Growth of microalgae adapted to high-light temperature conditions in different types of wastewater

Abstract

To obtain microalgae strains adapted to wastewater in the Mediterranean region, microalgae present in the Nile River were cultivated at both high-light temperature (HLT) and low-light temperature (LLT) conditions. It was found that the species which became dominant under HLT was chlorophyta of the genus Scenedesmus. In contrast, under LLT, bacillariophyta became dominant. The microalgae strain (Scenedesmus arcuatus) was subsequently isolated and cultivated in different types of primary treated wastewater under HLT and LLT conditions. The different types of primary treated wastewater were black water (BW), grey water (GW), and sewage water (SW). Growth rates reached during the exponential phase at HLT using GW, BW, and SW were between 0.38 and 0.4 (day−1). At LLT, 1.5–2.7 folds of lower growth rates were determined due to limitation by CO2. Removal of COD and inorganic N and P from sewage wastewater reached up to 88, 96, and 100%, respectively. Results thus indicate that microalgae adapted to the climate conditions can be efficiently used for COD removal and nutrient recovery from wastewater in the Mediterranean. HIGHLIGHTS Chlorophyta of the genus Scenedesmus are favourable to cultivation in the Mediterranean.; Domestic wastewaters allow high microalgae growth under HLT conditions and supply of CO2.; Removal of COD, and inorganic N and P under HLT from wastewater was up to 100%.; Up to 80% of the organic N present in the wastewater remained persistent.;

Keywords

• algal growth at high-light temperature conditions
• microalgae
• nutrient removal
• species isolation by dominance
• wastewater treatment