RecircFlowThruSystems March2011

8/7/2019 RecircFlowThruSystems March2011

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Dual-drain Tankuse in-tank settling ( swirl separation )intact fecal matter settles more easily

Cornell System

low solids effluent

high solids effluent

Central Double Drain for Tanks

Solidsco l l ec t i onbow l

Main f low s t ream

Center pipe

Se t t l eab l es t r eam

A

B

B

A

Se t t l eds t r eamou t f low

Raceway Dimensions Length:Width Ratio

of ~10:1

Depth 0.75-1.25 m aids in water flow easier management

(simplifies crowding,harvesting, grading,keeping separategroups)

water qualitygradient along lengthmay be observed

For Example: 40 m x 4 m x 1 m

40 m

4 m

1 m

Intensive trout production using largequantities of water in western NorthCarolina, USA.

Water and wasteflushedfrom the tanks

Carryingcapacity dependson available flow

Grading of trout.

FLOW-THROUGH SYSTEMS/PARALLEL-SERIAL RACEWAY SYSTEM

Aeration/Oxygen

Serial System

Raceway 1Raceway 2

Raceway 3

FLOW-THROUGH SYSTEMS

InfluentEffluent

Serial racewaysmaximize water useincrease water velocity for flushing wastes

FLOW-THROUGH SYSTEMS/SERIAL EARTHEN RACEWAY SYSTEM


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FLOW-THROUGH/RACEWAY SYSTEMS

Parallel System

Raceway 1

Raceway 2

Raceway 3

Effluent

Influent

Parallel raceways/tanks built side by sidemay share common wallsreduce floor spacereduce construction cost Combination Series and Parallel System

Effluent

Influent

Raceway

RacewayRaceway

Raceway Raceway

Raceway

FLOW-THROUGH/RACEWAY SYSTEMS

FLOW-THROUGH SYSTEMS/PARALLEL-SERIAL RACEWAY SYSTEM FLOW-THROUGH SYSTEMS/PARALLEL-SERIAL RACEWAY SYSTEM

FLOW-THROUGH SYSTEMS/PARALLEL-SERIAL RACEWAY SYSTEM FLOW-THROUGH SYSTEMS/SERIAL RACEWAY SYSTEM


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Impact of Fish

Per kg feed:30 g Total Ammonia Nitrogen (TAN)

[25-55 g]500 g Fecal Solids [250-500 g]250 g O 2 [up to 1000 g]350 g CO 2 [up to 1380 g]

8 g P [up to 15 g]

Physical and biological processes that impact water quality in serial raceway systems

Algae

FLOW-THROUGH SYSTEMS / RACEWAYS

Management Considerations

Low dissolved oxygen Buildup of nitrogenous wastes Accumulation of settleable solids

Discharge of effluents- treat all discharges in a settling pond

with 1-2 day retention- pass effluent through a microscreen- dual drainage system- provide settling area in raceway

Mass-balance Analysis

V dDO out /dt = Q inDO in - Q out DO out - K DO F

But Q in = Q out = Q

Q (DO in DO out ) = K DO F

Q DO = K DO FDO in DO out

0 (at steady state)

Q, DO in , TAN in Q, DO out , TAN out

F

K M

V


Q DO = K DO FDO in DO out

Flow Requirement

where:

Q DO = required flow based on DO, m 3/day

K DO = oxygen requirement, 250 g O 2/kg feed

F = feed ration, kg feed/day = feeding rate x fish mass (M)

DO in = dissolved oxygen in supply water, mg/L = g/m 3

DO out = minimum/effluent dissolved oxygen level, mg/L = g/m 3

Example:

M = 250 kg fishFeeding rate = 2% of mass/dayDO in = 6 mg/LDO out = 2 mg/L

F = 0.02 x 250 = 5 kg feed/dayQ DO = 250 (5)/(6-2)

= 312.5 m 3/day= 217 L/min or Lpm= 57 gpm

Loading (L) = M/Q= 250/217= 1.15 kg f ish/Lpm


Q TAN = K TAN FTAN out TAN in

where:

Q TAN = required flow based on TAN, m 3/day

K TAN = TAN excretion, 30 g TAN/kg feed

F = feed ration, kg feed/day = feeding rate x fish mass (M)

TAN in = TAN in supply water, mg/L = g/m 3

TAN out = maximum or effluent TAN, mg/L = g/m 3

Example:

F = 5 kg feed/dayTAN in = 0.0 mg/LTAN out = 1.0 mg/L

Q TAN = 30 (5)/(1-0)= 150 m 3/day

< Q DO = 312.5 m 3/day



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Tank Volume, Hydraulic Retention Time, WaterExchange, and Turnover Rate

Q Q

V = Water Volume

Hydraulic Retention Time (HRT) = V/Q

= average time water stays in tank= the time necessary to fill one tank volume with a given Q

Example: V = 5 m 3; Q = 1 m 3 /hr; HRT = 5 hrs

CORRECT: The amount of water flowing into the tank equaledits volume in 5 hours (sometimes Turnover Rate).

