Development of a Solar Energy-Based Prototype, CyanoClean, for Arsenic Removal from Groundwater Using Cyanobacterial Consortium

A cost-effective acrylic prototype, called CyanoClean, was developed for the growth of cyanobacterial consortium (Oscillatoria, Phormidium, and Gloeotrichia) and for removing arsenic (As) from water. The growth conditions for cyanobacterial growth were optimized by analyzing the increase in biomass (mg d⁻¹). The optimum conditions for cyanobacteria growth were pH, 7.6; initial cyanobacterial biomass, 10 g L⁻¹; arsenite [As(III)], 400 µΜ (30,000 µg L⁻¹); and arsenate [As(V)], 600 µM (45,000 µg L⁻¹). The concentration- and duration-dependent experiments were conducted in CyanoClean to examine the As removal potential of the consortium. The results demonstrated As removal to be in the range of 39–69% and 9–33%, respectively, from As(III) and As(V)-contaminated water. In the field testing of CyanoClean, a total of 150 g of the cyanobacterial consortium was used to treat 15 L of As-contaminated groundwater (102.43 µg As L⁻¹). Arsenic reduction was monitored at a flow rate of 3 L h⁻¹ for 15 h. In the field experiment, the cyanobacterial consortium reduced As concentration in groundwater from 102.43 to < 10 µg L⁻¹ at 7 h in natural sunlight while at 10 h in shaded conditions under artificial light. The CyanoClean prototype is a simple design that can be scaled up for application at a small- to medium-sized land of about one hectare.