RAS Plan

RAS Plan

Recirculating Aquaculture System or RAS is a new system for rearing fish. RAS usually is a close system which allowed farmers to control the environment inside their tanks around the year. However, the set up cost is quite bit expensive compare to other system such as pond or cage culture. If this system was manage with care and good it will give good profit to the owner for production of their expensive fish such as Kelah or Koi. RAS is a aquaculture system which complex and if you interested to built this kind of system, time management and discipline is important.

I was given a task to design a system using own idea. Below are several designs before I make a good design at last.

(1)

If we can see above, this kind of design is quite complex. This kind of design can culture many fish with high capacity in one time but the cost to set up this design will need many tools and not cost effective.  The design also quite messy and complex need more compartment. The existing of a filter drum in each tanks also not effective (b). the pressure to bring the water from fish culture tanks out to drum filter needed more pump and not cost effective. Then i change into second design.

(2)

This is my second design after realize a lots of not effective design in the first one. This design is more customer friendly and use small area only. After looking for compartment/drum that effective in removing sludge and urea existing in the rearing tanks. I found that Drum filter (g) is the best one. Drum filter can filter all kind of waste from the tanks even small particles and produce crystal clear water without wasting a lots of water and effective. This filter can run automatically and no need to pump out the water everyday. This situation will save your time, labour and energy. Drum filter in commercial type not available in Malaysia but need to export from Indonesia. There are some expert that can built this kind of filter and import by YTL group to sell to their customer in Malaysia. After long discussion with them we decided to buy it with acceptable price around RM 9,000-10,000 for one drum filter to use for 6-8 tanks 3 tonne water.

The importan compartment in set up RAS sytem is biofilter (f). It like the heart of RAS where mechanical and biological in a place. This filter can treat the water from toxic which produce by fish excretion and sludge. Ammonia and Nitrite is a dangerous material produce from fish excretion and it is a dangerous material that will cause fish die. Inside the biofilter exist bacteria such as Nitrobacter, Nitrosomonas, Nitrococcus and others which can treat the water naturally. Microbead/ substrate which needed in a filter for a place where the bacteria attach and propagate the good bacteria. Buble bead is a good types of substarte for maximum water treatment. The biofilter also imported trough YTL group and actually from US. The price around RM 19,000-20,000 per unit enough for a system. 

If think back i should maximize the area usage and i plan to add 2 more tanks and my supervisor order me to change into raceway design such as below.

(3)

But for me i'm not prefer using raceway tanks because it not area effective and I propose to use round tanks. The side and base material usage to make fiberglass is hard and will injured the fish because Kelah is quite extreme. I propose to use material that more flexible such as polyethylene/HDPE round tanks.

Continue....