Lab- and pilot-scale photo-biofilter performance with algal–bacterial beads in a recirculation aquaculture system for rearing rainbow trout

Abstract Industrial aquaculture has proliferated due to increased world demand for fish and seafood. Aerobic bacterial biofilters typically perform the nitrogen abatement of wastewater. Recirculation systems (RAS) require nitrifying microorganisms developed in biofilter. Despite advantages these biofilters, there are disadvantages, such as time needed mature, decrease oxygen concentration, accumulation organic matter difficulty backflushing, among others. On other hand, microalgae effectively eliminate nutrients-pollutants, consuming inorganic carbon, nitrogen, phosphorus balancing soluble oxygen, conditions not attributable biofilters. The current study used a photo-biofilter determine depuration capacity an immobilized co-culture microalga Tetradesmus dimorphus bacteria isolated from Salmon RAS. Bacteria frorm genera Flavobacterium , Microbacterium Raoultella Sphingobacterium Pseudomonas were identified. Biofilters tested sequential batch (lab-scale; 2.85 L) continuous mode (pilot-plant scale; 120 attached RAS system rearing rainbow trout. algal–bacterial community structure was studied using 16S rRNA gene sequencing. Results showed that at typical loading rates, could simultaneously remove ammonium, total ammonium (TAN), nitrate phosphate. Moreover, evaluated removed TAN daily, average 1.18 kg per m 3 beads. Graphical