The performance of the reactors was evaluated by systematic sampling every feeding cycle. Algal cell concentration was measured in the supernatant of the reactors after settling by a Neubauer haemocytometer (Aravantinou et al. 2015 (link)). Total suspended solids (TSS) and total solids (TS) were determined gravimetrically (APHA et al. 2012 ) in the supernatant and the mixed liquor. Soluble total phosphorous (sTotal-P) was measured by the persulfate method and ascorbic colorimetric technique (APHA et al. 2012 ). Nitrates (NO3-N) and phosphates (PO43--P) were measured by ion chromatography method (Metrohm 850 Professional IC, Metrohm Switzerland). Nitrates were also determined by a sodium salicylate method in the kinetic experiments to measure lower concentrations (Fresenius et al. 1988 ). Ammonia nitrogen (NH3-N) was measured in the supernatant by the trimetric method (APHA et al. 2012 ). Chlorophyll-a (Chl-a) was measured via a spectrophotometric method (APHA et al. 2012 ) in the supernatant and the mixed liquid. More details can be found in previous work (Biliani and Manariotis 2021 (link)).
The characteristics of biomass in the mixed liquid were also examined in terms of proteins, sugars, and lipids. Total lipids were extracted using the Folch method (Aravantinou et al. 2013 (link)). Total proteins were determined by the Lowry method (Lowry et al. 1951 (link)), while the biomass content in sugars was determined by the Dubois method (Dubois et al. 1956 (link)).
The characteristics of biomass in the mixed liquid were also examined in terms of proteins, sugars, and lipids. Total lipids were extracted using the Folch method (Aravantinou et al. 2013 (link)). Total proteins were determined by the Lowry method (Lowry et al. 1951 (link)), while the biomass content in sugars was determined by the Dubois method (Dubois et al. 1956 (link)).
