Semicontinuous Culture of Chlorella vulgaris Microalgae for Wastewater Treatment

The costs associated with wastewater treatment, as well as the huge amount of water to be processed, represent a major problem for today's society. In this study, the use of Chlorella vulgaris microalgae to carry out the purification process is analyzed. For that, three different types of wastewater have been tested. The obtained data show an organic matter removal up to 69%, as well as almost total phosphates elimination; both values were below the limits required by the European Commission Directive (98/15/EEC). In addition, different wastewater purifying cycles of 25%, 50%, 75%, 90% and 90% were conducted once nutrient levels dropped below those required by the regulations. Algal growth has been monitored by microalgae cell measurements and optical density, at 680 nm. Maximum growth of 15,805.56 +/- 432 cells/mL was reached at pH values within the interval 7.60 +/- 0.04 to 9.7 +/- 0.01 were registered throughout the growing cycle. A good adaptability of this microalgae was observed, as well as a good survival rate over time. [GRAPHICS] .