Assessment of inorganic nitrogen and phosphorus compounds removal efficiency from different types of wastewater using microalgae cultures

Abstract

The efficiency of ammonium nitrogen (N-NH4+) and phosphate (P-PO43-) removal from wastewater with different loads of these nutrients was evaluated using Chlamydomonas reinhardtii (Chlorophyta) and Oscillatoria neglecta (Cyanophyta/Cyanoprokaryota). In addition, functional characteristics of the microalgae under the studied conditions were determined. It was demonstrated that Ch. reinhardtii is resistant to a wide range of concentrations of inorganic nitrogen and phosphorus compounds. Microalgae actively participate in the removal of N-NH4+ from wastewater (removal efficiency of 49-63%, depending on the initial concentration). At the same time, Ch. reinhardtii showed low levels of P-PO43- removal (7-18%) from the aquatic environment. O. neglecta, unlike Ch. reinhardtii, is sensitive to excessively high concentrations of N-NH4+ (90-140 mg l-1) and P-PO43- (26-90 mg l-1). However, it is characterized by high removal efficiency for both forms of nitrogen (60-61%) and phosphorus (43-55%) at their initial concentrations of 30-50 mg l-1 and 7-14 mg l-1, respectively. Therefore, O. neglecta is best suited for use in wastewater post-treatment.