Flocponics advantage over Aquaponics and RAS. Water quality improvement

1. FLOCPONICS AND ITS ADVANTAGE
OVER THE RAS AND AQUAPONICS
By:
B. Bhaskar

2. Introduction
• The world population already reached 8 billion in the year 2022 and the
global demand for safe & healthy food has increased significantly in the last
few years due to world population growth, projected to reach 9.7 billion
people in 2050.
• Providing them with healthy food is a major global challenge, especially in
the current scenario of natural resource scarcity, due to productive habitat
conversion for non productive purposes & destruction of wild diversity
reach areas, multi sources of pollution load, desertification, increased
frequency of natural and man made disasters, Climate change impacts on
Aquatic and land resources slowly increasing resulting in unpredictable
crop yields.
• Many countries still face problems with hunger while others are trying to
address their high rates of population obesity and malnutrition.
• Hence, investment and research into sustainable food production
technologies that produce nutritious food and consume fewer natural
resources are needed.
• FLOCponics is an alternative type of aquaponics that integrates biofloc
technology (BFT) with soilless plant production.
• FLOCponics is defined as the integration of biofloc-based aquaculture with
hydroponics. Thus, FLOCponics is an alternative type of aquaponics system
where RAS is replaced by a system based on BFT

3. • Biofloc Technology (BFT) was developed in the 1970s, by the French
Research Institute for Exploitation of the Sea (IFREMER).
• Their aim was to improve the productive performance of aquatic animals
and solve problems of disease outbreaks in marine shrimp farming.
• The promising results of BFT were disseminated and, due to its flexibility,
such technology is also currently applied in fish farms.
• Biofloc-based culture is characterized by the presence of specific microbial
communities, which enable the intensive and biosafe culture of aquatic
organisms.
• The growth of heterotrophic bacteria is stimulated by the manipulation of
the carbon:nitrogen (C:N) ratio, normally ranging from 10 to 20:1, with
constant water movement and aeration and minimal water exchanges.
• In addition to heterotrophic bacteria, chemoautotrophic bacteria and
planktonic organisms, mainly microalgae, copepods, cladocera, protozoa and
rotifers, are also frequently reported in biofloc cultures
• BFT trophic level, usually categorized as photoautotrophic (algae-based
system), chemoautotrophic (based on nitrifying bacteria), heterotrophic
(based on heterotrophic bacteria), or mixotrophic systems

4. • An aquaponics system basically consists of aquatic organism tanks and filters
(mechanical and biological), which make up the recirculating aquaculture system,
connected to hydroponic beds
• In aquaponics systems, aquaculture effluents are transformed by nitrifying bacteria
into bioavailable nutrients for plants, supporting almost full feed utilization and
plant growth.
• In aquaponics, nutrients are recycled and low volumes of water are used, which
reduces the negative environmental impacts usually associated with low efficiency
in the use of natural resources in conventional food production.
• Aquaponics and biofloc-based aquaculture are considered environment-friendly
approaches to food production. Both are intensive aquaculture systems with a
strong focus on nutrient recycling and water saving.
• The term ‘FLOCponics’ was proposed by Pinho et al. to identify and unify the
systems that have been called ‘BFT+hydroponics’, ‘BFT+aquaponics’ or ‘BFT+plant
production.
• The recommended range of solids concentration for the production of tilapia and
shrimp in biofloc-based systems are 5 to 50 and 5 to 15 ml L−1, respectively,
usually measured as volume of bioflocs in Imhoff cones.

5. •
With respect to the aquaculture
subsystem, tanks with different
volumes have been used, varying
from 125 to 1000 L to more than
100,000 L. The high volumes of fish
tanks (>100 m³) were reported by
Rahman, Blanchard et al., Pickens
et al. and Doncato and Costa. These
authors took the effluent from BFT
tanks daily or weekly, streaming the
water for plant production in
decoupled systems. In addition, a
remarkable feature was the use of
artificial substrates in the shrimp
tanks (by Silva, Neto,and Poli et
al,). These authors did not test the
effects of the substrates on
FLOCponics production, they were
used as a management usually
recommended for shrimp growth in
BFT

6. Studies on Decoupled FLOCponics systems as an alternative
approach to reduce the protein level of tilapia juveniles' diet in
integrated agri-aquaculture production, carried out by Sara M.Pinho
et al,(2021), their key findings reveled as
• Decoupled layouts allow reduction of critical issues
related to FLOCponics systems.
• Benefits of bioflocs for fish nutrition are also seen in
decoupled FLOCponics (DFP).
• DFP outperforms fish yield of decoupled aquaponics
(DAPS) by 24%.
• DFP leads to 8% reduction in the fish dietary crude
protein (CP) compared to DAPS.
• Lettuce grows similarlly regardless of the system
and the level of CP.

