224

2. Nitrite Oxy. Bacteria

1. Ammonia Oxy. Bacteria

+−+ ++→+ HOHNOONH 22 2324 4.57 kg O2/kg NO3--N

BASIC PRINCIPLES

2. Reaction by nitrification

(After Henze, 1997. In Waste water treatment: Biological and Chemical processes, Springer Verlag)

OHHNOHCNONHCO 2275242 4233101315 +++→+ +−+

2 Nitrite Oxydizing Bacteria (NOB)

1. Ammonia Oxydizing Bactieria (AOB)

BASIC PRINCIPLES

2. Reaction by nitrification Growth

+−−+ ++→+++ HNOHCNOOHNONHCO 27532242 102105


O1.04HCO1.88H-0.98NONOH0.020C

1.98HCO1.86ONH

2323275

324

+++

→−+++

BASIC PRINCIPLES


2. Reaction by nitrification

- ( 1.86 O2 *32)/1.00 NH4+-N*14) = 4.25gO2 / gNH4

+-N- ( 1.86 O2 *32)/0.98 NO3

- -N*14) = 4.34gO2 / gNO3- -N

- ( 2.00 O2 *32)/1.00 NO3- -N*14) = 4.57gO2 / gNO3

-- N

O1.04HCO1.88H-0.98NONOH0.020C

1.98HCO1.86ONH

2323275

324

+++

→−+++

N mol / alkalinity Eqv 2n destructio Alkalinity ±=

NaHCO3 83 g/eqv

CaCO3 50 g/eqv

BASIC PRINCIPLES


3. Alkalinity destruction

BASIC PRINCIPLES

CONSUMES STOICHIOMETRY COrganic CInorganic N

(per gN) (g) (g) (g)

NH4+-N 1 g N -------- -------- 1

Alkalinity 1) 7.07 g Alk. -------- 1.70 -------

Oxygen 4.25 g O2 -------- -------- --------

YIELDS

VSS A. bacteria 0.16 g VSS 0.086 -------- 0.02

NO3-N 0.98 g NO3-N -------- -------- 0.98

CO2 5.91 g CO2 -------- 1.61 --------

(After Henze, 1997. In Waste water treatment: Biological and Chemical processes, Springer Verlag).

1) Expressed as CaCO3 equivalents

Reaction by nitrification

Reaction

CARRIERBIOFILMBULK LIQUID

Transport substrates diffusion

Concentration in water

Transport products diffusion

Inert matrix

BIOFILM MODEL


Effect of TAN limitationBIOFILM MODEL

SOXYGEN


Inert matrix

x=0 x=L

STAN

STAN=0

L = biofilm depth

(After Henze, 1997. In Waste water treatment: Biological and Chemical processes, Springer Verlag).

SO2=0

x1


Effect of oxygen limitationBIOFILM MODEL


Inert matrix

x=0 x=L L = biofilm depth

SOXYGEN

STAN

STAN=0

SO2=0

x1

½-order/o-order model

(After Harremoës, 1978. Water pollution microbiology, Wiley, New York)

Effect of oxygen and TAN concentrationBIOFILM MODEL

(After Eding et al., 2006. Aquacult. Eng. 34, 234-260)

BIOFILM MODEL

a CO2 = x1

b2 b1 CO2 = x2

b1 CO2 = x3

x1 > x2 > x3

b1

a


(After Harremoës, 1978. Water pollution microbiology, Wiley, New York)

BIOFILM MODEL

a. O2 and NH4-N, both high, number of nitrifying bacteria limits the reaction

a High oxygen and high ammonium

b. At low concentrations of one of the substrates the reaction rate is diffusion limited

b1 Low oxygen

b2 Low ammonium

reaction)order -(1/2 2OCr =

reaction)order -(1/2 TANCr =

reaction)order -(oconstant == MAXrr


(Bovendeur et al., 1987. Aquaculture 63, 329-353)

BIOFILM MODEL

Concentration ratio at which change of limiting substrate C*

O2 / C*NH4-N is constant 3.6± 0.8

C*O2 / C*NH4-N < 3.6 O2 limiting substrate

C*O2 / C*NH4-N > 3.6 NH4-N limiting substrate

4 type of bio-reactor performances

1. 0 - order removal kinetics in relation to CNH4-N : CNH4-N > C*NH4-N

2. ½ - order removal kinetics in relation to CNH4-N : CNH4-N < C*NH4-N

3. 0 - order and ½ - order removal kinetics in relation to CNH4-N4. ½ - order removal kinetics in relation to CO2 : CO2< C*

O2


BIOFILM MODEL Effect of pH

pH

Bulk fluid

(g/m3)

Effect on nitrification Reference

5.5

5.6

6.5$6.7

7.2 $ 8.8

7.2 $ 9.0

No nitrification

No nitrification

No nitrification

Optimum AOB

Optimum NOB

(Wheaton, 1994)

(Kruner and Rosenthal 1989)

(Boller et al., 1994)

(Chen et al.,2006)

(Chen et al.,2006)

(Eding et al., 2006. Aquacult. Eng. 34, 234-260).

