On the operation of a solar photo-Fenton demonstration plant: Effect of microcontaminant removal rate on cost and environmental impact
E. Gualda-Alonso, D. Rodríguez-García, P. Soriano-Molina, Marta Pérez Martínez, Raquel Martínez-Vazquez, José Luis García Sánchez, J.L. Casas López, J.A. Sánchez Pérez
Abstract
• 100-m 2 RPR annual operation was simulated for solar photo-Fenton feasibility study. • 80 % CEC removal was the best target economically and sustainably vs 90 %. • Annual treatment cost was estimated to a competitive range of 0.23–0.32 € m −3 . • Every m 2 of photoreactor could cover water requirements of 1000-m 2 vegetable crops. This paper explores a techno-economic and environmental analysis of the solar photo-Fenton process for urban wastewater reclamation in operational environment at demonstration scale. For this purpose, the annual automatic operation of a 100-m 2 raceway pond reactor (RPR) was simulated using a robust kinetic model of the process at acidic pH, coupled with a data-based optimization approach used as a decision-making tool. Two treatment targets were set for the removal of contaminants of emerging concern (CECs): 80%, and 90%. The dynamic model was fed with local UVA irradiance data, RPR water temperature, the secondary effluent composition and power consumption. Simulation data were used to conduct the economic and life cycle assessments to compare the impact of each treatment target. The results show that removing 80% of the CECs offered a more economic-environmentally sustainable, and stable treatment performance than 90%. The annual-average optimal operating conditions to achieve this goal were: liquid depth of 16.5 ± 0.1 cm, hydraulic residence time of 33 ± 3 min, inlet reagent concentrations of 0.17 ± 0.03 mM for Fe 2+ and 0.47 ± 0.01 mM for H 2 O 2 with an annual-average treatment cost of 0.27 ± 0.03 € m −3 . The model projected a treatment capacity of 2.3 ± 0.7 m 3 m -2 day −1 , which translates to 1-m 2 RPR surface area could supply the daily-water requirement of at least 1,000 m 2 of greenhouse-grown vegetables. These findings could well contribute towards reducing the investment risk, promoting the commercial scale-up of the solar photo-Fenton process in the wastewater reclamation field.