FR GRAND RESOURCES: February 2009

In today's organic food market there is a lack of organic cultured fish products. Organic catfish products could fill-up this gap. The project with catfish mainly focuses on the potential and certification of organic catfish cultured in closed recirculation systems, possible integrated with other agriculture activities.

Supply of seafood from ocean capture fisheries is declining due to over-fishing and pollution.
Demand for quality seafood is soaring due to population increase and health considerations.
Consumers everywhere want consistency in quality, safety and availability at the right price.

Aims :

Research and feasibility study organic catfish culture.
Integration of organic aquaculture with organic agriculture.
Design and define sustainable catfish aquaculture enterprise.
Developing standard of certification for organic catfish.
Certifying catfish farms, resulting in supplying of organic catfish product on the market.

FR Recirculation System (Biosystem)
Imagine the water is flowing from left to right ....

Imagine the red balls are ammonia excreted by the fish. Also imagine water is flowing over the biomedia from left to right. You can see lots of red ammonia molecules are flowing into the filter although they are dissolved in the water in reality. Look carefully and you will see dark grey Alfagrog biomedia underneath the coloured balls. Look even more carefully and you might see the oxygen bubbles also dissolved in the water. The ammonia mixed with oxygen in the water is continuously flowing across the biomedia (Alfagrog). The yellow bacteria can be seen sitting on the surface of the biomedia just waiting for ammonia and oxygen to come along.

At the point where the water meets the biomedia (ie where the bacteria live) the red ammonia molecules are broken down (oxidised is the correct term) by the bacteria which keep taking deep breaths of oxygen in order to complete the conversion of ammonia and nitrites to those blue molecules that you see starting to appear. These blue molecules are nitrates. You do not need to be a chemist to understand the next line but do take a moment over the next paragraph .

NH3 is converted by one type of bacteria to become NO2 this is converted by second and different type of bacteria to become NO3. All I want you to take notice of is that ammonia has no oxygen, nitrite has 2 atoms of oxygen and nitrate has 3 atoms of oxygen in its molecule. If the water did not have oxygen in then this conversion could not happen.

Notice the mixture of pretty colours in the middle of the picture this is where the conversion and intermingling action is taking place. You can possibly imagine lots of things are happening at the same time in this region.

The nitrates become the fertiliser for the plants and stay in the water until consumed by plants or pumped out of the pond with a water change.

You will notice that there are still a few red ball bits of ammonia left because the bacteria did not manage to get to them first time around circuit these get eaten next time or maybe even the next.
Just after feeding fish the red balls increase by an enormous amount and as such you will nearly always measure ammonia in the water shortly after feeding. However if the biofilter is mature and working well this is rapidly brought under control.

I have just described in simple terms what is called the nitrification cycle that occurs in all ponds and natural waterways.

At FR Grand Resources, we have develope our own prototype recirculation system known to us as FR Recirculation System (FRRS). In a recirculation system the culture water is purified and reused continuously. A recirculation system is an almost completely closed circuit. The produced waste products; non soluble waste, ammonium en CO2, are either removed or converted into non-toxic products by the system components. The purified water is subsequently, saturated with oxygen, returned to the fish tanks. By recirculating the culture water, the water and energy requirements are limited to an absolute minimum. It is however not possible to design a recirculation system as a fully closed system. The non-degradable waste products must be removed and evaporated water must be replaced. Still our recirculation systems are capable of reusing 90% or more of the culture water. To ensure good water purification, FRRS systems consist of a number of components with specific functions. The fish culture system must be able to :

1. Remove solid particles (waste, spilled feed)
2. Remove dissolved organic matter
3. Convert ammonium into the less harmful nitrate
4. Remove CO2 and add O2

In these culture systems the culture water is purified and reused, which results in an enormous saving of water and energy.