Durgeshwari
Department of Agronomy, IGKV, Raipur
Dr. Subuhi Nishad
Programme Officer (NSS Girls Unit), IGKV, Raipur


INTRODUCTION
Bio-Floc Technology (BFT) is considered as new “blue revolution” since nutrients can be continuously recycled and reused in the culture medium, benefited by the minimum or zero-water exchange. BFT is an environment friendly aquaculture technique based on in-situ microorganism production. Biofloc is the suspended growth in ponds/tanks which is the aggregates of living and dead particulate organic matter, phytoplankton, bacteria and grazers of the bacteria. It is the utilization of microbial processes within the pond/tank itself to provide food resources for cultured organism while at the same time acts as a water treatment remedy. Thus, this system is also called as active suspension ponds or heterotrophic ponds or even green soup ponds.

Semi- biofloc technology
Semi- biofloc fish production technology is collaboration between pond culture and biofloc technology as some fish species prefer mud to complete their life cycle entirely or any stage of life e.g.- Tilapia (Oreochromis niloticus).

Working principle of BFT
  • Biofloc system is a wastewater treatment which has gained vital importance as an approach in aquaculture.
  • The principle of the technique is to maintain the higher C-N ratio by adding carbohydrate source and the water quality is improved through the production of high quality single cell microbial protein.
  • In such condition, heterotrophic microbial growth occurs which assimilates the nitrogenous waste that can be exploited by the cultured species as a feed and also works as bioreactor controlling of water quality.
  • Immobilization of toxic nitrogen species occurs more rapidly in biofloc because of the growth rate and microbial production per unit substrate of heterotrophs are ten-times greater than that of the autotrophic nitrifying bacteria.
  • This technology is based on the principle of flocculation within the system.

Advantage of BFT
  • Eco-friendly culture system.
  • It reduces environmental impact.
  • Judicial use of land and water
  • Limited or zero water exchange system
  • Higher productivity (It enhances survival rate, growth performance, better feed conversion in the culture systems of fish).
  • Higher biosecurity.
  • Reduces water pollution and mitigate the risk of introduction and spread of pathogens
  • It reduces utilization of protein rich feed and cost of standard feed.
  • It reduces the pressure on capture fisheries i.e., use of cheaper food fish and trash fish for fish feed formulation.

Major cultivable fish species in BFT
A basic factor in designing a biofloc system is the species to be cultured. Biofloc system works best with species that are able to derive some nutritional benefits from the direct consumption of floc. Biofloc system is most suitable for species that can tolerate high solids concentration in water and are generally tolerant of poor water quality. Some of the species that are suitable for BFT are:
Species suitable for Biofloc culture
  • Air breathing fish like Singhi (Heteropneustes fossilis), Magur (Clarias batrachus), Pabda (Ompok pabda), Anabas/Koi (Anabas testudineus), Pangasius (Pangasianodan hypophthalmus)
  • Non air-breathing fishes like Common Carp (Cyprinus carpio), Rohu (Labeo rohita), Tilapia (Oreochromis niloticus), Milkfish (Chanos chanos) Shellfishes like Vannamei (Litopenaeus vannamei) and Tiger Shrimp (Penaeus monodon).

Fig.- Aerator installation & observation of water quality and floc volume



How to Prepare the Inoculum?

METHOD-I
For 15000 Litres of fresh water 150 Litres of inoculum is required for the floc development

Step 1
Take clean tub/can with 150 Litres of water and continue vigorous aeration

Step 2
Add 3 Kg of pond soil + 1.5 gm of Ammonium sulphate /Urea + 30 gm of carbon source (Jagerry /Wheat flour /Tapioca flour)

Step 3
Mix it well with water in tub and provide adequate aeration

Step 4
The inoculum will be ready after 24-48 hrs and it can be transferred to main tank
  • Daily addition of carbon source is required for the development of floc. For every 1 kg of feed given (with 25 % of crude protein), 600 gm of carbon source is to be added to the system to maintain C: N of 10:1.
  • Once the floc volume reaches 15-20ml further addition of carbon source is not required.

METHOD-II

Step 1
Take clean tub/can with 130 Litres of water and continue vigorous aeration

Step 2
Add 20 Litres of pond water/RAS water (before filtration) + 30 gm of carbon source (Jagerry /Wheat flour /Tapioca flour) + 10 gm of probiotic (with Bacilus Sp., Aspergilus Sp. etc with a total concentration of 10x109 CFU/gm)

Fig- Circulatory hatchery unit facilitate uniform egg hatching and fish harvesting in Semi Bio-Floc tank.



Follow the remaining steps as mentioned in method 1
  • NB: Well developed inoculum will be turbid with foam on the water surface (Ideal Volume of Floc in Imhoff cone for shrimp is 10-15 ml/L and for Fish 25-35 ml/L)

Quality parameters for Biofloc, Semi-biofloc fish production technology

S.N.

