Performance of plastic
biofilter media with different configuration in a water recirculation system
for the culture of Nile tilapia (Oreochromis niloticus)
Y.S. Al-Hafedh, A. Alam, M. Afaque Alam-2003
Aquacultural Engineering, 29(3-4): 139-154
Abstract:
Three kinds of locally available plastic biofilter
media with different configurations (plastic rolls, PVC pipes and scrub
pads) were evaluated for their efficiency in organic waste removal from the
effluents of an intensive recirculating tilapia culture system. A set of
three types of solid-removing filters consisting of screened sedimentation;
upflow sand as well as plastic bead filtration accomplished the mechanical
filtration. Values of critical metabolic wastes like total ammonia nitrogen
(TAN) (0.92 ppm) and nitrite-nitrogen (NO2-N) (0.22 ppm)
were found to be well within the acceptable limits, while other water
quality parameters in the culture water were also maintained within the
normal range by the filtration system. Removal rates of 3.46 g TAN/m3
per day and 0.77 g NO2-N/m3 per day, as well as
TAN and NO2-N removal efficiencies of 29.37 and 27.3%
respectively, were established to be the best for the plastic-roll biofilter
medium as compared to PVC-pipe and scrub-pad media. Percent removal of TAN
and NO2-N per pass of the biofilter (25.49 and 26.3%
respectively) and the specific TAN and NO2-N removal rates (43
and 9.6 mg/m2 per day) of plastic rolls were also found to
be superior to the other two biofilter media. Pieces of PVC pipes as
biofilter medium is recommended to be used in the biofilters in view of
their cheaper cost.
(Natural Resources and Environment Research
Institute, King Abdulaziz City for Science and Technology, P.O. Box 6086,
Riyadh 11442, Saudi Arabia, e-mail: yhafedh@kacst.edu.sa)