An experimental constructed wetland system for the treatment of highway runoff in the UK

• Published in: Water science and technology 2001-01, Vol.44 (11-12), p.571-578
• Main Authors: SHUTES, R. B. E, REVITT, D. M, SCHOLES, L. N. L, FORSHAW, M, WINTER, B
• Format: Article
• Language: English
• Subjects: Applied sciences; Aquatic plants; Artificial wetlands; Biological and medical sciences; Biological treatment of waters; Biotechnology; British Isles; Cadmium; Chromium; Copper; Dieback; Ecosystem; Environment and pollution; Exact sciences and technology; Freshwater plants; Fundamental and applied biological sciences. Psychology; Geologic Sediments; Heavy metals; Highway construction; Industrial applications and implications. Economical aspects; Lead; Marshes; Metal concentrations; Metals, Heavy - analysis; Nickel; Nutrients; Other wastewaters; Phragmites australia; Phragmites australis; Poaceae - physiology; Pollution; Rain; Removal; Runoff; Storms; Typha latifolia; Uptake; Vehicle Emissions; Waste Disposal, Fluid - methods; Wastewaters; Water Movements; Water treatment and pollution; Wetlands; Zinc
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2001.0882

This paper compares the performance of an experimental highway runoff treatment system, incorporating a subsurface flow constructed wetland, with that of a vegetated balancing pond. Both systems are located on the same major road in the UK which opened in November 1998. Copper, chromium and nickel total aqueous metal concentrations, although low, have been consistently removed (maximum efficiencies of 67.3, 69.8 and 87.0% respectively in the constructed wetland), particularly in the summer. Zinc showed the highest aqueous metal concentrations and the generally positive removal by the constructed wetland system (maximum efficiency of 60.6%) correlates with the expected metal uptake by Typha latifolia and Phragmites australis. Sediment levels for these metals and for lead progressively decreased over the one year monitoring period. For the two storm events monitored in the constructed wetland system, all metals showed evidence of removal (removal efficiencies of 24.2 to 99.4%) except for copper. Lead and cadmium demonstrated the highest removal efficiencies followed by nickel and zinc. For both storms, the wetland acted as a source of copper (removal efficiencies of -88.4 to -97.1%), which may be explained by the die-back of aquatic plants and consequent release of organically bound copper.