|Activation of a nitrifying biofilter using a pH controller (abstract)|
Drouin, H.; de la Noüe, J.; Lavoie, M. (1989). Activation of a nitrifying biofilter using a pH controller (abstract), in: De Pauw, N. et al. (Ed.) Aquaculture: a biotechnology in progress: volume 1. pp. 1069
In: De Pauw, N. et al. (Ed.) (1989). Aquaculture: a biotechnology in progress: volume 1. European Aquaculture Society: Bredene, Belgium. ISBN 90-71625-03-6. 1-592 pp., more
|Available in|| Authors |
|Document type: Conference paper|
|Authors|| || Top |
- Drouin, H.
- de la Noüe, J.
- Lavoie, M.
The activation of a biofilter is a slow process that generally requires between 4 and 8 weeks. The sole energy source of autotrophic nitrifying bacteria (oxidation of ammonia and nitrite) is a low-energy yielding process. The nitrifiers are thus slow growers. Our goal was to establish within the shortest possible time, a stable population of nitrifying bacteria, capable of performing upon connection to a full tank of fish. Trickling filters filled with polystyrene support (220m².m-3) were inoculated with an enriched culture prepared by incubation of sludge from a previous filter in Nitrosomonas medium (Sato ). After the exhaustion of the ammonia initially added, the filters were continuously injected with ammonia (NH4Cl), simulating a given fish load. A constant pH (8.5) was maintained by the automatic addition of sodium carbonate with a pH stat. The daily parameters followed were: NH4+, NO2-, NO3-, dissolved oxygen (DO). alkalinity, Na2CO3 consumption, and hardness. Free and immobilized nitrifiers (Nitrosomonas sp.. Nitrobacter sp.). heterotrophic bacteria, and denitrifiers were enumerated. After 6 days, the NH4+ concentration decreased below 0. 7mgI1 with a maintenance average of 0.4:tO 18mgI1. It took 8 days for NOz- to decrease below 0.5 mg.l-1 (average = 0.1:tO.13mg.l-1). The nitrate concentration reached 86.2mg.l-1 Alkalinity (as CaCO3), hardness (as CaC03), and dissolved oxygen (DO) were relatively stable with respective mean concentratioons of 170±34mg.l-1, 197±20mg.l-1 and 8.3±0.3 mg.l-1. Approximately 10g of alkalinity (as CaC03) was consumed for every g of ammonia (NH4+) injected. By using an inoculum enriched for nitrifying bacteria. and maintaining the pH at 8.5 with Na2C03 we succeeded in activating a nitrifying trickling-filter in approximately 8 days. This research was supported by FCAR-Equipe and CRSAQ grants.