Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 15:15:0020/09/2023 15:30:00Europe/ViennaAquaculture Europe 2023RESOURCE RECOVERY AND INCREASING PRODUCTIVITY IN A SUSTAINABLE INTENSIVE NEAR ZERO WASTE ASSIMILATION BASED RECIRCULATING AQUACULTURE SYSTEMS (AsRAS)Schubert 1The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


Amit Gross1 , Uri Yogev2 , Ze Zhu1,3, Dina Zilberg4

2 National Center for Mariculture, Israel Oceanographic and Limnological Research Institute, 88112 Eilat, Israel ; 3 Mathematical and Statistical Methods - Biometris, Wageningen University and Research, P.O. Box 16, 6700 AA Wageningen, Netherlands ;

 Email of presenting author:




Food security, specifically in water-scarce regions, is a local and global aim which requires innovative solutions. Assimilation based recirculating aquaculture systems (AsRAS ) such as aquaponics, algaponics and bacterioponics can be such a sustainable solution. All AsRAS involve the integration of  conventional recirculating aquaculture system (RAS) with assimilation based reactor in a symbiotic arrangement. In aquaponics for example, fish excretions are assimilated as a nutrient source for vegetable production (Zhu et al., 2022) , where in algaponics and bacterioponics it would be replaced by macro or micro algae and bacteria respectively. As a result, the assimilation of the fish waste by plants or bacteria treat the water, and enables its recirculation back to the fish tank. This practice allows for extremely high efficiency in the use of water and nutrients, greatly limits the discharge of pollutants and recovers or saves a lot of energy  (Yogev and Gross, 2019) . 


In recent years w e have developed  three different AsRAS  that are operated on fresh or brackishwater in multi-loops near-zero waste setups. The systems include separate loops for fish production (RAS) and for the assimilation organism growth which facilitate optimal conditions for each crop. In addition,  in some systems  two separate  treatment loops are used to treat the solid waste (e.g. from  fish and inedible plant bits) by anaerobic digestion, producing nutrient-rich  supernatant which is good for plant growth and energy via biogas .


In all tested systems f ish stocking density reached  up to 80 kg/m3  with typical density of approximately 50 kg/m3. Feed (45% protein content) was applied daily at 2% of body weight. Typical fish performance was observed with a survival rate >95 % and feed conversion ratio ranged between 1.1-1.4. Significant energy saving was demonstrated; from >80% in the aquaponics  system and 50% in the bacterioponics/biobloc based RAS. C arbon sequestration was 1.4 higher than the feed carbon in the aquaponics system , which reduced the carbon footprint  of typical RAS by 64% where  similar or even higher  reduction  is expected  for the algaponics -based AsRAS. Moreoven in all of the studied AsRAS significant reduction of nitrous oxide was recorded when compared to traditional RAS. 

Th ese stud ies are among the  first to demonstrate highly efficient AsRAS  production with near-zero water and waste discharge and with  significant  energy recovery  or savings. We postulate  that AsRAS systems have a great potential to replace the traditional nitrification-denitrification based RAS.


Yogev, U., Gross, A., 2019. Reducing environmental impact of recirculating aquaculture systems by introducing a novel microaerophilic assimilation reactor : Modeling and proof of concept. J. Clean. Prod. 226, 1042–1050.

 Zhu, Z., Yogev, U., Goddek, S., Yang, F., Keesman, K. J., Gross, A. 2022. Carbon dynamics and energy recovery in a novel near-zero waste aquaponics system with onsite anaerobic treatment. Science of The Total Environment, 833, 155245.