Comparison of biofilter efficiency and biofilter submerging time for improve water quality in aquaculture

Abstract

The objectives of this research were to evaluate type of media on surface bacterial attachment and inorganic nitrogen compound removal and to evaluate optimal time of biofilter submerge in water for high efficiency water treatment. Completely randomized designs were used in trials with 3 replicates. The attention factor was biofilter type including bioball, roll net and fibrous rope. Zero point one square meter of each biofilter was submerged in one liter of aquacultural water in plastic tank. Total marine bacteria, nitrifying bacteria and water quality parameters as total ammonia, nitrite and nitrate were collected every 5 days. The experimental period was 20 days. Results illustrated that bioball could improve water quality and had significantly (P < 0.05) higher number of total marine and nitrifying bacteria than the others. Number of total marine bacteria and nitrifying bacteria at 15 and 20 days had significantly (P < 0.05) higher number than the day before. Ranges of total ammonia, nitrite and nitrate concentration in this research were 0.06 - 0.64, 0.01 - 0.43 and 0.02 - 0.13 mg-N/L, respectively. All results of this study revealed that optimal time of biofilter submersion in water was 15 day bioball could improve water quality for aquacultural closed recirculating water system.