Transcript Recirculation Aquaculture Why Recirculation • Water use • Environmental impact • Climate • Land • Quality • Disease • Predation • Exotic species (or control thereof…

Recirculation Aquaculture
Why Recirculation
• Water use
• Environmental impact
• Climate
• Land
• Quality
• Disease
• Predation
• Exotic species (or
control thereof…
Cost of Labor : $7/day
Solids Siphon
Near Ensenada, Mexico; 2002
Near Ensenada, Mexico; 2002
Near Ensenada, Mexico; 2002
Raise a lot of fish with Little Labor
Definitions
Recirculating System:
A production system that reconditions water to extend it’s reuse
A technique that increases the value of a limited resource
An artificial well that never ceases to flow
A stable platform forming a reliable base for commercial production
• Five Major Processes
1)
2)
3)
4)
5)
Circulation
Clarification (Solids capture)
Biofiltration (BOD reduction/nitrification)
Aeration (Oxygen replacement)
Degasification (CO2 stripping)
N
DENITRIFICATION
2
NO 2
NO 3-
H
FEED
NITRIFICATION
ION BALANCE
+
GAS STRIPPING
CO 2
ALKALINITY ADDITION
TAN
BOD
BOD REDUCTION
BACTERIA
SOLIDS
O
DISSOLVED
REFRACTORY
MANAGEMENT
2
INERT
SOLIDS
AERATION
O 2
CO
2
SOLIDS REMOVAL
The Five
Major Processes
in a Recirculating
Five Major
Treatment
Objectives
System
Feeding
Circulation
Biofiltration
Fish Tank
Solids Capture
Aeration
Degasification
Return to
Tank
Double Drain at Center of Tank
Inlet
Outlet
Sludge outlet
From Under-drain
Over-Drain Flow
Captured Solids
Microscreen Cleaning Jets
From Microscreen
Micro-Bead Filter
1 mm Styrene Beads
Centrifugal Pumps
Pressure line from Centrifugal
Pumps
Oxygen
Bubbles
02 Flow Meter
Pressure Gauge
Water
Return to Tanks
Solids Capture
Feeding
Circulation
Biofiltration
Fish Tank
Solids Capture
Aeration
Degasification
Solids Capture
Impact of Solids on Recirculating
Systems
• Increased BOD load (organic solids) causes
problems with Biofilters
• Increased system turbidity (fine particles)
• Gill damage in fish (fine particles)
Solids Capture
Particle Size Distribution (microns)
Settleable
10-4
Dissolved
10-3
10-2
10-1
Colloidal
1
10
100
Suspended
Tilapia
No Fine Solids Capture
SOLIDS REMOVAL PROCESSES AND
PARTICLE SIZES
Coarse
Screens
Cartridge Filter
Plain
Sedimentation
Tube Settler
Microscreen
Granular Filter
Foam Fractionation
100
30
75
Particle Size, microns
10
Solids Capture
SEDIMENTATION
Vs
OUTFLOW
Settling Zone
(Vs > Overflow Rate
to settle)
Sludge Zone
Outlet Zone
INFLOW
Inlet Zone
Vh
Solids Capture
Solid Removal Technologies
•
•
•
•
Effective for selected particle size
Differ in headloss…energy $$$
Differ in labor for upkeep
Sensitive to organic loading
Floor Plan
“BYPASS” FILTRATION
TANKS
Pump
Liquid O2
Bead Filter
Packed Column
Fluidized Bed
Packed Column
Lime Addition
“IN-LINE” FILTRATION
TANKS
Shrimp Maturation in South America
Pump
Bead Filter
Fluidized Bed
Packed Column
Feeding
Circulation
Biofiltration
Fish Tank
Solids Capture
Aeration
Degasification
Biofiltration
Types of Biofilters
Biofiltration
H e te ro tro p h ci B oi fm
il
O x ygen
BO D
O rg a n ci W a s te s
D e ca y
C a rb o n D oi x di e
Amm o n ai
O x ygen
P al s t ci
B ead
B ci a rb o n a te s
N itr if ci a t oi n
N itr ite
C a rb o n D oi x di e
N itra te
Em b e d d e d N itr ify ni g
B a c te r ai
Biofiltration
TS S
H e te ro t ro p h ci
BO D
B a c te r ai
TAN
NH
3
+ NH
+
4
(T o ta lAm m o n ai )
O
H CO
2
N it ro s om o n a s s p .
3
CO
N itr if ci a toi n
NO 2
N
( it r ite )
O
H CO
3
2
2
N it ro b a c te r s p .
CO
2
NO
3
N
( it ra te )
Bulk Water
Boundary Layer
Heterotrophs
Nitrifier rich
Inert Materials
Material Surface
Biofiltration
Bulk Water
Boundary Layer
Heterotrophs
Nitrifier rich
Inert Materials
Material Surface
0.45 kg/m3
TAN Conversion (gms/m3-day)
USDA - SBIR/AST, 97
500
400
300
200
100
0
Beads
Modified Beads
Tubes
Production Units
Propellor-washed Floating Bead Filters
F i ltra t oi n
B a c kw a s h ni g
Broodstock
Return
Bypass
Anti-siphon
valve
Sludge View Port
Pressure Gauge
Sludge
Intake
ADM Tilapia System
Gas Exchange
Feeding
Circulation
Biofiltration
Fish Tank
Solids Capture
Aeration
Degasification
Gas Exchange
Different Behavior
• Oxygen
– 21% of air
– Saturation 10 mg/l
– Poorly soluble
– Transfer H20 limited
• Carbon Dioxide
– 0.035% of air
– Saturation 0.5
mg/l
– Highly soluble
• 50 mg/l +
– Transfer gas
limited
Oxygen goes in easier than CO2 comes out
Gas Exchange
No CO2
Removal
Enrichment Devices
•Commonly used for large
scale applications
•Self-generates pressure
(150-200 psi)
•1 m3 liquid860 m3 gas
•Dependent on local source
of liquid oxygen
•Not impacted by power
failure
•15-35cents/kg typical
Liquid Oxygen
Timmons and Lorsordo (1994) pg. 188
Gas Exchange
•
•
•
•
•
Air stones
Paddle wheels
Surface Agitators
Spray nozzles
Packed columns
Ambient Air –Oxygen Addition and
Carbon Dioxide removal are balanced
Gas Exchange
Ambient Air Options
Circulation
Feeding
Circulation
Biofiltration
Fish Tank
Aeration
Solids Capture
Degasification
Circulation
Circulation Options
Air
Airlift
Pump
Air
Airlifts Perform Several Functions
Air
Air
–
–
–
–
Circulation
Aeration
C02 stripping
Foam control
Filter Mode
Drop Filters : Low Water Loss
Floating Bead Bioclarifiers
(2 )
W a te r F low
A
B
(1 )
(7 )
(5 )
W a te r F low
(6 )
C
E
(4 )
A ir F low
A ir
W a te r
Settled Backwash
Waters returned to
system
D
Air Bleed
Builds Charge
W a te r
S lu d g e
P a ten t # 5 ,7 7 0 ,0 8 0
(3 )
Backwash
mode
(2 )
Drop Filters : Low Water Loss
Floating Bead Bioclarifiers
Released Air Washes Beads
(1 )
W a te r F low
(7 )
(5 )
(6 )
C
E
(4 )
A ir F low
A ir
W a te r
Internal Sludge Capture
P a ten t # 5 ,7 7 0 ,0 8 0
(3 )
FAS 1012C: Recirculation Aquaculture Quiz
Name:_________________
List the five major treatment objectives and explain what they do.
Feeding
Fish Tank