Design keys of a recent recirculating facility built in Chile operating with fluidized bed biofilters

The fast evolution of recirculation systems for salmonids has challenged the engineering companies to develop new and better design and engineering practices, to improve the water quality and system flexibility. One of the major factors that affect the water quality parameters is the total suspended solids produced within the system. The design of water flow from the water inlet into the culture tank down to the effluent pipeline and the water filtration unit, will determine a system's performance. Two recirculating systems for 250 and 1500 m3 have been designed and built applying specific design keys focused in good solids removal, system removal exchange, piping size and layout, filtration process, biofiltration units, gas balancing and CO2 removal, oxygenation devices, and disinfection process. All these treatments have been designed and built for both facilities, and they are currently operating with very good results. Both facilities are in separate isolated buildings but in the same hatchery site. They share a common heat pump unit that delivers chilled water to the incubation room, and the makeup water is from several wells on site. This paper describes the main design keys used under this project focusing on the small recirculation system (250 m3).