Characterization of biomass pellets from Chlorella vulgaris microalgal production using industrial wastewater

Abstract

Industrial wastewater contains sources of nitrogen and phosphorus that tend to produce eutrophication in receiving water bodies when it has not been properly treated. Eutrophication is a type of chemical contamination of water that occurs when there is an excessive supply of nutrients to an aquatic ecosystem, It can occur naturally (red tides) but the anthropogenic emissions, as industrial and agricultural discharges, sewage from farms (dairies), urban waste and treatment plants that are the more common and hazardous. Microalgae are able to take advantage of the nutrients of these wastewaters and produce biomass. The objective of this study was to determine the potential energy of the algal biomass of Chlorella vulgaris using wastewater from a sugar industry and a dairy farm. Microalgae biomass was cultivated into a photobioreactor (PBR), processed, dried out in a solar drier for wood, compressed for the production of pellets and subsequent evaluation of the heating value and the physical-mechanical properties of the final product. The preliminary results showed that a higher heating value was observed in pellets using wastewater from dairy farm industry (1.23 ± 3.7) × 103kJ/100 g, compared to the caloric value of pellets made using algal biomass cultivated using wastewater from sugaring industry (0.73 ± 0.7) x 103kJ/100 g. The microalgae Chlorella vulgaris was cultivated in a chemical medium under laboratory conditions where an electronic device with Internet of Things (IoT) capabilities was used to measure ambient variables related to microalgae growing process.