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Hatchery Design and Construction, Part 2: 

Hatchery Design and Construction, Part 2

SEAWATER TREATMENTWATER QUALITY IS EVERYTHING!: 

SEAWATER TREATMENT WATER QUALITY IS EVERYTHING! PRE-FILTRATION VIA WELL SCREEN EXTERNAL RESERVOIR FOR STORAGE/SALINITY CONTROL PRESSURIZED SAND FILTRATION (20-50 MICRON) CARTRIDGE FILTRATION (5 + 1-0.5 MICRON) OZONE CONTACT DISINFECTION/DEGASSING IN-LINE UV STERILIZATION IF OZONE DE-GASSED IN-LINE HEATING ON FLOW-THROUGH TANKS

Seawater Pumps: 

Seawater Pumps Two types: Intake pumps (large, used to fill reservoir) Distribution pumps (for pressurization through treatment process and subsequent distribution) Intake pumps can generate flow up to 2,000 gpm (most hatcheries have flow rates around 500 gpm or less) Pumps are housed in protected, well-ventilated area, w/easy access Must be self-priming unless filled by positive head from intake Must also have water-lubricated mechanical seals Pumps are typically cast iron or fiberglass with hydraulic flow meter on discharge side (used to monitor flow)

Hatchery Pumps: 

Hatchery Pumps

Storage Reservoir: 

Storage Reservoir

Storage Reservoir: 

Storage Reservoir Inside view From outside

Seawater Filtration: 

Seawater Filtration Water in reservoir is often chlorinated/dechlorinated and then passed by distribution pumps through filtration process Mechanical filtration is a process of gradual reduction in size of particle filters: 20µM  5 µM  0.5-1.0 µM Reduction of particles to less than 20 µM is accomplished by rapid sand filtration (also referred to as pressurized sand filtration) Sand filtration typically uses swimming pool type filters rated to about 40 psi, 100 gpm flow and installed in parallel Most have multiple use valves (recirc, filter, backwash, etc.) and are filled with various grades of sand (usually 0.95-1.50mm silica sand)

Seawater Filtration: pressurized sand filters: 

Seawater Filtration: pressurized sand filters

Sand Filters: 

Sand Filters Usually more than one filter is required Sometimes various grades of sand are used in serial arrangements of filters Capacity: typically 40-140 gpm Can use diatomaceous earth filters (better filtration capacity, but more maintenance)

Seawater Filtration: 

Seawater Filtration Water from sand filters is then passed through a battery of cartridge filters Several cartridges are typically housed within one common cannister Cartridges are supposedly reusable (but cleaning’s tough!) Cannisters or housings should have shut-off valves and pressure guages As mentioned, cartridges are both 5 µM and 0.5-1.0 µM; flow rate capacities depend upon number/size of cartridges/housing Number of sand filters and various cartridges depends on level of filtration desired, quality of incoming water and overall flow rate demand

Subsequent Seawater Treatment: 

Subsequent Seawater Treatment The next step is to take this filtered water and elevate it to a gravity head reservoir Typically about 20 MT and used only for gravity flow Some treatment of seawater takes place here in the form of either ozonation or chlorination Most hatcheries have “double” reservoirs for treatment/storage (alternating days) Ozonation typically accomplished via venturi injection or micropore diffusors (diffusors must be ozone-resistant) Ozonation criteria: depends on dosage (mg/L) and contact time (longer contact time = lower dosage); usually 0.1 mg/L for 1 hr. If working flow rate is 200 gpm, storage must be 6,000 gallons.