7. Economic comparison between conventional aquaponics and
FLOCponics systems
• The economic feasibility of FLOCponics and aquaponics production
in Brazil was compared.
• The investment to start a FLOCponics (FP) and conventional
aquaponics (AP) production is similar.
• Labor is the costliest operational item in both FP and AP systems.
• At least 68.7% of the plants grown should be visually marketable to
make FP profitable.
• Regardless of the scenario, it is economically feasible to produce
tilapia juveniles and lettuce in an AP system

8. Optimum range of water quality in Aquaculture
• Imp water quality parameters of the Aquaculture system; A) Physico-chemical
parameters”DO, BOD, COD, EC, TDS, TSS, PH.
• B) Heavy metals: NI, Cd, Cr, Zn, Fe, Hg, Ag, Au, Pb.
• C) biological contaminants; D): PAH’s, PCB’s, POP’s, PPCP’s, Petroleum hydrocarbons,
pesticides, dioxins, furans.
• The accepted range for Dissolved oxygen (DO) are values equal to or greater than 5 mg/L
(Abbassy, 2018).
• BOD is however the measurement of the total dissolved oxygen consumed by
microorganisms for the biodegradation of organic matter such as food particles or sewage etc.
(Bhatnagar and Devi,2013).
• Clearly, this would be indicative of both the total organic content of the water body and the
microbial load.
• According to regulatory bodies, BOD for inland aquaculture ecosystems is best kept in the
range of 2–4 mg/L (Chapman, 1996).
• COD on the other hand is a measure of the total oxygen equivalent of the organic matter in
the aquatic biota which is susceptible to oxidation by a strong chemical oxidant such as
dichromate (Chapman, 1996).
• As per the World Health Organization (WHO) recommendation for aquaculture, COD should
be kept within the range of 20–100 mg/L.
• The optimal range for the Electrical Conductivity (EC) of fish culture according to (Stone and
Thomforde, 2004) is 100–2000 μS/cm.

9. Con…
• EC is a measure of the conductivity of electricity by the biota
which depends greatly on its salt content.
• The TDS of a water body is the measurement of inorganic salts,
organic components and other dissolved constituents in water
(Weber‐Scannell and Duffy, 2007).
• Traditional means of water purification are most suited for
reducing TDS because they are easily removed by a filtration
mechanism.
• Saleh reported in a study on the effect of pesticides on inland
aquaculture water quality that the desirable range for TDS is
500–1000 mg/L (Abbassy, 2018).
• The recommended range for total hardness in inland
aquaculture is 75–150 mg/L while for total alkalinity is at a
similar range of 75–200 mg/L (Zweig et al., 1999;
• maximum permissible levels established by WHO and US EPA
for water used for inland aquaculture for arsenic, cadmium,
chromium,copper, nickel, lead and zinc are 100, <1.1, 100, 2000,
<100,<3.2, 5000 μg/L respectively (Abbassy, 2018).

10. Other Innovative Studies highlighted particles
used for Treating Aquaculture effluents

11. References
• https://onlinelibrary.wiley.com/doi/full/10.1111/raq.12617
• Pinho SM, David LHC, Goddek S, Emerenciano MGC, Portella MC. Integrated production of Nile tilapia juveniles and lettuce using biofloc
technology. Aquac Int. 2021; 29(1): 37- 56. https://doi.org/10.1007/s10499-020-00608-y
• Sara M. Pinho, J´essica P. Lima, Luiz H. David a , Magdiel S. Oliveira c , Simon Goddek b , Dalton J. Carneiro a,c , Karel J. Keesman b, , Maria
C´elia Portella. 2021. Decoupled FLOCponics systems as an alternative approach to reduce the protein level of tilapia juveniles’ diet in
integrated agri-aquaculture production. Aquaculture Volume 543, 736932: https://doi.org/10.1016/j.aquaculture.2021.736932
• Sara M.PinhoaRoberto Manolio ValladãoFloresbLuiz H.DavidaMaurício G.C.Emerencianoce1Kwamena K.QuagrainiedMaria CéliaPortella .
2022. Economic comparison between conventional aquaponics and FLOCponics systems. Aquaculture, Volume 552, 15 April 2022, 737987
https://www.sciencedirect.com/science/article/abs/pii/S0044848622001016
• Lawal A. Ogunfowora ,⇑, Kingsley O. Iwuozor,⇑, Joshua O. Ighalo and Chinenye Adaobi Igwegbe. 2021. Trends in the treatment of
aquaculture effluents using nanotechnology. Elsvier-Cleaner Materials 2 (2021) 100024.