Capability of Chlorella vulgaris to remove nitrate and phosphate at different concentrations and condition: studied by response surface methodology

In order to study the capability of microalgea Chlorella vulgaris in removal of nitrate and phosphate from water, the effects of initial concentration of nitrate and phosphate and photoperiod were investigated in 20 experiments proposed by response surface methodology. The most effective factors in nitrate removal include initial nitrate concentration, photoperiod and interaction of phosphate-photoperiod. Highest capability of nitrate removal (49.42%) achieved at the initial nitrate concentration of 1500 mg/l, initial phosphate concentration of 40 mg/l and under 16h of photoperiod. Initial concentration of phosphate, photoperiod and interaction of nitrate-phosphate and phosphate-photoperiod were the main factors affecting phosphate capability of algea.  Highest capability of nitrate removal (41.61%) achieved at the initial nitrate concentration of 2250 mg/l, initial phosphate concentration of 60 mg/l and under 24h of photoperiod.