Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

Sustainability

Pilar García-Jiménez¹  Marina Carrasco-Acosta¹  Ezio Ranieri²  JoséAlberto Herrera-Melián³  Rayco Alonso-Guedes³  Mónica Mendoza-Aguiar⁴ 

[1] Department of Biology, Institute of Environmental Studies and Natural Resources (i-UNAT), University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain;Department of Biology, University of Bari, 70125 Bari, Italy;Department of Chemistry, Institute of Environmental Studies and Natural Resources (i-UNAT), University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain;School of Civil and Industrial Engineering, University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain;

关键词: wastewater;    shallow constructed wetland;    horizontal flow;    substrate;    organic mulch;    gravel;   

DOI  :  10.3390/su12125102

来源: DOAJ

【 摘 要 】

In this study, pilot-scale hybrid constructed wetlands (CWs) and multistage horizontal subsurface flow CWs (HF CWs) have been studied and compared for the treatment of raw urban wastewater. In the hybrid CWs, the first stage was a mulch-based horizontal subsurface flow CW and the second stage was a vertical subsurface flow CW (VF CW). The VF CWs were used to determine if sand could improve the performance of the hybrid CW with respect to the mulch. In the multistage HFs, mulch, gravel and sand were used as substrates. The effect of water height (HF10: 10 cm vs. HF40: 40 cm) and surface loading rate (SLR: 12 vs. 24 g Chemical Oxygen Demand (COD)/m²d) has been studied. The results show that the use of sand in the vertical flow stage of the hybrid CW did not improve the average performance. Additionally, the sand became clogged, while the mulch did not. The effect of water height on average pollutant removal was not determined but HF10 performed better regarding compliance with legal regulations. With a SLR of 12 g COD/m²d, removals of HF10 were: 79% for COD, 75% for NH₄⁺-N, 53% for dissolved molybdate-reactive phosphate-P (DRP), 99% for turbidity and 99.998% for E. coli and total coliforms. When SLR was doubled, removals decreased for NH₄⁺-N: 49%, DRP: −20%, E coli and total coliforms: 99.5–99.9%, but not for COD (85%) and turbidity (99%). Considering the obtained results and the simplicity of the construction and operation of HFs, HF10 would be the most suitable choice for the treatment of raw urban wastewater without clogging problems.

【 授权许可】

Unknown