Resource recovery and phytoremediation of fish-processing effluents using halophyte plants

Abstract

The reuse of saline effluents from the fishing industry is an appealing alternative for halophyte cultivation. The objectives of this study were to compare the growth of Atriplex lampa in hydroponics using fish-processing effluents (E) versus a control solution (Co), and to assess its potential for effluent phytoremediation. No significant differences between treatments were detected in the (fresh and dry) weight of the plants, shoots, and roots, or in the concentrations of total chlorophylls and carotenoids. Total N in leaves, stems and roots was lower in E than in Co (p < 0.05), likely due to the minor availability of inorganic N in the fish-processing effluent compared to the control. Conversely, the nutrient efficiency ratio (NER) for N was higher (p < 0.01) in plants from E than in Co, indicating an increased efficiency with which plants exposed to fish-processing effluent convert N resources into dry mass. Hydroponic cultivation reduced the effluent electrical conductivity (EC, 29.6%), Biochemical Oxygen Demand (BOD5, 93.7%), Chemical Oxygen Demand (COD, 73.2%), NH4+ concentration (63%), and odor. The successful integration of A. lampa cultivation, a fodder plant used for ecological restoration of degraded drylands, with hydroponics, offered a valuable model for reusing and remediating fish-processing effluents.