All RAS applications, including Silver Perch
RAS, that I have had the pleasure of inspection, are top heavy in design.
Sure they are shiny and tech savvy however, they lack the simple necessities
of longevity so overlooked by all RAS applications that I wonder if they have
ever actually been aquatic farmers in any commercial sense. I worked at one,
in southern NSW, for just one day before quiting. The stench and accepted
mortality were as disgusting as the metal decay was amazing. The entire multi-million
dollar project would not see five years of operation. No profits there I am
afraid. So I designed the POD System based on commercial viability.
The POD System is entirely flexible to tank
design or pond layout. The same rules of filtration apply so the design can
be altered to suit species, quantity and available land. My cheapest tank
design consists of a rolled corrugated iron oval with a commercial liner.
It has a ten year life span on the liner and 20 years on the frame. So, a
100,000 litre tank costs about $1500.... Ten tanks gives you an awesome farm
for $15,000 in culture tanks. I think that is something special, even if it
is my own design.
May I suggest a new approach based on what you
wish to achieve? Then build a pilot scale version to 'acclimatise and educate'
yourself to fish farming methods and procedures before expanding out. Believe
me it is the safer way to successful aquaculture.
Many decisions depends on where you are and
the viable culture species available to you.
The POD design RAS is, in my observed opinion,
the best RAS design as it removes much of the labour and maintenance issues
associated with normal RAS. It also produces a far superior fish product in
terms of flesh texture, growth and reductions in disease issues.
Most importantly, the design is based on achieving
the highest return due to the above reductions in operating and maintenance
costs as well as providing much more pleasant environmental surroundings for
The thing with RAS thinking is; that
you need sophisticated technology and mechanisation. I know this to be
wrong. Nature has been purifying water for a very long time. It's efficient
and its free. You do not need drum filters nor indeed any mechanisation as
you will see from the pic above.
There are two RAS units of 30 tonne
each. They operate on one 3.5 kilowatt pump each. That is all the power requirement....
Oh you will probably need a backhoe or excavator to clean the filters once
every second year.
Now here is the thing. RAS systems
drive people mad. They are extremely stressful, costly and DO NOT make money.
Unless of course you have friends in the government who support you with grant
funding. It has never been my privilege and indeed Fisheries would not even
acknowledge the POD RAS system existed even though it could turn
over 30 tonne per 18 months with one labour/management component. The words
simple, successful and sustainable don't seem to mean much to the Dr Plod’s
of DPI Fisheries. After all there has not been a new aquafarming
permit in NSW or Queensland in 15 years. So, why do we pay millions for aquafarming
POD stands for Prodigious Organic Diffusion.
(very large form of organic reduction)
The filtration process has three major steps.
Firstly a ‘drum filter' or mechanical filtering stage ultising only
velocity reduction to remove particles.
Secondly, a nutrient stripping stage. The farm
in the pic used water hyacinth plants, incorporated into the mechanical filter,
to absorb the excess nitrogen and other nutrient excess. However, this stage
could easily incorporate an aquaponics stage. It is the same application
except the hyacinth plants created several tonnes of high nutrient compost
and not a crop.
And thirdly, any remaining nutrient was removed
through a two stage biological filter. Basically 20 tonnes of gravel with
integrated plumbing. Simple yes but the water on the down side of the bio
filter was drinkable..... If that is not a first nothing in aquaculture
is...in 1987.... :-)
And yet the design has failed to gain any foothold
in the new RAS industry. In a world attracted to shiny bobbles,
muddy ponds don't cut the mustard. It is indeed a sad lesson in life that
a species and size variable design, that could have gone global in application,
simply dried up in ignorance.
I had researched and developed a relaxed aquafarming application
whereby daily labour was reduced to feeding and observation. Such simplicity
does not require constant water analysis. The system is self-monitoring and
self-buffering over many months.
The pumping was automatic by timer to maintain
a constant head and gravity supplied the aeration. If aerators were added
I suspect an increase in biomass loading by maybe 50%. But then, that is not
the point of POD RAS. Health, quality, performance and disease free statis
In my opinion, the commercial point, of POD RAS,
is to generate a sustainable profit without being chained to the wheel. To
be able to enjoy the process of aquafarming with a system able to
function for at least 10 to 15 years without maintenance. The site above achieved
Email Kel to find out more............. firstname.lastname@example.org