Particular

unit

1.

pH

7.5-8.5

2.

C:N

10-15:1

3.

Temperature

25-35⁰C

4.

DO

5-10mg/l

5.

Water colour

Clear green to brown

6.

Turbidity (Sechidisc transparency)

20-35cm

7.

Salinity A. Fresh water

0-0.5 ppt

 

B. Brackish water

0.6-35 ppt

 

C. Marine water

35.1-45 ppt

8.

TDS (Species Dependent)

 

 

a. Rohu, Catla, Mrigal, Carps and Tilapia

500-1000

 

b. Magur,  Singhi, Cat fish

1000-1500

10.

Stocking density (species, size dependent)

1m3 water/fish

11.

Fish classification based on size

 

 

i.            Spawn

6-8mm

 

ii.            fry

20-25 mm

 

iii.            fingerlings

30-40 mm(Early)

 

 

50-60 mm

 

 

≥ 100 mm (Advance)

 

Others

uses

 

KMnO4

for Sanitization

 

Molasses

a. Source of energy for bacteria,

b. balance Nitrogen

 

Medifish Unique @ 50ml/10,000 L water

Injury care

 

Vitagro Unique 1%

Vit.+ mineral mixture

 

Unique growth, Probocare

Growth promoter

 

Probiotic active  200 gm

Fermented carbon organic

Feeding Chart

S.N.

Avg. Body weight

Feed%

Feed Size

% Protein

Time

1.

‹ 1gm

200

Powder

› 45

4 times

2.

1gm

10

0.5mm

40

3 times

3.

10gm

5

2mm

30-32

2 times

4.

50 gm

3

3-4 mm

28-30

2 times

5.

› 100 gm

2

6 mm

24-28

2 times

Note: Crude Protein contents 16% nitrogen


Model Cost Break up for Construction of Biofloc ponds for Freshwater areas including inputs of Rs. 4 lakhs/0.1ha

Capital cost

S.No

                           Component

Total (Rs in lakhs)

1

Earth work excavation and construction of bund

0.50

2

Polyethylene lining

1.50

3

Inlet, outlet and central drainage system

0.50

4

PVC pipe fittings for air, water flow

0.50

5

Pump house-100sqf

1.00

6

Pumps-1 nos. 3 HP

0.30

7

Aerator-4 nos. @Rs.25,000

1.00

8

Air Blower

0.30

9

Aeration tubes

0.30

10

Generator set 10 KVA

2.00

11

Net, Imhoff cone, weighing balance, water testing kits and other

accessories

0.30

12

Bio security Measure-Bird net, crab net

0.20

13

Electrification L.S.

0.50

14

Watchman shed-10sqf

1.00

13

Miscellaneous

0.10

Total

10.00

 

Input cost

Sl. No

Component

Total Amount (In Lakhs)

1

Seed cost @ Rs.3/pc for 10500

0.30

2

Feed cost @ Rs.30/kg for 10MT

3.00

3

Electricity and fuel

0.70

 

Total

4.00

Source- National Fisheries Development Board, nfdb.gov.in

Grand total: Rs.14 Lakhs

CONCLUSION AND FUTURE PROSPECTS

1. Farmers near urban market can earn money from Biofloc, semi-biofloc fish production technology throughout the year once they establish production unit and acquire knowledge and skills.

2. There is increasing demand for fish at competitive rate both in domestic and export market as they are quality source of animal protein.

3. Fish farming has huge market of seed producers, suppliers, fish farmers, distributor and value added product makers, sellers, transporters etc. one biofloc, semi bio-floc fish farming unit can give employment to many people.

4. Bioflo, semi-biofloc fish farming units are less affected by external factors as all are under observation within the tanks, thus risk of failure due to external factors can be minimized or checked as there is poor soil quality for crop production at village level.

REFERENCE

Azim M, Little DC. The biofloc technology (BFT) in indoor tanks: water quality, biofloc composition, and growth and welfare of Nile tilapia (Oreochromis niloticus). Aquaculture, 2008; 283(1-4):29-35.

Chamberlain GW, Hopkins SJ. Reducing water use and feed cost in intensive ponds. World Aquaculture. 1994; 25:29-32.

De Schryver P, Crab R, Defoirdt T, Boon N, Verstraete W. The basics of bio-flocs technology: the added value for aquaculture. Aquaculture. 2008; 277(3, 4):125-137.

Hepher B. Aquaculture intensification under land and water limitations. Geo Journal. 1985; 10(3):253-259.

National Fisheries Development Board, nfdb.gov.in

Schneider O, Sereti V, Eding EH, Verreth JAJ. Analysis of nutrient flows in integrated intensive aquaculture systems. Aquaculture Engineering. 2005; 32(3, 4):379- 401.