Kasidit Nootong and Sorawit Powtongsook

pp. 53 - 59

Abstract

This experiment assessed the performance of submerged fibrous nitrifying biofilters (SFNBs) to carry out the zerowater exchange tilapia cultivation. Without biofilter cleaning, the SFNBs (21 m of biofilter length) were susceptible to
hydrogen sulfide production when operating beyond the aquaculture density of 13.62 kg/m³
. The SFNBs were able to
maintain total ammonia nitrogen (TAN) and nitrite below 1.0 mg N/L throughout the experiment and could handle inorganic
nitrogen loading as high as 38.6 mg N/L/day when the solid removal from biofilters was performed biweekly. Ammonium
degradation rate measured at the end of this study was 380±66 mg N/m2
/day for biofilters subjected to cleaning. A significantly lower rate of 41.4±2.86 mg N/m2
/day was associated with biofilters without any solid removal. Finally, the SFNBs
should be attractive for budget-limited farmers since they are simple to build and operate and can provide alternatives to
cage-cultured systems.