Benzene removal with vertical-flow constructed treatment wetlands

• Published in: Journal of chemical technology and biotechnology (1986) Vol. 83; no. 1; pp. 55 - 63
• Main Authors: Eke, Paul E, Scholz, Miklas
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 2008; Wiley
• Subjects: aggregate; Applied sciences; biodegradation; Biological and medical sciences; Biotechnology; Chemical engineering; constructed treatment wetland; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General purification processes; hydrocarbon; Methods. Procedures. Technologies; Others; Phragmites australis; Pollution; Various methods and equipments; volatilization; Wastewaters; Water treatment and pollution; Biodegradation; Vertical flow; Phragmites australis; constructed treatment wetland; Retention; hydrocarbon; Petroleum; Waste water; Biological purification; Pollution; Batchwise; Pumping; Chemical oxygen demand; Artificial medium; Volatilization; Redox potential; Aggregate; Dissolved oxygen; Wetland
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.1778

BACKGROUND: Twelve vertical-flow experimental wetlands have been constructed using different compositions, and were operated in batch-flow mode to reduce pumping costs. Six wetlands were located indoors and six outdoors. Benzene was used as a representative example substance to assess the removal of low molecular weight petroleum compounds.RESULTS: Findings indicate that the constructed wetlands remove benzene (inflow of approximately 1.3 g L⁻¹) from hydrocarbon-contaminated wastewater streams with better indoor (controlled environment) than outdoor treatment performances. Overall mean removal efficiencies for the experimental rig placed outside were as follows: benzene 85%, chemical oxygen demand (COD), 70%; ammonia-nitrogen, 83%; nitrate-nitrogen, 88%; ortho-phosphate-phosphorus, 58%. In comparison, removal efficiencies for the experimental rig placed indoors were higher: benzene 95%, COD, 80%; ammonia-nitrogen, 90%; nitrate-nitrogen, 94%; ortho-phosphate-phosphorus, 66%. Benzene removal was predominantly due to volatilization after 1 day of retention time.CONCLUSION: The use of aggregates (sand and gravel) and the presence of Phragmites australis (Cav.) Trin. ex Steud. resulted in no significant difference in terms of benzene, redox potential, dissolved oxygen, 5-day at 20 °C N-allylthiourea biochemical oxygen demand, COD and nutrients removal. Statistical differences were assessed by analysis of variance and Tukey HSD tests (P < 0.05). Copyright © 2007 Society of Chemical Industry