Response of Remediation Performances and Microbial Communities of Integrated Vertical-Flow Constructed Wetlands with Different Configurations after Chronic Exposure to Pharmaceuticals and Personal Care Products

Abstract

Integrated vertical-flow constructed wetlands (IVCWs) received increasing concern on their potential for pollutant elimination with high operational efforts, even for emerging contaminants such as pharmaceuticals and personal care products (PPCPs). However, it will be beneficial for the further reduction of input costs if the correlation between different construction strategies and corresponding removal performance can be clearly elucidated. Three IVCWs, named CW-A, CW-B, and CW-C, were constructed with different configurations in this study. The CW-A with artificial aeration and planting exhibited superior nitrogen removal performance (> 90%) over the other two systems, though along with increased input expenses. All types IVCWs showed satisfying removal performance of CODCr, MEA, and 2-php after maturity of CWs. The participation of planting Canna indica improved the elimination of SMX, evidenced by a higher removal efficiency of 92.42% in CW-A and 90.86 % in CW-B, compared to 69.58% in CW-C.Notably, results showed that the main pathway of PPCPs removal was biodegradation according to the mass balance. In all IVCWs, ammonia-oxidizing bacteria (AOB) were limited after exposure, while denitrifying bacteria still existed in high abundance. Findings from this work could provide informative references for the construction and maintenance of IVCWs with minimized expenses in practical applications while preserving excellent removal efficiencies of nitrogen and PPCPs.

Keywords: Integrated vertical-flow constructed wetlands, pharmaceuticals and personal care products, Artificial aeration, Microbial communities, Network analysis