Effects of hydraulic loading rate and organic load on the performance of a pilot-scale hybrid VF-HF constructed wetland in treating secondary effluent. (March 2019)

• Record Type: Journal Article
• Authors: Bang, Woo Hyuck; Jung, Yeonsung; Park, Ji Won; Lee, Seunghak; Maeng, Sung Kyu
• Is Part Of: Chemosphere. Volume 218(2019)
• Page Start: 232
• Page End: 240
• Publication Date: 2019-03
• Subjects: Bulk organic matter -- Fluorescence excitation-emission matrix -- Hybrid constructed wetlands -- Secondary effluent; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.11.110
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: This study evaluated the performance of a pilot-scale hybrid constructed wetland system for secondary effluent and investigated bulk organic matter characteristics. The hybrid constructed wetland consisted of a vertical-flow (VF) bed followed by a horizontal-flow (HF) bed. We also investigated the effects of hydraulic loading rates and influent organic load on the performance of the pilot-scale VF-HF hybrid constructed wetland. The results showed a high removal efficiency for suspended solids (>95%) and organic matter as determined by total organic carbon (>98.5%) and dissolved organic carbon (>70%), but no significant change in nitrogen removal was observed. The wetland treatment efficiency for suspended solids and organic matter showed a good buffer capacity even when hydraulic loading rates increased from 750 to 1500 L m −2 d −1 and 500–1000 L m −2 d −1 during the VF and HF stages, respectively. Moreover, there was no significant change in the performance when influent organic load increased eight-fold. Fluorescence excitation-emission matrix and liquid chromatography-organic carbon detection (LC-OCD) were used to investigate the dissolved organic matter characteristics in the hybrid VF-HF constructed wetland. Fluorescence excitation-emission matrix spectroscopy showed that both protein- and humic-like substances did not significantly change in the effluent when hydraulic loading rates and organic load increased by two- and eight-fold, respectively. Biopolymers determined using LC-OCD were effectively removed via the VF and HF stage wetlands, indicating the occurrence of biodegradation. Fluorescence excitation-emission matrix spectroscopy and LC-OCD provided the fate of dissolved organic matter characteristics in the hybrid VF-HF constructed wetland. Graphical abstract: Image 1 Highlights: A pilot scale hybrid VF-HF constructed wetland was used as tertiary treatment. VF constructed wetland preferentially removed biodegradable organic matter. Fluorescence EEM and LC-OCD are helpful to understand DOM characteristics.