Phosphorus removal in a pilot scale free water surface constructed wetland: hydraulic retention time, seasonality and standing stock evaluation. (March 2021)

• Record Type: Journal Article
• Authors: Baldovi, Aldrew Alencar; de Barros Aguiar, André Ribeiro; Benassi, Roseli Frederigi; Vymazal, Jan; de Jesus, Tatiane Araujo
• Is Part Of: Chemosphere. Volume 266(2021)
• Publication Date: 2021-03
• Subjects: Ecotechnology -- Harvesting -- Floating macrophyte -- Phosphorus recovery -- Wastewater; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128939
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Constructed wetlands (CWs) are decentralized wastewater treatment systems considered to be green and low cost. They have the potential to effectively remove pollutants and recycle nutrients with plant composting. However, they need large areas to implement them due to the usual high Hydraulic Retention Times (HRT), reaching up to 50 days. The main objective of the present study was to evaluate the influence of HRT (HRT = 3, 7, and 10 days), and seasonality on Total Phosphorus (TP) removal, and standing stock in a pilot scale free water surface CW (FWS CW). Unplanted and planted ( Eichhornia crassipes ) tanks were evaluated in wet and dry seasons. The FWS CW was set up as a complementary treatment to a secondary level wastewater treatment plant. The system was monitored weekly for ten months, totalizing 29 replicate samplings (n = 58). Planted tanks were harvested every week to keep free space for plant reproduction (∼40%). The mean removal efficiency of TP ranged between 82% and 95% without a significant difference between HRT (pvalue > 0.05). However, when the effects of the sedimentation of the unplanted tanks were disregarded, the lowest HRT (3 days) tank presented the highest standing stock of TP. The wet season presented a significant difference in TP removal results (pvalue < 0.05), associated with higher macrophyte growth rate due to more intense solar irradiation and incorporation of TP by E. crassipes . The results point out advances in P removal and recycling by a low-cost ecological engineering system. Graphical abstract: Image 1 Highlights: ∼90% of TP removal was achieved in a free water surface constructed wetland (FWSCW). 3 days HRT increased total phosphorus removal by Eichhornia crassipes . FWS CW with E. crassipes has a huge potential as tertiary wastewater treatment. The system has potential in P recycling by the biomass composting.