Combination of advanced biological systems and photocatalysis for the treatment of real hospital wastewater spiked with carbamazepine: A pilot-scale study

Over the past few decades, the increase in dependency on healthcare facilities has led to the generation of large quantities of hospital wastewater (HWW) rich in chemical oxygen demand (COD), total suspended solids (TSS), ammonia, recalcitrant pharmaceutically active compounds (PhACs), and other disease-causing microorganisms. Conventional treatment methods often cannot effectively remove the PhACs present in wastewater. Hence, hybrid processes comprising of biological treatment and advanced oxidation processes have been used recently to treat complex wastewater. The current study explores the performance of pilot-scale treatment of real HWW (3000 L/d) spiked with carbamazepine (CBZ) using combinations of moving and stationary bed bio-reactor-sedimentation tank (MBSST), aerated horizontal flow constructed wetland (AHFCW), and photocatalysis. The combination of MBSST and AHFCW could remove 85% COD, 93% TSS, 99% ammonia, and 30% CBZ. However, when the effluent of the AHFCW was subjected to photocatalysis, an enhanced CBZ removal of around 85% was observed. Furthermore, the intermediate products (IPs) formed after the photocatalysis was also less toxic than the IPs formed during the biological processes. The results of this study indicated that the developed pilot-scale treatment unit supplemented with photocatalysis could be used effectively to treat HWW.