Kinetic of the Sewage Treatment: The Consumption of Organic Carbon of The Microalga Chlorella sp.

Abstract

As well known, microalgae are eukaryotic or procaryotic microorganisms able to photosynthesize, namely transforming inorganic substrates and sun light into organic compounds and chemical energy. They result very promising in treating civil wastewaters thanks to their ability to employ nitrates and phosphates as nutrients (Lima et al., 2019). Autotrophic microalgae are, anyway, not useful in decreasing the organic carbon content of wastewaters, and for this reason, they cooperate with heterotrophic bacteria. The usefulness of microalgae-bacteria consortia in treating wastewaters and the ratio of their inoculum was investigated in a previous work (Lima, 2022a). Contrarily to autotrophic microalgae, mixotrophic microalgae are able to decrease the organic content of the matrix in which they are grown. In this work, we preliminarily investigated the capability of the autochthonous microalga Chlorella sp. CW2 to grow in mixotrophy and decrease the organic content of the artificial wastewater in which they are grown. Several batch cultivations were performed with glucose in different concentrations. Kinetic parameters were obtained and employed to determine the dilution rate (D) ideal for the abatement of glucose from the artificial wastewater.