Elevated Reservoir: 

Elevated Reservoir

Reservoir/Seawater Filtration: 

Reservoir/Seawater Filtration

Subsequent Seawater Treatment: 

Subsequent Seawater Treatment After ozonation, water is typically “stripped” of ozone via an aerated column Some hatcheries prefer to entrain a small amount of ozone in the line to keep water distribution lines clean Some hatcheries will then use UV disinfection to strip ozone from water UV disinfection is recommended in order to

Slide16: 

OCEAN 1mm WELL SCREEN OVERFLOW EFFLUENT TREATMENT MAIN SW PUMPS (2) SEAWATER TREATMENT SCHEMATIC PRESSURIZED SAND FILTERS (PSF) OVERFLOW TO RESERVOIR OVERFLOW TO RESERVOIR LARVAL MODULE CULTURE TANKS MATURATION MODULE CULTURE TANKS HEAT EXCH. HEAT EXCH. UV UV MAIN DRAINLINE DE-GAS STORAGE RESERVOIR PUMPS PSF 5 MICRON FILTERS 1 MICRON FILTERS OZONE CONTACT COLUMNS COMPRESSOR COMPRESSOR OZONE UNIT OZONE UNIT BLOWER BLOWER MATURATION MODULE RESERVOIRS LARVAL MODULE RESERVOIRS FRESHWATER BRINE TANKS

SEAWATER DISTRIBUTION SYSTEM: 

SEAWATER DISTRIBUTION SYSTEM SEAWATER USUALLY DISTRIBUTED FROM GRAVITY HEADER TANK INDIVIDUAL 4" PVC LINES FOR EACH PRODUCTION AREA SUPPORTED BY WALL BRACING, ROOF FRAME W/ DOWNLINES TO TANKS CONTROL OF FLOW BY VALVES, FLOWMETERS SMALL TANKS CAN BE FILLED VIA COMMON DOWNLINE LINES OUTFITTED WITH CLEAN-OUT SWEEPS, TEES

AERATION DISTRIBUTION SYSTEM: 

AERATION DISTRIBUTION SYSTEM Aeration typically provided via large impeller-type blowers Blowers located distant from hatchery due to noise/vibration Distribution system relatively similar to that of seawater system, but has to deal with condensation Incoming air is filtered to 1 µM via intake filters (prior to blower) Air from blower is often hot due to back pressure (cooled via immersion into water)

AERATION DISTRIBUTION SYSTEM: 

AERATION DISTRIBUTION SYSTEM Pipe extending from blowers is often constructed of metal due to high heat Ozone can be injected into pneumatic flow for disinfection of distribution lines or for in-tank treatment Aeration diffusion is typically via airstones or microbubble diffusors (e.g., plastipore tubing, Schramm Bioweave) Very little hatchery aeration is via compressor due to large volume required

Calculating Aeration Required: 

Calculating Aeration Required Most hatcheries operate with shallow-depth tanks Pressure requirement is small, but volume requirement is large Pressure typically recorded in psi (lbs. per square inch) and volume in cubic ft (cf) Flow rate is measured in cfs for most blower installations

Which Delivery System is Best?: 

Which Delivery System is Best? Difference between delivery systems is primarily a function of pressure Step 1: identify pressure required Depends on water pressure at depth of diffusor, piping/tubing friction loss and diffusor resistance to air flow For example: if most tanks in your hatchery are 36” deep (36 x .04 = 1.44 psi), your distribution pipes are low-restriction (total 0.15 psi) and your air diffusors are low-resistance (0.25 psi), total pressure needed is less than 2 psi. Note: most blowers operate efficiently up to 4 psi (this is the system you need!)

Aeration Criteria for Hatcheries: 

Aeration Criteria for Hatcheries Step 2: what is the total air flow you need? Most hatcheries use airstones as diffusors Most diffusors require about 0.5 cfm flow rate at most hatchery water depths (cfm increases with decreased pore size) With 500 airstones (possible) in a hatchery, you could need 500 cfm at 2 psi This equates to two 10 hp blower running simultaneously!

