Building Diagram
Probes in each tank
monitor oxygen levels and system temperature. This
information is relayed to a computer in the lab which
displays each tank's information (shown below).
With this
computer we can track oxygen and temperature trends as well as set
tolerable
thresholds for these parameters. If
levels go outside of these thresholds, staff will be alerted to the
problem by
cell phone and audible alarm. At least
one employee is on-site to respond rapidly to alarms 24-hours/day. |
Currently, “growout” fish are housed in a greenhouse containing 12 tanks holding a capacity of 8000 gallons or 30,283 liters per tank. There are 3 tanks per system and the schematic is shown to the left.
The drain water from each 3-tank system collects into a main drain and flows into a surge tank. The water then travels into a drum filter that filters out particulates smaller than 60 microns, and proceeds into one of two biofilter tanks (shown above). The tanks are filled with a plastic “pasta-like” media similar to that used in the hatchery. The water then flows into a pump tank where it is aerated, treated with ultraviolet light, and pumped into oxygen cones. The ultraviolet lights are found in the pump tank, or in an in-line tube after the pumps. The oxygen cones provide an environment where oxygen gas can be efficiently dissolved into the water before it travels back to the tanks. The systems are not identical (i.e., aeration versus no aeration and different pump size) because we are trying to determine which system’s engineering is the most efficient. The water cycles through the system at a rate of once per hour. New water is brought into the system at a rate of only 5-10%/day, and no water is discharged off site. Discharged water travels to a sump outside the greenhouse, where it is pumped into on-site effluent ponds. The water then percolates down through the ground where it is treated naturally. |