5 6 7 8 9

pH

0.00

0.20

0.40

0.60

0.80

1.00r (g TAN m -2d-1)

Effect of pH

(After Bovendeur, 1989 in Eding et al., 2006 Aquacult. Eng. 34, 234-260).

g NH4-N/m3

r TAN (g/m2/day)

r *

Trickling filter

Effect of pHBIOFILM MODEL

BIOFILM MODEL Effect of pH

Optimal pH can be determined by three effects:

� Activation and deactivation of nitrifying bacteria

� Nutritional effect

� Inhibition through free ammonia and free nitrous acid

Nitrification: 1 g TAN oxidized � consumes 7.1 g CaCO3 .

BIOFILM MODEL Effect of Alkalinity

Alkalinity

(g/m3)

Effect on nitrification Reference

< 35

< 40

> 45

75 $100

Reduced

Reduced

Minimum

Maximum

(Swerinski et al., 1986)

(Chen et al., 1989)

(Biesterfeld et al., 2003)

(Gujer and Boller, 1986)

(Eding et al., 2006. Aquacult. Eng. 34, 234-260).

0 10 20 30

COD removal rate (g m -2d-2)

0.00

0.20

0.40

0.60

0.80

1.000-order NH 4-N removal rate (g m -2d-1)

(After Bovendeur,1989)

r (gTAN/m2/day) = -0.015 * COD (g/m2/d) + 0.65

r TAN (g/m2/day)

r *

g NH4-N/m3

Effect short term loading org. matter (3-4 hr)BIOFILM MODEL

(After Bovendeur, 1989. Dissertation Wageningen University , The Netherlands).

Effect of influent COD/N ratioEffect of influent COD/N ratioBIOFILM MODEL

After: Metcalf and Eddy (2003)

0

0,5

1

1,5

2

2,5

3

0 5 10 15

Influent COD/N ratio

Nitrifica

tion rat

e (g

/m2 /d

ay)

(After Chen et al., 2006. Aquacult. Eng. 34, 179-197.

FLOATING BEAD FILTERT= 20°CChemically fed reactorSucrose as organic carbon sourceTAN concentration 10 mg/L

Heterotrophic bacteria effectHeterotrophic bacteria effectBIOFILM MODEL

(From Dr. J.P. Blancheton, IFREMER, FRANCE) )

Effect of particulate organic matterEffect of particulate organic matterBIOFILM MODEL

(After Chen et al., 2006. Aquacult. Eng.34, 179-197)

0

20

40

60

80

100

0 20 40 60

Particulate Organic Matter (mg/L)

% N

itri

fica

tion E

ffic

inec

y

Mineral packing media BIOGROGSubmerged filterParticles from particle separator rearing system

Effect of temperature

Study based on a Biodrum and no organic matter (BOD) supply

Prediction of relative nitrification rates ( for range 7-35°C)

BIODRUM At 15 °C a 24 % reduction is obtained of rates at 25°C

(Wortman and Wheaton, 1991. Aquacult. Eng. 10, 183-205.)

-

Comparison two pilot scale biofilters, temperature activity coefficient 1.08 van’t Hoff –Arhenius like equation

TRICKLING FILTERrTAN = 0.55 g/m2/day (25 °C) African catfishrTAN = 0.25 g/m2/day (15 °C) Rainbow Trout

Aquaculture 63 (1987) 329-353 (Bovendeur et al., 1987. Aquaculture 63, 329-353)

BIOFILM MODEL

Effect of temperature

Study based on Submerged filter, internal aeration, no organic matter (BOD) supply)

From 20°C -27°C: - 1.108 % increase per °C increment (under O2 limitation conditions)

- 4.275% increase per °C increment (under TAN limitation conditions)

(Zhu and Chen, 2002. Aquacult Eng. 26 221-237)

BIOFILM MODEL

Studies predict different temperature effects on TAN removal rate

Effect of salinityBIOFILM MODEL

(After Nijhof and Bovendeur, 1989. Aquaculture 87, 133-143)

After Bovendeur, 1989)

0 1 2 3 4 5 6 7 8

NH4 -N concentration (g m-3)

0.00

0.20

0.40

0.60

0.80

1.00NH4 -N removal rate (g m -2d -1)

EFFECT SEAWATER (24°C)

Seawater (pH = 8.3; 7 g O2 m -3 )

C*FC*S

Freshwater (pH = 8.2; 8.4 g O2 m-3 )

BIOFILM MODEL Effect of hydraulic surface load

After Eding, 2006. Aquacultural Engineering 34, 234-260

(Ater Kamstra et al., 1998 . Aquacult. Eng. 17, 175-192).

