The Absorption of Nitrate and Phosphate from Urban Sewage by Blue-Green Algae (Spirolina Platensis) (An Alternative Medium) as Application for Removing the Pollution

Abstract

The applications of blue green algae for the treatment of urban and industrial sewage have received more  attention during the recent years because they have the capacity to use nitrogenous compounds, ammonia and phosphates. In this study aimed to evaluate the ability of Spirolina platensis for absorption of nitrate and  phosphate from urban sewage. The experiment was conducted in 6 treatments as a growth medium. To test these predictions, we conducted a 15 days in indoor place under similar laboratory conditions at temperature (30ºC ± 2ºC), Light (2500 ± 500) Lux, pH between 8.0 and 11and with constant aeration. Regarding the culture media, a higher algal density was observed in the cultivation developed at treatment 5 (824 ±102 cell. mL-1). In our results showed higher efficiencies of phosphorus removal by S.platensis as compare to nitrate removal thus, S. platensis would be effective for nitrate removal only at relatively low concentrations and  phosphorus removal at high concentrations. Chlorophyll-a, content in treatment 3 was higher than other treatments. Kruscal-Wallis test showed a significant difference in treatments at the level of P<0.05. Thus, we recommend here that Spirolina platensis to be better candidate for absorption phosphate more than nitrate and it could be used for the removal or biotransformation urban sewage.

Keywords: Blue-Green Algae, Spirolina, Nitrate, Phosphate, Sewage, Pollution