Activation of a Nitrifying Biofilter for High Density Fish Culture

Abstract

When a reuse water system operates at high fish loadings and recirculation levels, a readily perofrming biofilter is of utmost importance. The present work aims at reducing the colonization time of nitrifying bacteria with the intention of creating a fully operational trickling biofilter upon the introduction of a substantial fish load into the system. A technique is developed by which the future fish biomass is simulated continuous injection of ammonium salts (25.5 ± 2.6 g H-NH₄ ⁺/m³ of iofilter media (432 to 1411 ky fish/liter per minute of makeup water) with a sustaining water quality. With a pH mainained between 9.0 and 8.5, a hydraulic loading rate of 130 m³/m²/d. inorganic nutrients and an inoculum of active nitrifiers, fully reliable biofilters were obtained within 9 days. The role of alkalinity, inoculum, and mineral nutrients is also discussed.