How to do it?
Construction of ponds
Aeration and mixing is an essential feature determining the planning of the pond.
Most ponds have radial or elliptic water flow modes, concentrating the settled organic waste in the center. Ponds can be round (or close to it) or rectangular. The ponds should have a slope toward the hydraulic center, to create a sludge trap. An alternative design is a closed raceway, made by a partition (not necessarily a tight and rigid partition) in a rectangular pond. A low lying sludge trap should be made in the exit corner of the pond. Sludge traps should be equipped with a wide diameter drainage pipe
If possible, ponds should be lined. In soil ponds without lining, the intensive water flow can erode pond banks and add significant amounts of fine soil particles to the bottom sludge. In addition, the large amounts of organic residues sinking to the pond bottom will mix with soft mud and create a deep sludge layer that is hard to control. All this will generate anaerobic condition in the pond bottom failing fish (or shrimp) production. Lining can be made using plastic sheets (HDPE), soil – cement mixture or compacted Laterites.
Intensive BFT fish ponds carry a biomass of up to 30 kg/m3 and daily feed of up to 600g/m3. These ponds generate very high TSS and sludge that has to be drained daily. Pond size is limited by the ability to thoroughly well mix ALL points in the pond and effectively drain sludge. Typical size of tilapia ponds with a biomass of 20-30 kg/m2 is 50 m2 to about 1000m2 . Shrimp BFT ponds carry a lower biomass (up to about 2 kg/m3) lower feed ration and suspended solids. Typical size of such ponds is around 1 ha.