Evaluate the effect of the dilution ratio on the growth and domestic wastewater treatment of Chlorella vulgaris

Abstract

The utilization of microalgae for wastewater treatment is gaining widespread recognition due to its numerous advantages and immense potential. Apart from wastewater treatment benefits, microalgal biomass can be valorized into environmentally friendly products, contributing to environmental protection and sustainable development. This study assessed the effect of the dilution ratio of domestic wastewater on the growth and the effectiveness of removing nitrogen, phosphorus, and COD in the wastewater of the Chlorella vulgaris microalgae strain on a laboratory scale. The experiment was arranged with the initial dilution ratio of 0.25 v/v; 0.5 v/v; 0.75 v/v, and 1.0 v/v. Growth parameters and factors such as N-NH₄⁺, N-NO₃^-, N-NO₂^-, T-P, P-PO₄^3- and COD have been collected during the experimental process. The experiments were conducted at an airflow rate of 1.2 L/L/min for 8 hours, with a rearing temperature of 20 - 22 ℃, and a light intensity of 5000 lux. Research results have shown that Chlorella vulgaris can grow in conditions of 100 % domestic wastewater at a ratio dilution of 1.0 v/v. Under these conditions, Chlorella vulgaris showed the best growth at 0.134 gSKK/L, with the highest removal efficiencies for N-NH₄⁺, T-P, P-PO₄^3- and COD reaching 85.22 %; 67,81 %, 74,10 % and 87,10 %, respectively.