Effect of hydraulic surface loadBIOFILM MODEL

Hypothetical Biofilm (trickling filter)

Removal rate(g TAN m-2d-1)

Start up

TAN concentration (g m-3)

‘Full grown’ biofilm

NO2-N concentration (g m-3)

‘Full grown’ biofilm

Start up

Removal rate(g NO2-N m-2d-1)

Effect of ageingBIOFILM MODEL

Trickling filter biofilm

(After Bovendeur, 1989 . Dissertation Wageningen University , The Netherlands).

BIOFILM MODEL Effect of Nitrite

CARRIERBulk fluid BIOFILM

TAN

Nitritification

NO2--N

Nitratification

NO3--N

(Based on Brett and Zala, 1975). ( After Nijhof and Klapwijk, 1995. Water Res. 29, 2287-2292)

N-excretion (mg)

Feeding

0 8 16 24

Time (h)

TAN

1

2

BIOFILM MODEL Effect of management

- Feeding and feed composition- Harvesting & grading & restocking- Continuous water treatment processes

(Bovendeur et al., 1987. Aquaculture 63, 329-353)

BIOFILTER DESIGN Safety factor

1

r TAN (g/m2/day)

rMax.*

g TAN/m3

r2

r3

1. Low safety factor

2. Intermediate safety factor

3. High safety factor

PTAN(g TAN)

Feeding

r TAN (g/m2/day)

Metabolism limitation

Waste production dynamics Waste removal kinetics

rd *

0 24 Hours g NH4-N/m3

Peak

Effect of diurnal variationBIOFILTER DESIGN

1. Low safety factor

Heinsbroek and Kamstra, 1990. Aquacult. Eng. 9, 187-207)(Bovendeur et al.,1987. Aquaculture 63,329-353;

PTAN(g TAN)Feeding r TAN (g/m2/day)



rd*


Peak


2. Intermediate safety factorrp

Heinsbroek and Kamstra, 1990. Aquacult. Eng 9, 187-207)(Bovendeur et al.,1987. Aquaculture 63,329-353;

PTAN(g TAN)Feeding

r TAN (g/m2/day)



rd*


Peak


3. High safety factorrp


� Trickling filter� Rotating biological contactors� Bead filter � Moving bed biofilm reactors� Submerged filter� Fluidized bed filter

BIOFILTERS USED IN RAS

(After Eding, 2006. Aquacultural Engineering 34, 234-260.)

African catfish RAS

Crossflow

Filter pac Bionet

Trickling filter

Trickling filter

African catfish RAS

Lamella sedimentation unit

Trickling filter

Fish tanks

Courtesy Fleuren & Nooijen BV, Someren, The Netherlands (http://www.fleuren$nooijen.nl/Home.html)

(From Eding and Schneider, 2005. RAS-Short course, Trondheim)

Trickling filter

(Courtesy Fleuren & Nooijen BV, Someren The Netherlands, (http://www.fleuren$nooijen.nl/Home.html)

Sump

Trickling filter

Lamella sedimentation

Trickling filter

African catfish RASTrickling filter


Trickling filter sizing

Determine:Step 1. Peak feed load (kg feed/day)Step 2. Feed protein content (%)Step 3. Temperature (°C)Step 4. TAN production rate (PTAN = g TAN/day)Step 5. Desired TAN (g/m3) Step 6. In situ nitrification reduction PTANStep 7. Passive denitrification (%)Step 8. Allowable Nitrate-N (g/m3)Step 9. Water exchange for Nitrate-N control reduction PTANStep 10. Treatment Efficiency (TE) (%)

(Losordo and Hobbs, 2000. Aquacult. Eng. 23, 95-102 )

Determine:

Step 10. Flow for TAN (m3/day) control

QTAN = PTAN / ( CTAN,IN – CTAN,OUT)= PTAN / (1-TE/100) x CTAN,OUT

Step 11. Required surface area (A) & filter volume (V)

TAN removal rate (rTAN in g TAN/m2/day)A (m2) = PTAN (g TAN/day) / rTAN (g TAN/m2/day)V (m3) = A (m2) / SSA (m2/m3)


