Jacky Foo [foo@swipnet.se] asked
> If we compare the above scenario operation to that of a conventional
> hydroponic lettuce production of the same scale, what would the costs
> of  chemicals/plant nutrient input costs ?
>
> Could it be that the use of effluent would be require less and low
> costs  for chemicals/plant nutrients ?

Jacky,

We have completed an economic analysis of our system and nutrient costs are
about 0.5% of the combined operating costs. Labor,
energy, a manager, and packaging materials account for about 75% of the
combined operating costs and another 20+% in fish feed, seed costs,
overhead, and maintenance. I don't have the nutrient costs for a
conventional hydroponic operation, but although they are significantly more
than ours, since we get most nutrients from the fish, I'm sure that they
are still insignificant compared to the costs I have listed above. When you
compare our system with standard water treatment technology, the capital
costs are similar, our operating costs are significantly more, but you make
money while cleaning the water and growing plants. So you can actually make
a profit while treating the water, instead of just incurring costs.

> >In this fish production system, solids are removed with a triangle
> >filter. The triangle filter is able to remove about 80% of the P
> > excreted by the fish with the biosolids, leaving about 20%
> > of the P in the effluent.
>
> what do you do with the filtered material, is there any use for this
> material ?

Regarding the solid organic material, we are working on a type of
composting system.

        Paul