Outlet water treatment - Aquaculture Engineering

Outlet water treatment

If the outlet water is to be treated, this normally only includes equipment for removing particles and storing the sludge. This equipment should be placed as close to the production units as possible to avoid damaging the particles. The water must be treated as gently as possible before it enters this equipment. Normally the effluent water is treated in a separate department or building. It is important to have sufficient slope on the pipes from the production unit to the treatment plant to avoid having to pump because this breaks up the particles. The particle filter is normally of the rotating screen type with a mesh size of 90–100 μm. Outdoor settling ponds may also be used. However, phosphorus can be released from settling ponds.

Contamination of the inlet water by the outlet water must be avoided to reduce the possibilities for disease transfer. Therefore there should be no possibilities for direct movement of personnel between these departments. Neither should there be any possibilities for short circuits between the inlet and outlet pipes. If the inlet water is pumped from a lake or from the sea and the outlet water is sent back to the same source, it is important that short cuts and/or cross contamination are avoided. The inlet and outlet pipes must be spaced far apart both in the vertical and horizontal directions. Transport of the outlet water directly to where the inlet is placed by the main current must also be avoided.