Exploring the potential of wastewater reclamation by means of outdoor cultivation of microalgae in photobioreactors

In this article, through collected information and experimental analysis, effectiveness of microalgae cultivation was investigated as a mode of novel method of wastewater reclamation (WR). Domestic, agricultural and industrial sectors are the dominant sources of wastewater in the Asian region. In the Asian countries, about 75–100% of overall wastewater is disposed of untreated. Wastewater can be a potentially valuable resource after reclamation. But no effective practice of WR is reported in this region. The present method of WR worldwide faces barriers because of negative public perception. Microalgae cultivation in a photobioreactor (PBR) integrated with wastewater can be an innovative approach of WR, which is capable of addressing challenges of WR described in Hartley’s (Desalination 187(115):126. 10.1016/J.DESAL.2005.04.072, 2006) study. In experimental section of this study, Chlorella vulgaris and Chlorella ellipsoidea were cultivated in outdoor PBRs with domestic wastewater. Greywater medium provided 63–156% more productivity than of black water medium. The highest productivity of C. vulgaris and C. ellipsoidea was found 0.1472 and 0.1039 g/(L.d), respectively. Algal productivity was increased 1.37–1.70 times for pH control and 14% for reduction of light intensity. CO 2 supply showed a positive effect on C. vulgaris growth but decreased the productivity of C. ellipsoidea. In a tropical region like Thailand, light intensity should be controlled in outdoor to reduce photoinhibition, which can be carried out effectively with an adequately dimensioned roof. Successful experimentation of algal cultivation found in this study demonstrates the potential of microalgae cultivation in outdoor PBR for WR applications. Graphical abstract