Zero water cultu. sys.(ras) me

Zero water exchange culture system
(Close Aquaculture System)
jitenderanduat@gmail.com

Closed Aquaculture Systems
 Closed system aquaculture refers to the
of aquatic species in raceways, tanks and ponds.
 Recirculation technology is implemented which cycles water
through filtration processes and returns it back into the
aquaculture system.
 This process aids in maintaining water quality whilst ensuring
minimal exchange with natural waterways.jitenderanduat@gmail.com

Types of Culture
 Extensive (few organisms per aquatic space).
 Semi-Intensive (more organisms per space).
 Intensive (many organisms per aquatic space).
 Super Intensive (too many organisms per
space).
Aquaculture Systems.

Tank Culture.
 Concrete, fiberglass?
 Indoor or outdoor?
 Static or water exchange?

Traditional extensive system
1) Where no exchange of water
2) Food is natural
3) Natural seed stocking in traditional system
4) Production - not fix
5) Operated in - pond

Zero water exchange
system
1) Seed stocking done from hatchery
2)Low seed stocking
3)Artificial feed will be provided
4) No water exchange/ just for maintaining water
5)Production- 500to 800 kg/ha
6)Followed for- shrimp, IMC, Seabass in some part of India
7) operated - only in pond

Modern Zero water
exchange System
 It is also known as re-circulating Aquaculture
Systems (RAS). Or indoor culture system.
 Recirculating aquaculture systems (RAS) are the
newest form of fish farming production system.
 RAS are typically an indoor system that allows for
farmers to control environmental conditions year
round.

RAS
 While the costs associated with constructing a RAS
are typically higher than either pond or cage culture.
 RAS are the most complex aquaculture systems.
 It is land based system.

Conducted in
 Circular cement tanks
 Reinforcement circular cement tank
 Reinforcements Rectangular tank
 Circular fiber tank
 Circular rectangular tanks.

Background
 The most intensive systems used for production of
aquatic organisms are re-circulating systems
 Total environment is controlled
 Key operating parameters: minimal energy input
and proper water quality management
 Water circulates through the entire system and only
a small portion of new water is added daily

Cont..
 Physio-chemical parameters must be
controlled: temperature, salinity, pH, alkalinity,
chemical composition, oxygen
 Solid wastes are filtered, water is re-
oxygenated and re-circulated water undergoes
nitrification
 Re-circulating aquaculture systems are more
capital-intensive than most other types of
traditional production systems
 Rely on economic productivity per unit volume of
rearing space for profitabilityjitenderanduat@gmail.com

Cont..
 Must have support facilities (e.g., backup
generators) whose cost is also part of overall
production costs for the farm
 Large production levels are achieve via
modulation of individual self-sustaining units
 Production units are also designed for species
flexibility – essential now-a-days!

THE RAS DESIGN
 (1) Growing tank,
 (2) Sump of particulate removal device,
 (3) Biofilter,
 (4) Oxygen injection with U-tube aeration and,
 (5) Water circulation pump.
Depending on the water temperature and fish
species selected. A water heating system may be
necessary.
o 6) Ozone and ultraviolet sterilization also may be
advantageous to reduce organic and bacteria loads.

Water supply
 Quality and Quantity water.
 Ground water obtained from deep wells.
 Springs is the best source of water
 Free of pollutants.
 Municipal water supplies also can be used
after chlorine, floride, and other chemicals
areremoved.

Bio-filtration
 The biological filter (biofilter) is the heart of the RAS.
 Two primary water pollutants that need to be removed
 (1) fish waste(toxic ammonia compounds) excreted into
the water.
 (2) uneaten fish feed particles
 The biofilter is the site where beneficial bacteria remove
(detoxify) fish excretory products, primarily ammonia.

Bio-filter
 (1) Submerged bed filters
 (2) Emerged bed filters.

Bio-filtration for NH3 removal

AQUAGRIS WORKSHOP (Bremen, GERMANY) - Saturday 9th February2008
NITRIFICATION /
DENITRIFICATION
NO3
- N2NO2
- NO N2O
NH3/NH4
+ NO3
-+ O2
NO2
-
 Nitrification:
 Denitrification (Anaerobic processes):
PerspectivesHerbivorySaprophagy
Introduction

Water requirements
Most RAS require less than 10% of the water and much less
land than ponds to grow the same amount of product
At the same time, produce continuous crops (i.e., no seasonal
impacts)
RAS offer a high degree of environmental control,
mitigating risks such as natural disaster, pollution and disease
Other at production systems with low environmental impact
Effect: production brought closer to the consumer

How Much Water is
Required?
For site selection of RAS, one must think in
terms of the initial facility and eventual modular
expansion
Source capacity:
fill all tanks within 24-48 h
provide for routine/emergency flushing of
tanks
filter backwashing
washdown and clean-up
domestic requirements
This is usually over 100,000 gpd with a process
flow rate of >70 gpm

Benefits to Recirc. Use of
Water
Decrease in water demand
Reduced overall discharge water
Reduction in water heating/cooling
Almost total control over water quality factors
Optimization of land use
Modulation potential = biosecurity
Reduction treatment costs of discharge streams

Types of RAS
Serial re-use, partial re-use, and fully re-
circulating systems
Serial: water from one system is enriched with
oxygen and goes to a subsequent one
Partial: additional treatment of a portion of the
system water volume, then re-used
Fully recirc: very high degree of re-use, more
treatment processes, systems separate

Major limiting factor
 oxygen (determines density), followed
by unionized ammonia and carbon
dioxide
(CO2 affects pH,
pH affects proportion of ammonia that is
unionized).

Stocking Rates of fish
L = 0.06(Dfish/R)
How many fish/shrimp can I put in the system?
“Loading” refers to the fish mass that can be
maintained per unit of flowing water: kg/l or lbs/g
Loading capacity depends upon water quality,
fish/shrimp size, species (mainly for fish)

SPECIES TO BE CULTURED
 RAS are currently being used to grow
 Catfish,
 Sea bass,
 Tilapia,
 Blue crabs,
 Oysters,
 Mussels
 Aquarium pets.

Recirculation Rates
 45 gallons per minute (63,360 gallons
per day)
Feeds and Feeding
 A complete feed, containing all the
essential minerals and vitamins.
 Feed of dry, floating pellets
 Are fed 3 to 5 percent of their body
weight
 Automatic feeders and demand feeders

Major problems in
aquaculture.
 Environment needs filtering.
 Oxygen needs to be replenished.
 Organisms cannot be seen.
 Diseases spread too fast.
 The inside of organisms is constantly in
contact with outside medium.

Therefore, the systems
should:
 Keep the medium acceptable for survival
and optimal growth.
 Replenish oxygen and remove carbon
dioxide.
 Make organisms accessible for inspection.
 Fight diseases.
 Just make it comfortable for the organisms.

Thank You

Zero water cultu. sys.(ras) me

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Zero water cultu. sys.(ras) me

Similar to Zero water cultu. sys.(ras) me (20)

More from College of Fisheries, KVAFSU, Mangalore, Karnataka

More from College of Fisheries, KVAFSU, Mangalore, Karnataka (20)

Recently uploaded

Recently uploaded (20)

Zero water cultu. sys.(ras) me

Editor's Notes