Nutrient uptake by microalgae in tap water, wastewater and copper (Cu) amended wastewater

Abstract

In this work the ability of different strains of microalgae to remove nutrients from wastewater was studied. Ammonium, nitrate, phosphate concentration, pH and conductivity were measured throughout the experiments. Batch system was used for growing the eight different strains of algae in mono as well as combined culture by using substral (an artificial fertilizer) as nutrient source. Algae strains that showed better growth rate were chosen from the growth culture and used in the first batch experiment run in which growth medium was changed from tap water to wastewater. The nutrient uptake decreased over the two weeks test period. In a second batch experiment run the waste-water was amended with Copper but otherwise had the same setting as the previous run. Nutrient concentrations for ammonium and nitrate and phosphate also showed a decreasing trend throughout the two week time of the experiment. In the last experiment run the Algae Turf Scrubber (ATS) system was used to test the nutrient removal ability of algae in a continuous process from a Copper amended wastewater. The wastewater used in the experiments was from the municipal wastewater treatment plant of Tampere. The ATS system removed efficiently –below detection limit- the P within two days of testing. Nitrogen concentration decreased as well within the first two days, with 40% but increased after that. The removal of nitrogen needs to be studied in further studies.