Air blowers: 

Air blowers

Aeration Distribution: 

Aeration Distribution

TANK CONSTRUCTION GUIDELINES: 

TANK CONSTRUCTION GUIDELINES Large, round tanks take up space, but are required for maturation Tanks constructed of cinderblock, poured concrete, fiberglass, or even liners Quality of fiberglass in developing nations is questionable (just weigh the tanks!) Fiberglass is expensive, so only use if you can lift the tank (i.e., use for algae production or spawning/hatching)

TANK CONSTRUCTION GUIDELINES: 

TANK CONSTRUCTION GUIDELINES Reduce large curves, need for hand-finishing of concrete Share tank walls to reduce cost Regardless of material type, all hatchery tanks should have a slick, glazed finish Tanks must be easily cleaned Tanks are usually constructed after the roof and walls are up

Ferrocement Construction: 

Ferrocement Construction

Maturation Tank: 

Maturation Tank 125 cm 4.00 m 65-75 cm 2% slope 1-10 gpm flowmeter w/valve unidirectional discharge Internal overflow standpipe

Spawning Tanks: 

Spawning Tanks

Slide30: 

TYPICAL LARVAL REARING TANK AERATION LINE SEAWATER LINE HARVEST PIPE (2"PVC) U-SHAPED BOTTOM CENTER SCREEN

Larval Rearing Tank: 

Larval Rearing Tank Many designs, everyone worried about sediment build-up Is “U”-bottomed design cost-effective? Main issue: water quality

Larval Rearing Tank: 

Larval Rearing Tank

Postlarvae Rearing Tanks/Areas: 

Postlarvae Rearing Tanks/Areas TAES/Flour Bluff Pulau Seribu, Indonesia Jepara, Indonesia UT/FAML, Port Aransas

ELECTRICAL SUPPLY AND DISTRIBUTIONDON'T TRY IT YOURSELF!: 

ELECTRICAL SUPPLY AND DISTRIBUTION DON'T TRY IT YOURSELF! Review requirements with a reputable electrical contractor or engineer Evaluate the local grid supply/quality (rem: some places plan power outtages!) If local quality is good, it’s still prudent to have an emergency back-up (make list of priority items, which are turned on first) Generators should be located distant from the hatchery (especially wrt maturation)

ELECTRICAL SUPPLY AND DISTRIBUTION: 

ELECTRICAL SUPPLY AND DISTRIBUTION Largest consumers are algae lighting, seawater pumps and aeration blowers Guard against moisture/contact Overall hatchery demand varies between 100 and 300 kVA If generator power is used, you must have two!

Electrical Consumption (medium-sized hatchery): 

Electrical Consumption (medium-sized hatchery)

Diesel Generators: 

Diesel Generators

LIGHTING/ILLUMINATION: 

LIGHTING/ILLUMINATION As mentioned, largely used for algae culture Extent of algae lighting determined by production schedule All algal species have specific growth criteria (wavelength/intensity) Maturation lighting has specific lighting requirement (rheostatically controlled) Normal indoor lighting should be via building codes

Algal Culture: 

Algal Culture Indoor algae culture requires roughly 50 KVA in illumination

HARVESTING OF TANKS(LARVAL/POSTLARVAL REARING): 

HARVESTING OF TANKS (LARVAL/POSTLARVAL REARING) Usually via common recessed trenches with floor drains Harvest trench is situation above drainage trench to avoid contamination Some facilities have “external” harvest areas/basins located adjacent to pack-out Floor drains should easily clear water from harvest floors; slope to outside of facility should be exaggerated to avoid air traps

Harvesting of PL’s: 

Harvesting of PL’s Trench should be wide enough to accommodate harvest vessels Trench should bisect rows of LRT’s or PLRT’s Allow at least 50 cm drop from LRT to harvest trench floor

HATCHERY DRAINAGE: 

HATCHERY DRAINAGE

EFFLUENT TREATMENT SYSTEM: 

EFFLUENT TREATMENT SYSTEM Used to protect environment from hatchery-sourced contamination: chemicals and biological threats Biological threat reduced via particle filtration and chlorine Chlorine volatilized via aeration Required in the U.S., but should be incorporated into all hatchery designs

Effluent Treatment: 

Effluent Treatment

DISEASE PREVENTION VIA DESIGNAN OUNCE OF PREVENTION...: 

DISEASE PREVENTION VIA DESIGN AN OUNCE OF PREVENTION... Reduce general access All workers shold pass through changing room (clean vs. dirty areas) Hatchery protected from intrusion via perimeter and security fences Hand and foot baths in critical areas Cafeteria /storeroom/repair shop located in clean area Separate maturation areas from larval and postlarval rearing areas