WRONG: Complete water exchange is achieved in 5 hours!


In reality, flow-through water continuously dilutesthe tank water, and the time (t) needed to replace old waterwith any fraction (f) of new water (true water exchange)is computed using:

t = -ln (1-f) HRT = -ln(1-f) V/Q

Same Example : V = 5 m 3; Q = 1 m 3 /hr; HRT = 5 hrs

The time required to replace 50% (f=0.5) of old water

= -ln(1-0.5) 5 = 3.5 hrs

60%: t = 4.6 hrs 99%: t = 23.0 hrs90%: t = 11.5 hrs 99.99%: t = 46.0 hrs


The water exchange rate can also be expressed as follows:

f = (1 e -t/HRT )

Same Example : V = 5 m 3; Q = 1 m 3 /hr; HRT = 5 hrs


t (hr) f (%)

1 18.13 45.15 63.2

23 99.0

Prove!Q (m 3 /hr) 1 2HRT (hr) 5 2.5

t (hr) f (%) f (%)

1 18.1 33.03 45.1 70.05 63.2 86.5

12 90.9 99.2

V = 5 m 3f = (1 e -t/HRT )


Cross-Flow Raceways



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A floating pre-filterfor water supply.

A baffled sedimentation tankfor flow-through water treatment.

Natural systems characterized by highlyvaried physical and chemical characteristics

Recirculating systems designed to approximatemost fundamental aspects of natural systems,while allowing for overall control

Goal is to design reliable and cost-effectiverecirculating systems

Recirculating Systems: Brief Background Water is reconditioned and recirculated/reused/recycled

Elimination of significant water resource,energy, and space requirements[up to 120 kg/m 3 (1 lb/gallon) in tanks ]

Flexibility in location

Environmental control~ adaptability in what may be cultured~ waste mitigation~ managed production

Product quality control

ImportanceRECIRCULATING SYSTEMS

Recirculating Techniques

Culture Unit

Treatment

Culture Unit

Treatment

Continuousflow-through

Recirculating

Recirculating

Intermittentreplacement

Waste

PARTIAL

CLOSED

Waste

RECIRCULATING SYSTEMS


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Recirculating System Design

Rearing Unit

WaterTreatment

Solids removal Biofiltration Support processes

pH and Alkalinity control Foam fractionationUV and Ozone

Turbidity/Color removal Disinfection

Pump Airlift

Defining Recirculating Systems

An Aquaculture Production System that

Recycles and Renovates Water for the Culture of an Aquatic Organism.

Recirculating Systems Operation Defined by Daily Volumetric Exchange Rates. 0 - 20% Volumetric Exchange per day 7 10% will be wasted by a typical drum screen filter

typical of systems being used nowadays

Why Recirculating SystemsPROS Reduced Water Requirements Reduce Area Requirements (intensification) Control of Temperature (economics?) Potential for Water Quality Control (or not)

Potential for Waste Capture (a point source) Potential for Better Feed Conversion (tanks) Isolation of Product (from disease & pollution)

Better Inventory Control (can see & collectmortalities or morts)

High density even greater than 120 kg/m 3(1 lb/gallon) in tanks have been attained.

Why Recirculating SystemsCONS High Initial Investment

compared to other production technology

A Lot of People Profess to be Experts (but arenot)

Very Short Response Time (1/2 - 3/4 hr) Very Poor "Track Record"

failures have been common (some very large)hard to finance (because of these failures)economy of scale (cannot be ignored)

Uses For Recirculating Systems

HatcheryNurseryQuarantineAdvanced Fingerling ProductionPurging Market Sized ProductGrow-OutHolding System


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Pumps and Control Systems

Gravity Aerators,Agitators and Blowers

Aerates/oxygenates Degasses

(groundwater containsCO 2, CH 4, H 2, H 2S)

Settles Fe 2+ andMn 2+

Venturi tubes

Surface Agitator

Regenerative/Centrifugal Blower

Aeration & Degassing

Surface Aerators Regenerative/Centrifugal Blower (Low-pressure)

Centralized centrifugal blowers (15 kW@) Linear Air Pumps


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Roots/Rotary Lobe Blowers Rotary Vane Compressors

Piston Compressors

Diaphragm Compressors

Quick Selection Guide

Sample Air Blower Performance Curves

1 ft 3 = 7.48 gal1 gal = 3.785 L


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Example: 4 cfm need to be delivered adistance of 200 feet from a rotary lobeblower. The average line pressure is 3psi. There are no odd twists or elbowsthat need to be considered.

