Aquaculture effluents as fertilizer in hydroponic cultivation : a case study comparing nutritional and microbiological properties

Abstract: This paper evaluates the prospects for utilizing aquaculture effluents as a nutrient source in organic hydroponic, as is the case in aquaponics. The development of organic hydroponics is dependent on replacing synthetic fertilizers with organically derived nutrients, such as those found in aquaculture effluents. Also, in hydroponic cultivation the establishment of a plant pathogen suppressive micro flora is part of the plant protection strategy. Therefore, both nutritional and microbial qualities of aquaculture water and organic hydroponic nutri-ent solution were analyzed and compared. Results showed both aquaculture water and or-ganic hydroponic solution to be deficient in a number of essential elements, although or-ganic hydroponic solution was closer to recommendations. The organic nutrient solution had the highest densities of aerobic bacteria as well as fluorescent pseudomonades. Levels of fluorescent pseudomonades in aquaculture water were significantly lower after passing through the biofilter. Qualitative analysis of microorganisms in an actual aquaponic farm would help to better understand the composition of the micro flora in this unique environ-ment and its implications for nutrient cycling as well as plant health.