Nitrogen and phosphorus removal from plant nursery runoff in vegetated and unvegetated subsurface flow wetlands

• Published in: Water research (Oxford) Vol. 39; no. 14; pp. 3259 - 3272
• Main Authors: Huett, D.O., Morris, S.G., Smith, G., Hunt, N.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2005; Elsevier Science
• Subjects: agricultural runoff; Agriculture; Applied sciences; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; Constructed wetlands; Ecosystem; Environment and pollution; Exact sciences and technology; extraction; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Nitrate; nitrogen; Nitrogen - isolation & purification; Nitrogen - metabolism; Nursery runoff; nutrient uptake; Other industrial wastes. Sewage sludge; Phosphate; phosphorus; Phosphorus - isolation & purification; Phosphorus - metabolism; Phragmites australis; phytoremediation; plant growth; Poaceae - metabolism; Pollution; Reed bed; Subsurface-flow; Temperature; Time Factors; Waste Disposal, Fluid - methods; Wastes; Water Movements; Water Purification - methods; water treatment; Water treatment and pollution; wetlands; New South Wales; Australia; Oceania; Australia, New South Wales; Nursery runoff; Nitrate; Reed bed; Phragmites australis; Constructed wetlands; Phosphate; Subsurface-flow; Phosphates; Monocotyledones; Nitrates; Biological purification; Dissolved organic carbon; Batchwise; Gramineae; Angiospermae; Aquatic plant; Typha latifolia; Wetland; Phosphorus; Runoff water; Nitrogen; Typhaceae; Artificial medium; Surface water; Spermatophyta; Waste water purification
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2005.05.038

Subsurface horizontal flow reed beds are being evaluated for Nitrogen (N) and Phosphorus (P) removal from plant nursery runoff water in New South Wales Australia. The need to include plants ( Phragmites australis), the effect of reaction time (3.5 v 7.0 d) and dissolved organic carbon (DOC) on N and P removal in batch fed gravel wetland tubs (55 L) was studied over 19 months. Simulated nursery runoff water containing N (10.1 mg L −1, 74% as NO 3) and P (0.58 mg L −1, 88% as PO 4) and DOC (2–5 mg L −1) was used. The planted wetland tubs removed >96% TN and TP over most of the 19-month study period while unplanted tubs were inefficient (<16% N and <45% P removal) and occasionally discharged nutrients. Doubling the reaction time to 7.0 days had no effect on nutrient removal. Plant nutrient uptake accounted for most of the N (76%) and P (86%) removed while roots and rhizomes were the dominant sink (N 58%, P 67%). The addition of methanol (C:N–3:1) to unplanted tubs achieved 81–98% N removal. In Carbon limited low nutrient nursery runoff, plants were essential to a gravel-based wetland to achieve efficient nutrient removal with effluent TN and TP concentrations of <1 mg L −1 and 0.05 mg L −1, respectively with a 3.5 day reaction time.