Thursday, October 26, 2017

27/10/2017: Fish farm water treatment: New multi-approach for application of sodium ferrate

by Mr Gianluigi Negroni and Mr Federico Rivalta

Aquaculture is known worldwide to play an important and promising role in food security

It provides great business and livelihood opportunities to many communities. As better expressed by management expert and economist Peter Drucker, “Aquaculture, not the Internet, represents the most promising investment opportunity of the 21st century.” 

Image credit: Norsk Havbrukssenter on Flickr
(CC BY-SA 2.0)
Ferrate(VI) (FeO42-) is proposed as a viable means for more cost-effective aquatic animal farming. Tests done using ferrate(VI) have showed its effectiveness in wastewater disinfection.

Many studies have been conducted on the use of ferrate(VI) as disinfector, oxidiser, and coagulant, as well as for the removal of medicines, ammonium, cyanides, sulphides, phosphates, arsenic, estrogens, anilines and phenols in water and wastewater treatment.

However, limited publications have been made on the use of ferrate(VI) in aquaculture. Hence, this research will further demonstrate its most promising technological characteristics, and a new-patented machinery model will be presented in this paper.

As seen in Figure 1, shrimp-farming production is concentrated in Asia. Forty-four percent of fish stocks have been heavily exploited.

Farm-raised fish have the lowest feed conversion ratio (estimated feed required to gain one pound of body mass) compared to other farmed animals, and will likely increase exponentially in the coming years compared to fish from wild catch.

It is clear that there will be an increase in aquaculture activities globally, but space and water resources will continue to be limited, hence, intensive and efficient aquaculture systems are all the more needed.

Open and closed systems
Modern aquaculture systems could be divided into two main types: open and closed systems. In open systems, used water is discharged into the environment. In closed systems, a part (and rarely all) of the used water is recirculated after specific treatment.

In the first type, solids and dissolved nutrients are discharged into the environment.

In the production of aquatic animals, common wastes are composed of:
• Nitrogen (N)
• Phosphorous (P)
• Carbon (C)
• Orthophosphate (PO43-)
• Soluble waste – carbon dioxide (CO2)
• Ammonia (total amount nitrogen)
• Residues and trace elements (antibiotics, heavy metals, disinfectants)

To reduce the negative impact from wastes, common applications include the introduction of:
• Bacteria that degrade ammonia into urea and nitrate (NO31-)
• Plants that transform waste into biomass (bioremediation)
• Micro and macro algae that use the sun and then transform waste into biomass           

Moreover, the pathological area is also a very interesting area of ferrate use. These applications have their own set of advantages and disadvantages.

Moreover, ferrate(VI) is an easy, readily available and affordable material. This paper presents some patented equipment for ferrate(VI) production and utilisation in coagulation, chemical oxidation and disinfection of water and wastewater treatment.

Figure 2 shows the different disinfection and oxidant capabilities of common water and wastewater treatment chemicals. Until now, there are only a few large-scale patented equipment are being tested—Ferrate (VI) efficacy has already been tested and demonstrated for disinfection against common aquaculture virus, spores, bacteria and parasites.

Ferrate(VI) is also very effective in degrading heavy metals, PCBs, pesticides, antibiotics and other residues thus is considered very useful in aquaculture. It is well known that diseases from bacteria, virus and parasites provide problems particularly to the aquaculture industry (finfish, crustacean and others), affecting food security and causing economic losses.

Climatic change is also exacerbating these losses. The new ferrate technologies could be considered as an important mitigation and be adapted as a strategy for combating farm disease vulnerability and risks. Ferrate(VI) is not a biocide and can be safely used in the aquaculture industry.

Read the full article and view tables, HERE.

The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
magazine International Aquafeed which is published by
Perendale Publishers Ltd

For additional daily news from aquaculture around the world: aquaculture-news

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