Recommend the pipe size.The minimum diameter of plastic pipewill be 3/4", causing approximately 7"H 2O resistance or pressure loss.The smaller 1/2" pipe would causeabout 25" of loss, which wouldprobably be unacceptable.A 1" pipe, costing little more than the3/4", might be an even better choice if there is the possibility of using more airin the future.

Air Diffusers

Air Diffusers

Sample Air Diffusers Specifications Oxygenation Non-pressurized

Downflow bubble contactor (DBC; Speece Cone) Countercurrent diffusion

column

U-tube diffusers

U-tubeDBC


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Packed Column Aerator(also Trickling Filter)

Trickling Filter Construction

Biof i l t e r med ia

Lo wpres su reai r inf low

Water d i s t r i bu t ionar m

Water inf low

Water Outf lowtank

Feeds and Feeding

Directional Broadcast feeder

Vibratoryfeeder

Feeds and Feeding

Demand feeder

Beltfeeder

Feeds and Feeding

Screw / Auger

feeder

Solids Removal


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Broad size spectrumHigh organic contentLow density (1.19 times that of fresh water)

FractionsDissolvedSuspended (settleable and non-settleable)

Solids Characteristics


Gravity separation (sedimentation) Filtration (screen, granular media,

porous media)

Flotation (foam fractionation)

Solids Removal Mechanism

Solid-liquid separation


Solids Removal Processes

Foam Fractionation

Granular Filter

Microscreen

Tube Settler/Submerged Filter

Cartridge Filter

CoarseScreens

PlainSedimentation

100 75 30 10Particle Size, microns


Typical Tank Water Input

A Much Better Water Inlet:Vertical Manifold

50 mmelbow

50 mmelbow

50 mmballvalve

50 mmelbow

50 mmx 100 mmreducerbushing(note: do not glue the 50 mmpipe into the 50 x 100 mmreducer bushing.)

100 mm x 100 mm x 25 mmreducer tee

25 mmelbow

25 mmclearPVC

100 mm cap

10 mmholesspacedevery 5 cmoncenter

Details for Vertical Manifold

FishCultureTank

Vertical Manifolds & DoubleDrains

Settleable SolidsEffluent

SuspendedSolids

Effluent


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Swirl Separator: Solids Settling

Settleable SolidsEffluent

ClarifiedEffluent for

furthertreatment

Swirl Separator

Sludge to Waste

80 90% of flow

10 20 % of flow

Outf low

Wasted i scha rge

Inf low

Swirl Separator

Outf low

Inflow

Settleable Solids (Gravity Removal) Settling tank Sediment trap Inclined tubes Hydrocyclone

(swirl separator)

Gravity Sump/Submerged Filter

INFLOW OUTFLOW

SludgeRemoval

Filter Media

Schematic of a Tube Settler/Submerged Filter


Submerged filters Simple Inefficient

Trickling filters Simple Aerates Submerged filter

Suspended Solids (non-gravity) Screen filtration

Expandable granular media Downflow (fine sand) Upflow (bead filter,

course sand)

Drum / Microscreen filters

Screen

Suction


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Drum / Microscreen Filtersin Tandem for Higher Flow

Outf lowto t ank

Water f i l t e r edth roughsc reen

Wasted i scha rge

Inf lowf rom t ank

Pressureb a c k w a s h

Microscreen/Drum Screen Construction

Propeller-washedBead Filter

(upflow)

Pressurized downflowsand filter

Airlift-operated Upflow Sand Filter

Sand Filter Construction

Water inf low

Perforated pla te / tubesfo r wa te r d i s t r i bu t ion

Water ou t f l ow

Sand(o r o the r med ia )

Break-bar

Biofilters Come in All Shapes and SizesMoving Bed

Filters arelow energy

and compact

FluidizedSand Beds are

the mostcompactbiofilter

Bead Filterscombine

nitrificationwith solids

removal

TricklingFilters arethe work horse of

aquaculture

An RBCspecificallydesigned foraquaculture

(RBC)

LowPressureAirInflow

Water Inflowfrom CultureTank

WaterReturn toCultureTank

BiofilterMediaPlastic Blocksor Plastic Rings

Rotating WaterDistributionArm


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BIOLOGICAL FILTRATION / BIOFILTRATIONliving organisms to treat water

primarily Nitrification in recirculating systems

Nitrification: AMMONIA NITRITE NITRATE

TAN (Total Ammonia Nitrogen) composed of both NH 3 andNH 4+ in a pH-dependent, acid-base relationship:

NH 3 + H 20 NH 4+ + OH -


Percent of Total Ammoniain the Unionized Form at

Various Temperatures and pH

Temperature oC ( oF) 7.0 8.0 9.0

10 (50) 0.19 1.83 15.7

20 (68) 0.40 3.82 28.4

30 (86) 0.80 7.46 44.6

pH

NH 4+ + 1.5 O 2 2 H + + H 2O + NO 2- [Nitrosomonas spp .]

