Integrated assessment of sulfate-based AOPs for pharmaceutical active compound removal from wastewater

Advanced oxidation processes (AOPs) have been proposed as tertiary treatments for municipal WWTP effluents. UV-activated peroxydisulfate (PDS) and peroxymonosulfate (PMS) are viable technological alternatives for treating secondary WWTP effluent containing PhACs. This article examines the feasibility of applying UV/PDS and UV/PMS technologies at pilot scale, assessing their energy and cost requirements. In addition, life cycle assessment (LCA) impacts associated with the treatment of 1 m³ of wastewater with an effective average pharmaceutical active compounds (PhACs) removal of 80% has also been evaluated. Photolysis (UV) treatment alone was not capable of degrading PhACs to a sufficient extent in WWTP secondary effluent. The addition of 0.4 mmol of PDS or PMS, applying 416 mJ/cm2 of UV fluence, resulted in average removals of 84% and 85% for UV/PDS and UV/PMS, respectively. The electrical energy (kWh) required to degrade the mix of PhACs by one order of magnitude in 1 m³ of contaminated water was calculated as 0.9 kWh/m³/order and 0.8 kWh/m³/order 4 for UV/PDS and UV/PMS, respectively. However, the overall cost, including operation, materials and maintenance, of applying UV/PDS and UV/PMS, based on an average PhAC removal of 80%, was 0.088 €/m³ and 0.280 €/m³, respectively. From the sustainability assessment, the factors with the greatest environmental footprint for the UV/PDS process were chemical production (PDS: 52.9%, PMS: 85%) and electricity consumption (UV/PDS: 33.4%, UV/PMS: 11.2). Finally, the normalized environmental impact analysis showed that UV/PDS was associated with an environmental footprint three times lower than UV/PMS. The overall assessment revealed that UV/PDS is preferable to UV/PMS to remove PhACs in secondary effluents of municipal WWTPs having a lower economic and environmental impact.