Growth of Tetraselmis suecica in a tubular photobioreactor on wastewater from a fish farm

Abstract

Wastewater from a fish farm was remediated in a continuously operated tubular photobioreactor in which Tetraselmis suecica was cultured. The N and P removal efficiencies and the productivity of T. suecica growing on the wastewater were determined. Possibilities to optimize the productivity by adding extra orthophosphate were investigated. At a biomass concentration of 0.5 g L(-1) on only wastewater, the N and P removal efficiencies were 49.4% and 99.0%, respectively. When extra phosphate was dosed to the wastewater, a 95.7% N removal efficiency and a 99.7% P removal efficiency could be reached at a biomass concentration of 1.0 g L(-1). This also resulted in significantly higher average net volumetric productivity ranging from 0.35 g L(-1) d(-1) at a biomass concentration of 0.5 g L(-1) to 0.46 and 0.52 g L(-1) d(-1) at biomass concentrations of 0.75 and 1.0 g L(-1), respectively. This study shows the feasibility of an integrated multi-trophic aquaculture approach where wastewater from the fish farms is used to produce feed for juvenile shellfish at high productivity and constant quality.

Keywords: Productivity; Removal efficiency; Tetraselmis suecica; Tubular photobioreactor; Wastewater.