NO 2- + 0.5 O 2 NO 3- [Nitrobacter spp .]

Nitrification


Overall with cell synthesis:

NH 4+ + 1.83 O 2 + 1.98 HCO 3- 0.021 C 5H 7O 2N +

0.98 NO 3- + 1.041 H 2O + 1.88 H 2CO 3

Requirements:4.57 g O 2 per g TAN7.14 g alkalinity as CaCO 3 per g TAN

optimum pH 7.5-8.0optimum temperature 25 oC

Nitrification


Carbonate-Bicarbonate System as Affected by pH

4.3 8.3 12.3PHENOLPHTHALEIN (P)

END POINTTOTAL ALKALINITY (T)

END POINT(Methyl Orange end point)

The Nitrogen Cycle in Aquaculture

Water plants Food

Excessfood

Fishes

PeptidesAmino acids

Urine

Urea

Ammonia(NH )

Algae

Nitrate (NO )

Nitrite (NO )

Feces

2

3

3

N2 Gas


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16

12

8

4

02 8 14 20 26 32

Nitrogen (mg/L)

TANNO2-N

NO 3-N

Time (days)

Biofilter Acclimation

Rotating biological

contactor External Internal

RBCmotor driven

In-tank RBCairlift driven

Air channel

RECIRCULATING SYSTEMS/ROTATING BIOLOGICAL CONTACTOR (RBC)

RBCmotor driven

Propeller-washed Bead Filters Propeller-washed Bead Filters

Polygeyser Bead Filter(Pneumatic drop filter)

Bubble-washedBead Filter

Propeller-washed Bead Filter Operation

Figure 1.


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Figure 2.


Figure 3.


Figure 4.

Bubble-washed Bead Filter

PolygeyserBead Filter



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Moving-bed Biofilters

Biofilter Media

Kaldnes Media

Modified Beads(EN enhanced nitrification)

Foam Fractionators

Schematic of Foam Fractionators[fine particles (organics, surfactants) attach to rising bubbles]

(a) Cocurrent

Foamout

Air in

Waterout

Waterin

(b) Countercurrent

Waterout

Foamout

Air in

Waterin

AirliftPump


Other Components Lighting

low light levels reducestress to fish

Heaters/chillers depending on species

Chillers

Heater


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System Configurations

TANK PUMPSOLIDSFILTER

BIOFILTERAeration &Degasification

Screens Settlers

RECIRCULATING SYSTEMS RECIRCULATING SYSTEMS

RBC

TubeSettler

FishTank

TANK PUMP

SOLIDS & BIO-FILTERAeration &Degasification

Granular filters



TANK SOLIDS & BIO-FILTER

Aeration &Degasification AIRLIFT/PUMP

Granular filters Other combinations



EXAMPLES

Recirculating Milkfish Broodstock System

Natural spawning of milkfish ( Chanos chanosForsskal) has long been demonstrated by AQD inflow-through and partial recirculating systems.

Study conducted to evaluate recirculatingbroodstock system and fish reproductiveperformance.


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Combination Upflow and Fluidized Sand Filter

RecirculatingMilkfish Broodstock

SystemInletPipeManifold

FluidizedSand Filter

(0.3-0.4 mm sand)

UpflowSand Filter

(0.5-1.0 mm sand)

Backwash

To Tank

Sluice gate A

Gate B Gate C

Gate D

Sand

Pebbles

Gravel

Combination Upflow and Fluidized Sand Filter


Pumps

To backwash

Combination Filter

GravityAeration

200 m 3 Tank Schematic of Recirculating

Milkfish BroodstockSystem

Drain

Schematic diagram of the Quarantine System of the Tabuk Fisheries Company (TFC)

T o t r eat ment pond

Sand Filters

Ultraviolet

Filters

Sump

20 m 3Tank

Biofilters

Pumps

Legend:

