Nitrogen and phosphorus removal from urban wastewater for the microalgae Chorella sp. in conditions laboratory

Unialgal cultures of the microalga Chlorella sp. were used to evaluate its ability for nutri-ent removal from urban wastewater, collected from Stabilization Ponds System from the Uni-versidad del Zulia, Venezuela. The batch culture were initiated at a cell density of 2 x 10 super(6) cell/mL in 1200 mL of sterilized wastewater from ponds: facultative (B sub(1)), primary maturation (B sub(2)) and secondary maturation (B sub(3)), in relation to a control culture with commercial culture medium. The bioassays were maintained at a light intensity of 156 mu mol.q.m super(-2).s super(-1), light-dark cycle of 12:12h, 27 plus or minus 2 degree C y constant aeration. The water samples were taken from the cultures at times 0, 24, 48, 96 h and 22 days, were submit to N-NH super(+) sub(4) and P-PO super(-) sub(4) super(3) analyses. In wastewater cultures were obtained best growth of the microalga that in the control culture, reaching the highest cell density in B sub(1) with 19.24 plus or minus 0.93 x 10 super(6) cell/mL (p < 0.05). Highest chlorophyll and ca-rotenoids production was reached in B sub(1) with 2.292 plus or minus 0.516 and 1.805 plus or minus 0.211 mu g/mL, respectively. The total N-NH super(+) sub(4) removal was obtained between the days 2 and 4 for the wastewater cultures, meanwhile the P-PO super(-) sub(4) super(3) maximum removal at the end of the experiment, was reached in B1 with 73.5%. The microalga Chlorella sp., is a good alternative to reduce nitrogen and phosphorus loads from urban wastewater. Also, wastewaters can be used for mixotrophic production of microalgae.