Nitrogen budget and effluent nitrogen components in aquaponics recirculation system

• Published in: Desalination and water treatment 2014, Vol.52 (4-6), p.744-752
• Main Authors: Endut, Azizah, Jusoh, Ahmad, Ali, Nora’aini
• Format: Article
• Language: English
• Subjects: Aquaponics recirculation system; Mass balance; Nitrogen budget; Passive denitrification; Passive nitrification
• ISSN: 1944-3986; 1944-3986
• DOI: 10.1080/19443994.2013.826336

In this study, the dynamics of nitrogen through aquaponics recirculation system was examined by developing a nitrogen budget. The model evaluated total ammonia nitrogen (TAN) production and removal in biofilters, identifying and quantifying the fate of nitrate nitrogen (NO3--N) and determining the system maximum carrying capacity. Of the nitrogen input into the culture tank via feed, 83.8% was recovered from different pool: 39.4% as fish flesh (harvested), 2.1% as mortalities, 34.7% as dissolved inorganic forms of nitrogen and 7.6% as total organic nitrogen. The remaining 16.2% of nitrogen unaccounted for likely was lost as nitrogen gas due to passive denitrification and as volatization of ammonia. Average TAN in the culture tanks was 2.08 mg/L. Under current condition, system loading with fish biomass at average of 68.5% of the maximum predicted. The hydroponic troughs removal efficiency averaged 60.4% TAN per pass. From TAN production, 88% was removed in hydroponic troughs, 11% by passive nitrification and 1% by water exchange. Under conditions of reusing treated effluent with residual TAN, the hydroponic troughs work normally, while TAN in the systems did not increase noticeably.