Recirculation

Discharge

Bypass Bypass

Components: Six 20-m 3 fish tanks (5 fingerlings/L) and a 20-m 3 sump Three 6-kW recirculation pumps, each estimated to

pump a maximum of 100 m 3/hour Three sand filters (Astral Pool Model 00714) with 1.54-

m 2 cross sectional area, each rated at 46 m 3/hour (allhoused in an air-conditioned container room with theUV and electrical control panels)

Two 480-watt ultraviolet (UV) sterilizers Two 2-m 3 moving-bed biofilters for each fish tank (total

of 12 biofilters), each containing 1-m 3 of media forbiological filtration

An earthen, 4 4 0.5 m backwash water treatment

pond

Moving-Bed Biofilters

Sump TankPumps

20-m 3 Tank

A view of the TFC quarantine system showing the pumps, some20-m 3 tanks, the sump tank and six of the moving-bed biofilters.


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Container Room

Pipes leading to Sand Filters

Backwash Pipe

Pipe connections to and backwash pipe from the sandfilters that are inside the container room.

One of the three Astral Pool Model 00714 Sand Filter installedin the TFC quarantine system.

The UV Sterilizers and electrical control panels in thecontainer room. The sand filters are seen at the back.

Moving-Bed Biofilters

Water in

Sludge out

Biofilter Media

The moving-bed biofilters and pipe connections. Inset is the typeof biofilter media (10-mm diameter) used.

Earthen Treatment Pond

Quarantine System

Overall view of the TFC facility from the earthen treatment

pond in the foreground and the quarantine system in thebackground.


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Integrated Recirculating Tank Culture of Grouper and Seaweed

Integrated culture enhances productivity and

utilization of resources and inputs, while providingfor water quality control and waste mitigation.

Seaweeds known and reported to uptake ammonia a main fish metabolite.

Study conducted to evaluate:- Efficiency of Gracilariopsis bailinae as biofilter- Growth and amenability of Ephinephelus coioides

(grouper) to intensive tank culture- Dynamics of integrated tank culture system

Bypass

SeaweedUpflowSandFilter

Grouper

Grouper

Seaweed

Pump

WaterreplacementBackwash

Schematic of Integrated RecirculatingGrouper and Gracilaria System

9-m 3 Tank(BT-1)

Sand Filters

Backwash

Bypass

Pump intake at~mid-tank depth

CentralDrain

Drain

Pump

Gracilaria in trays in-tank; doubly serves asgrouper shelter

Schematic of Grouper and Gracilaria System

Highlights:

Together with the nitrification attained in upflowsand filters, about 3 kg Gracilariopsis bailinaeprovided sufficient uptake of ammonia nitrogenfrom 1.5 - 2 kg 43% protein grouper growout diet(i.e., minimum 2 kg gracilaria/kg feed)

The grouper Ephinephelus coioides can thrive inproperly designed and operated recirculating tanksystems at high stocking densities of up to about 70kg m -3; 180 fish m -3 for 330 g fish FluidArt

OR TANK

OR TANK


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Integrated Biofiltration and Gas Exchange

EffluentTrough

Continuous-Cleaning Multifunctional Biofilter


Integrated Recirculating Pond Culture

Pump Gracilaria

IntensiveShrimp

Fish &Mollusks

Settling

(Plankton throughout)Perforated Pipe

IntensiveShrimp

RELATED RESEARCH

IntegratedRecirculatingPond Systems

Effluent Treatment

Coddington et al. (1999) Aquacultural Engineering 19:147-161

Treatment of effluent from intensive (45/m 2)shrimp ponds can be effected by shuntingthe last 10-20% of discharge volume(final 20 cm of pond depth)through a settling pond with 6 hr residence.

Settling of Aquaculture Discharge

Mangroves to Process Shrimp Farm Effluents

P

Shrimp Pond(880 m 2)Reservoir

(888 m 2 net)

Impounded Mangrove Wetland (IMW)(320 m 2)

Airlifts


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Creek

IMW

6-24 h

Reservoir>12 h

Shrimp Pond1-5 d

(bacteria advisory)

WATER MANAGEMENT IN IMW STUDY

Highlights :

Ammonia reduction of 8-41% in IMW after 12-17 hrsholding; TSS reduction of 24-72%; variable resultswith nitrate and phosphorous.

Positive effect of conditioning the water in thereservoir before pumping into shrimp pond;

reduction in luminous bacteria in reservoir/shrimppond/IMW compared to creek; consistently


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Aquaponics integrated aquacultureand hydroponics

Aquaponics integrated aquaculture and hydroponics

Aquaponics integrated aquaculture and hydroponics Aquaponics integrated aquaculture and hydroponics

Grading Seabass Fry

Fish Transport

THE BOTTOM LINE ?!

Documents

RecircFlowThruSystems March2011