Performance evaluation of constructed wetland for removal of pharmaceutical compounds from hospital wastewater: Seasonal perspective

Constructed wetland employs vegetation as a natural medium to remove pollutants from wastewater for this treatment. It is eco-friendly, sustainable, economical, low maintenance, low run-ning cost, and easy to use. This has prompted several studies to investigate its performance in treat-ing pollutants from the conventional to emerging contaminants category, including pharmaceutical compounds. However, there is still a lack of work on the impact of monsoons on the removal effi-ciency of pharmaceutically active compounds from wastewater. This study evaluated constructed wetland performance during the premonsoon, monsoon, and post-monsoon seasons. A pilot -scale constructed wetland setup was established to conduct this study. The target compound included paracetamol, ibuprofen, carbamazepine, lorazepam, ciprofloxacin, sulfamethoxazole, and Fluvastatin. In the constructed wetland, for paracetamol and ibuprofen, NSAIDs concentra-tion was observed to be 1503-6307 ngL-1 and 564-808 ngL-1. The concentrations of antibiotics, sulfamethoxazole, and ciprofloxacin were 16532-21635 ngL-1 and 734-1178 ngL-1, respectively. The carbamazepine, lorazepam, and Lutvastatin concentration range was 616-906 ngL-1, 2742- 3775 ngL-1, and 694-2068 ngL-1, respectively. The hazard quotient approach was adopted to eval-uate potential environmental risk from target compounds. The increase of paracetamol 33 %, ibuprofen 94 %, ciprofloxacin 242 %, Sulfamethoxazole 64 %, and carbamazepine 77 % validated the study hypothesis. However, a decrease of 15 % lorazepam and 43 % Fluvastatin inferred that dilution was inversely proportional to the removal of these compounds. The seasonal removal effi-ciency was in order pre-monsoon < post-monsoon < monsoon. Hospital wastewater had HQ val-ues of 90, 100, and 130 for premonsoon, monsoon, and post-monsoon, respectively. After treatment from the constructed wetland, the wastewater effluent had reduced HQ value to 53, 35, and 70 for premonsoon, monsoon, and post-monsoon periods respectively. The HQ values were further reduced in tubesettler to 22, 11, and 28. Ciprofloxacin posed no significant risk. However, sul-famethoxazole posed a high risk during premonsoon, monsoon, and post-monsoon season. Further works are required to analyze the removal mechanism through plant uptake, sediment bed, and biodegradation for a different season or climatic condition to present the real-time performance of constructed wetlands for treating wastewater loaded with pharmaceutical compounds.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Constructed wetland utilizes vegetation as a natural medium to remove pollutants from wastewater. This study evaluates the performance of constructed wetland in different seasons and assesses the removal efficiency and environmental risk of pharmaceutical compounds. The results show that the seasonal variation and dilution effect influence the removal of these compounds, and further research is needed to understand the removal mechanisms in different climatic conditions.