Nutrients recovery and organic matter degradation from cropland wastewater by an optimized UV/H2O2 system

Abstract

In this research, nutrient recovery and organic matter removal from agricultural waste-water (AWW) were simultaneously evaluated through an advanced oxidation process (AOP). For this purpose, a 30 W/m2 UV/H2O2 system optimized regarding oxidant reagent dose and UV irradiation time was configured. The evaluated levels were 48.9, 65.3, and 84.6 Mm of hydrogen peroxide (H2O2) and 60, 90 and 120 min, respectively. Thus, through the response surface methodology (RSM) algorithm and the desirability function, it was found that it is possible to obtain efficiencies of 95 ± 5% in chemical oxygen demand (COD) removal and to generate 200 ± 11 % nitrates (NO3-N) and 100 ± 9.5 % of phosphates (PO4-P) with respect to the initial concentrations. Besides, the behavior of nitrogen and phosphorus chemical species was evaluated during the AWW treatment. The results suggest that the optimized UV/H2O2 system represents a technically feasible alternative for the efficient treatment of AWW. In fact, effluents with desirable characteristics for reuse in agriculture, such as high levels of nitrogen and phosphorus in chemical forms assimilable by crops were generated. Thus, this work contributes directly to solving problems related to water scarcity and fertilizer production.