Phosphorus (P) runoff from wastewater and agriculture is one of the main causes of eutrophication, where > 100 μg P/L is considered sufficient to promote eutrophication. Chemical precipitation and coagulation are the most commonly used methods for removing phosphorus in the wastewater post-treatment phase. However, the implementation and operating costs of these methods are high, and their use generates additional waste. The use of algae for wastewater treatment is recognised as a cheaper and more environmentally friendly alternative, especially in small wastewater plants (PE<2000). Microalgae can efficiently remove nitrogen and phosphorus from wastewater at low organic-carbon levels, and the biomass produced is a raw material for further production of biofuel or soil enricher. However, because of slow biomass growth and nutrient consumption, these technologies take up a lot of space. The aim of the project is to demonstrate the application of a cyclic-operation photobioreactor for accelerated phosphorus reduction to very low levels, using the ability of algae to consume increased amounts of phosphorus under certain conditions.