Microalgal biofilms for wastewater treatment

The objective of this thesis was to explore the possibilities of using microalgal biofilms for the treatment of municipal wastewater, with a focus on the post-treatment of municipal wastewater effluent. The potential of microalgal biofilms for wastewater treatment was first investigated using a scenario analysis. Then biofilms were grown on wastewater treatment plant effluent in horizontal flow cells under different nutrient loads to determine the maximum uptake capacity of the biofilms for NO3 and PO4. Subsequently, microalgal biofilms were grown in a vertical laboratory-scale biofilm reactor. The effect of harvesting and biofilm thickness on the biomass production and nutrient removal was investigated. The biofilm reactor was taken outdoors and a vertical pilot-scale biofilm reactor was evaluated as post-treatment of municipal wastewater in a pilot-study. Finally, symbiotic microalgal-bacterial biofilms were investigated for full treatment of (pre-settled) wastewater.