Application of an innovative front aeration and internal recirculation strategy to improve the removal of pollutants in subsurface flow constructed wetlands

doi:10.1016/j.jenvman.2019.109873

CNU IR > College of Sustainable Environment and Recreation > Dept. of Environmental Resources Management > Periodical Articles > Item 310902800/34077

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Title:	Application of an innovative front aeration and internal recirculation strategy to improve the removal of pollutants in subsurface flow constructed wetlands
Authors:	Lin, Chien Jung Chyan, Jih Ming Zhuang, Wen Xue Vega, Floradelle Aboga Mendoza, Rose Marie O. Senoro, Delia B. Shiu, Ruei Feng Liao, Chih Hsiang Huang, Da Ji
Contributors:	Chia Nan Univ Pharm & Sci, Dept Environm Resources Management Adamson Univ, Dept Environm Sci & Engn Mapua Univ, Civil Engn & Environm Engn Univ Calif, Bioengn, Merced Camarines Norte State Coll Adamson Univ, Grad Sch Engn
Keywords:	Constructed wetlands Front aeration Internal recirculation Biochemical oxygen demand Ammonia-nitrogen Total nitrogen
Date:	2020
Issue Date:	2022-11-18 11:22:59 (UTC+8)
Publisher:	Academic Press Ltd- Elsevier Science Ltd
Abstract:	The pollutant removal performance of traditional horizontal subsurface flow (HSSF) constructed wetlands (CWs) is limited because of the dissolved oxygen (DO) supply is insufficient. The aeration of HSSF CWs usually improves their pollutant removal performance, but a high DO induces the accumulation of nitrate-nitrogen (NO3--N) and suppresses the improvement of total nitrogen (TN) removal. In this study, an integrated solution that involved in-tank front aeration and internal recirculation (FAIR) was used to improve the pollutant removal performance of HSSF CWs. Based on the experimental results, the FAIR system significantly increased the removal efficiencies of biochemical oxygen demand (BOD) from 53.8-76.0% to 82.0-91.7% and reduced the BOD concentration in the effluent to below 10 mg L-1. The removal efficiency of ammonia-nitrogen (NH3-N) increased from 15.1-78.3% to 98.5-98.6% while the removal efficiencies of the total Kjeldahl nitrogen (TKN) of the control and FAIR HSSF CWs were 18.2-77.1% and 93.5-94.3%, respectively. HSSF CWs with FAIR outperformed aerated HSSF CWs in the removal of NH3-N and TKN. The effects of two recirculation flow ratios (Rr = recirculation flow rate/influent flow rate), 14.3 and 3.0, on the improvement of pollutant removal performance were investigated. The lower Rr did not significantly affect the improvement of BOD, NH3-N, and TKN, but a higher Rr resulted in more severe accumulation of NO3--N. The removal efficiency of TN in control HSSF CWs ranged from 20.4% to 75.5%, and in the FAIR HSSF CW was 71.6% for Rr = 14.3 and 81.3% for Rr = 3.0. However, the FAIR system did not enhance the removal performance of total phosphorus, suggesting that the DO level and internal recirculation were not dominant mechanisms for the removal of phosphorous. The easy maintenance of the FAIR system made it a superior modification for improving the pollutant removal performance of HSSF CWs.
Relation:	Journal of Environmental Management, v.256, pp.9
Appears in Collections:	[Dept. of Environmental Resources Management] Periodical Articles

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