Biological Nitrogen Removal Database

A manually curated data resource for microbial nitrogen removal

Freshwater systems

Experimental setup

Influent:Aquaculture wastewater

Denitrification system:Recirculating aquaculture systems Heterotrophic Denitrification

Denitrifying reactor:Packed bed


Culture taken from:nan

Organism (s) cultured:Eel


Electron donor:Methanol

Electron acceptor:Nitrate

Experimental Information

Input NO3-N (mg/l):150.0

Nitrate removal rate (mg NO3-N/l/h):1.8

Denitrification rate (gNO3-N removed/m3/day):43.0

Microorganisms identified:nan

Molecular tools:nan

Information about Article

Major findings:The closed recirculating system applied in this study brings environmental load close to zero and has the potential to be applied in freshwater systems as a novel aquaculture technology.

Authors:Suzuki et al., 2003

Title:Performance of a closed recirculating system with foam separation, nitrification and denitrification units for intensive culture of eel: towards zero emission

Pubmed link:None

Full research link:Link

Abstract:The development of a closed recirculating aquaculture system that does not discharge effluents would reduce a large amount of pollutant load on aquatic bodies. In this study, eel were reared in a closed recirculating system, which consisted of a rearing tank, a foam separation unit, a nitrification unit and a denitrification unit. The foam separation unit has an inhalation-type aerator and supplies air bubbles to the rearing water. The growth of eel, which were fed a commercial diet, was satisfactory, with gross weight increases of up three times in 3 months. The survival rate under the congested experimental conditions was 91%. The foam separation unit maintained oxygen saturation in the rearing water at about 80%. Furthermore, fine colloidal substances were absorbed on the stable foam formed from eel mucus and were removed from the rearing water by foam separation. Ammonia oxidation and the removal of suspended solids were accomplished rapidly and simultaneously in the nitrification unit. The ammonia concentration and turbidity were kept at less than 1.2 mg of N per litre and 2.5 units, respectively. When the denitrification process was operated, nitrate that accumulated in the rearing water (151 mg of N per litre) was reduced to 40 mg of N per litre. The sludge was easily recovered from the nitrification and denitrification tanks, and the components were found suitable as compost. Based on these results, the intensive aquaculture of freshwater fish such as eel can be achieved using a closed recirculating system without emission.