BIOREMEDIATION OF WASTEWATER ORIGINATE FROM AQUACULTURE AND BIOMASS PRODUCTION FROM MICROALGAE SPECIES - NANNOCHLOROPSIS OCULATA AND TETRASELMIS CHUII

K. N. Velichkova, I. N. Sirakov

Abstract: The cultivation of microalgae in wastewater leads to the removing of nutrients and at the same time, produces biomass which can be further exploited as a biofuel. At the same time, Tetraselmis sp. and Nannochloropsis sp. have a high nutritional value, and for this reason they have been widely used as a food supply in the aquaculture industry for hatchery grown herbivores. The aim of current study was to compare the biomass accumulation of two microalgae species Nannochloropsis oculata and Tetraselmis chuii cultivated in wastewater originate from recirculation aquaculture system (RA S) and explore their abilities for nitrogen and phosphorus compound removal. A bioreactor consisted of 500 ml Erlenmeyer flasks, containing 250 mL of wastewater from semi closed recirculation aquaculture system. The cultures were maintained at room temperature (25-27ºC) under a fluorescent light with a light:dark photoperiod of 15 h: 9 h, with sterile air containing 2% (v/v) CO2. Optical density, chlorophyll and carotenoids were measured for the biomass evaluation for a 10 days growth period. In our study N. oculata removed 78.4% of total nitrogen and 92% of nitrate. At the end of experiment for T. chuii cultivation in wastewater, phosphorus decreased by 79%, which was by 26.7% higher, compared to that of the phosphorus removal rate of N. oculata.

Keywords: biomass; Nannochloropsis oculata; RAS; Tetraselmis chuii; wastewater

Date published: 2017-10-26