Optimizing sewage treatment by UV/H2O2 process and vertical flow constructed wetland integration

Abstract

Wastewater treatments are challenged by the presence of organic pollutants, demanding efficient processes to maintain water quality. Constructed wetland (CW) systems offer a nature-based solution, standing out for their ability to remove pollutants and preserving terrestrial and aquatic ecosystems. Similarly, Advanced Oxidative Processes (AOPs) efficiently disinfect water and remove organic contaminants. Investigating integrated systems for wastewater treatment is crucial, not only for enhancing control parameters but also for enabling routine wastewater reuse. This study evaluates the efficacy of UV and UV/H2O2 AOPs in combination with a Vertical Flow Constructed Wetland (VF-CW) for organic matter removal from secondary effluent of a Wastewater Treatment Plant (WWTP). A Central Composite 22 experimental design was applied to optimize the studied variables, achieving removals up to 95 % for COD, 99 % for turbidity, and 96 % for UV254, with near-neutral pH, suggesting potential for effluent reuse. Furthermore, the combined system effectively eliminates toxicity to Artemia sp. and Lactuca sativa (TU ≤ 0.4) as well as microbiological parameters. The UV/H2O2 process and CWs are compatible, and their combination is an innovative and effective method that can be employed as a tertiary post-treatment method. Incorporating novel technological configurations for sewage and effluent treatment establish a NEXUS approach, fostering circular economy principles in wastewater management.