In aquaculture, recirculated aquaculture systems (RAS) show potential circularity due to their capacity to reutilize water and concentrate nutrient-rich effluents While successful implementation of circular production has been demonstrated in freshwater RAS with aquaponic systems, effective nutrient recycling in marine RAS is challenging . The high salinity levels in marine RAS effluents exceed crop tolerance and municipal wastewater treatment limits.
In response to these challenges, algae emerge as a promising and cost-effective solution for capturing dissolved nutrients in marine aquaculture . Their efficient uptake and assimilation of key nutrients, including nitrogen, phosphorus, and carbon, align closely with the nutrient composition of RAS effluents. Despite nitrogen’s proven bioavailability for algae cultivation from RAS overflow water, the bioavailability of phosphorus, carbon, and micronutrients in RAS sludge remains a significant hurdle. While carbon recovery from waste has been explored, the recovery of dissolved phosphorus has not been fully elucidated.
This study investigates the redox effect on nutrient solubilization as part of a broader project aiming to the develop both a method and a biological reactor concept to enhance nutrient solubilization from marine RAS sludge to support Ulva sp. growth. Key parameters, including ORP, dissolved oxygen, various nitrogen and phosphorus species, iron, manganese, acetate, and chemical oxygen demands, were monitored to understand the effects of redox on their solubilisation . The nutrients were chosen as the nutrients affecting the most Ulva growth based on the literature.
The outcomes of the study , currently undergoing analysis , will be showcased in the forthcoming presentation.