(Losordo and Hobbs, 2000. Aquacult. Eng. 23, 95-102 )


Determine:

Step 13. Cross-sectional filter area (ф in m2) and filter diameter (Ø) Fixed media depth (H in m)

ф (m2) = V (m3) / H (m)Ø (m) = 2 x SQRT(ф (m2) /3.1416)

Fixed: Desired TAN conc., Treatment efficiency, TAN removal rate, Filter height

Trickling filter design

ri = a √ [CTAN,IN]-0.1 (g/m2/day)

a = 7.81*10-4 H * + 0.2 (m/day)

H = hydraulic surface load (m/day)

If CTAN,IN ≥ 2 g/m3

then CTAN,IN= C*TAN = 2 g/m3

(correction for filter media)

Biofilter

QfRTAN

Efficiency ECTAN,IN

CTAN,OUT

CLimit

r*

C*=2 gNH4-N/m3

Eding et al., 2006, Aquacult Eng. 34, 234-260

Determine filter performance

Plug flow modelBiofiltration by trickling filters

Kamstra et al. 1998. Aquacult. Eng. 17, 175-192

Spec. surface area : 150-234 m2/m3

TAN removal rate : 0.1-1.0 gTAN/m2/dayHydraulic surface load : 100-750 m3/m2/dayHeight : 2-4 m

(Bovendeur et al., 1987; Nijhof, 1995; Kamstra et al, 1998)

� Simple design/construction

� Aeration /degassing CO2

� High stability

� Cooling tower in summertime

� No maintenance

� Continuous

� Low volumetric removal rate (g TAN/m3day)

� Large biofilters

� Biofilm sheared off

� Moderate capital costs

� Foam production

� Head loss

Characteristics:

Trickling filters

Surface area: 600 ft2

Surface density: 92 ft2/ft3

Rotation: Air injection or water injectionRotation velocity: 2-3 rpmSupport rack: PVCFloor space: 12 ft2 (with staging unit)

RBC-600, RBC-10000,

Rotating biological contactor (RBC)

(Fresh-Culture System Inc., Breinigsville, USA Website: www.fresh-culture.com)

Air or water driven

(Fresh-Culture System Inc., Breinigsville, USA . Website: www.fresh-culture.com)

Air or water driven RBC’s

Commercial Aquaculture systems using RBC’s

Rotating biological contactor sizing

� Compartimentalization: specialization bacteria� Max. hydraulic loading: 300 m3/m2/day � Peripheral velocities: 0.18- 0.39 m/s� Submergence: 40%� Reduction in CO2 conc.: 39%

(Brazil,2006. Aquacult. Eng. 34, 261-274)


(Brazil,2006. Aquacult. Eng. 34, 261-274.)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1.1 1.3 1.5 1.7 1.9

TAN Loading (g/m2/day)

TA

N r

emo

ved

(g/m

2 /day

)


Brazil,2006. Aquacult. Eng. 34, 261-274.

Van Gorder and Jug-Dujakovic, 2005, Journ. of Rec. Aquaculture, 6: 23-38

Determine:

Step 1. Calculate oxygen requirement (kg O2/day)Step 2. Calculate water flow requirement for DO (L/day)

Check the number of tank exchanges per hour (N/hour)Step 3. Calculate TAN production (kg TAN/day)Step 4. Determine TAN removal rate (g/m2/day) Step 5. Calculate biofilter surface area (A media = m2)

(Timmons and Ebeling, 2007)

Rotating biological contactors

� Passive aeration� Low head loss � Non clogging� Reliable performance� Degassing� Modularization� Low operation costs� Self cleaning

� Relative high purchase price� Mechanically more complex

(e.g. Motor driven types)� Relative high foot print

(See also Wheaton,1994; Timmons and Ebeling 2007)

Characteristics:

A. InletB. Water outletC. Filter chamberD. Buffer area for airE. Air inletF. Air outletG. Funnel in which beads are rinsedH. Sludge collection chamberH. Sludge discharge valveI. Window

