Biomass production from microalgae Chlorella grown in sewage, kitchen wastewater using industrial CO2 emissions: Comparative study

Microalgae cultivation using organic wastewater like kitchen wastewater (KWW) and sewage wastewater (SWW) are recommended for wastewater treatment along with simultaneous biomass production which is a cost effective strategy. KWW is rich in nutrients which might be an efficient wastewater feedstock for microalgae cultivation to achieve reasonably high biomass yield for energy generation. KWW has not been investigated extensively for microalgae cultivation till now because of high concentration of ammonia as it could inhibit algae growth. In order to make KWW suitable for microalgae growth, a common method is to dilute with water. Hence, in the present study, KWW was diluted with water at dilution ration 1:1 and compared with SWW for microalgae biomass growth, biomass yields and nutrient removal efficiency specifically using Chlorella. Both KWW and SWW showed highest biomass productivity in mixotrophic cultivation mode. The average biomass productivity in SWW was 0.6 g/L which was higher when compared to KWW. Fourier infrared spectroscopy (FTIR) of algal biomass revealed the presence of certain organic compound groups such as -OH, -COOH, NH2, and =O. It was concluded from the results that Chlorella was very effective in the treatment of KWW, SWW and industrial flue gas on the other hand the biomass obtained is a sustainable green energy source for biofuels.