Nitrogen budget and effluent nitrogen components in aquaponics recirculation system

• Main Authors: Azizah, Endut, Ahmad, Jusoh, Nora’aini, Ali
• Format: Article
• Language: English; English
• Published: 2014
• Subjects: SH Aquaculture. Fisheries. Angling
• Online Access: http://eprints.unisza.edu.my/4839/1/FH02-FPBSM-14-00328.pdf; http://eprints.unisza.edu.my/4839/2/FH02-FSTK-14-00811.jpg; http://eprints.unisza.edu.my/4839/

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 (NO 3 -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.