Pigments in the algal biomass from aerobic waste water depuration ponds

A study of the algal pigments of the biomass from aerobic treatment ponds was made with the aim of supporting other procedures to identify the predominant species that grow in the experimental condition assayed. Chlorophillic and carotenoids pigments were separated and purified by TLC for later identification and quantification by HPLC. A significant predominance of fucoxanthin and diadinoxanthin which are specific of Diatoms were found, as well as very low proportions of other non-specific pigments from other minor growing species. The absence of chlorophyll ‘b’ and a low level of ‘c’ owing to a possible coexistence of Diatom and Cyanophyceae in the culture, must be emphasized. In the experimental conditions assayed the addition of silicates to the waste water promotes the growth of Diatoms specifically Fragilaria pinnata, and also induces the formation of a secondary microflora of Cyanophyceae type with bentonic characteristics, mainly Phormidium fragile, the principal characteristics of which, are a ready tendency to sedimentation and a large size, facilitating their separation by filtration or decantation.