Phosphorus removal performance and biological dephosphorization process in treating reclaimed water by Integrated Vertical-flow Constructed Wetlands (IVCWs)

Phosphorous removal in adsorption had been extensively researched; however, the biological dephosphorization process and optimum operating parameters have not been discussed or quantified in Integrated Vertical-flow Constructed Wetlands (IVCWs). In this study, IVCWs planted with different plants were employed to evaluate total phosphorus (TP) treatment performance under different hydraulic retention times (HRTs), in summer and autumn. The results showed that the systems planted with Canna generalis showed the highest TP removal efficiency (77%) under a three-day HRT in autumn. The activities of exopolyphosphatase (PPX) and polyphosphate kinase (PPK) were determined, and it was found that PPK activity was seasonably variable and had been more active in autumn than that in summer (p < 0.05). Highly significant correlation was revealed between PPK activity and TP removal efficiency (p < 0.05). The 16S rDNA high-throughput sequencing results indicated that Pseudomonas genus might be the main participant in phosphorus aerobic biological adsorption in IVCWs. (C) 2017 Elsevier Ltd. All rights reserved.