Polygeyser

Biofiltration by floating beadfilters

Beadfilter

O2Org. WastesCO2

BOD decay

NH3O2Bicarbonates

NitrateCO2

NO2 Nitrification

Heterotrophic biofilm

After Malone et al., 1998

Embedded nitrifiersPlasticBead

Biofilm carrier: Floating beads

Biofiltration by bead filters

Filtration mode Mixing modePropeller Bead filter


Courtesy Dr. Malone

Sludge removalSettling modePropeller Bead filter


Courtesy Dr. Malone

Fysical filtration Biological filtration

Bead filter

Courtesy Dr.Malone

Courtesy Malone

Propeller Bead filter


Bead filter sizing

Determine:Step 1. System volume (Vs in m3)Step 2. Max. fish load (L in kg)Step 3. Peak feed load (kg feed/day)Step 4. Feed protein content (%)Step 5. Operating temperature (°F)Step 6. Salinity (ppt)Step 7. Determine TAN production /kg feed (ETAN)Step 8. Correct TAN production for feeds with higher protein (P2, %)

ETAN = P2 [(30gTAN/kg feed)/35% protein)]Step 9. Correct for in situ nitrification (Is = 30%)

(Drennan et al., 2006. Aquacult. Eng. 34, 403-416 )

Bead filter sizing

Determine:Step 10. Correction TANTotal for water exchange

TANBiofilter = TANT - (1.5mg/L)(Qexchange(in L/Day) )(10-3)

Step 11. Volume biofilter (Vb in m3)Enhanced filter mediaVBiofilter media= TANBiofilter/530 g TAN/m3 = …m3

Recommended model ……..

Step 12. Flow rate (Q) through biofilter Hydraulic loading rate = 806 L/min./m3 of beadsQ = (806 L/min./m3 beads)(m3 beads)/kg feed = ..L/min/kg feed

(Drennan et al., 2006. Aquacult. Eng. 34, 403-416 )

Characteristics

� Combines solids removal with nitrification

� Fine particle removal � Easy to install and operate� Biofilm management important !

(backwashing frequency) � Modularization

� No degassing� Leaches nutrients � No internal aeration� Head loss

Courtesy Dr.Malone

Propeller Bead filter

Bead filter characteristics

Aquaculture Systems Technologies, (New Orleans, LA, USA)

Moving bed biofilm reactor Biofilm carrier: plastic media

Heavily aeratedFilled to 70% of operating volume

Moving bed biofilter

0,00

0,40

0,80

1,20

1,60

2,00

0,00 0,50 1,00 1,50 2,00

REACTOR EFFLUENT (g TAN/m3)

RTA

N (g

TA

N/m

2 /day

)

TAN removal rate for Kaldness type K1, SSA= 500 m2/m3, 24 °C

(After Drennan et al., 2006. Aquacult. Eng. 34, 403-416)

Moving bed biofilm performance

SUBMERGED BIOFILTERS

4 Biofilters in seriesSchematic overview

Submerged biofilters

Fluidized sand beds Biofilm carrier: Sand

(PrAqua Technologies,

Nanaimo, British Colombia)

Spec. surface area: sand 4000-45000 m2/m3

TAN removal rate- Cold water

: 0.2-0.4 kg/m3 expanded bed/day

- Warm water: 0.6-1.0 kg/m3 expanded bed/day

(Timmons et al, 2001)

Fluidized sandbed filter

Fluidized sand bedsDesign steps:

- Determine the TAN load - Determine the sand volume

Based on TAN removal rate per m3 sand- Select design depth of sandbed- Determine cross-sectional area filterbed - Select a sand size in relation to flow rate- Determine fluidization velocity - Compare flow rates for water quality control in the fish tanks, adjust crossectional area of the bed if necessary

- Check mass balance on oxygen- Design water delivery system

Biofilm carrier: Sand

(For design see Timmons et al, 2001)Q (m3/min)= Fluidization velocity (m/s) x A(m2) x 60 s/min


Fluidized sand bed

- Easier start up

- No pipes and orifices

- 1/3 less pressure

Biofilm carrier: Sand or Plastic media

(Freshwater Institute, Sherperdstown, West Verginia))

(The CycloBio(R))Manufacturer: Marine Biotech


(Artic Charr culture)

Fluidized sand beds

� High specific surface area � Uniformity of buoyancy� Easy media containment � Relative low investments� Sand size is related to temperature� High TAN removal efficiency

� Need for CO2 stripping� Controlled flow � Head loss� Oxygen supply from water� More difficult to operate� Can have maintenance problems� Sand loss

- bed growth management

Characteristics

Biofilm carrier: Sand

Fluidized sandbed characteristics

Questions?Questions?

Aquaculture and Fisheries group (AFI) Wageningen University The Netherlands

E- mail: [email protected]

Aquaculture and Fisheries group (AFI) Wageningen University, The Netherlands

E- mail: [email protected]

Documents

Biofiltration: principles, biofilter types and designkenanaonline.com/files/0095/95813/2.5. BIOFILTRATION PRINCPLES... · Biofiltration: principles, biofilter types and design Ep