HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Burchell, M. R. Articles by Osborne, J. Search for Related Content PubMed PubMed Citation Articles by Burchell, M. R., II Articles by Osborne, J. Agricola Articles by Burchell, M. R. Articles by Osborne, J. Related Collections Water Quality Wetland Soils

TECHNICAL REPORTS

Wetlands and Aquatic Processes

Substrate Organic Matter to Improve Nitrate Removal in Surface-Flow Constructed Wetlands

^a Dep. of Biological and Agric. Engineering, North Carolina State Univ., Box 7625, Raleigh, NC 27695-7625
^b Dep. of Biological and Agric. Engineering, North Carolina State Univ., Box 7625, Raleigh, NC 27695-7625
^c RSMT, 3919 Fisher Ferry Rd., Vicksburg, MS 39180
^d Dep. of Soil Science, North Carolina State Univ., Box 7619, Raleigh, NC 27695-7619
^e Dep. of Biological and Agric. Engineering, North Carolina State Univ., Box 7625, Raleigh, NC 27695-7625
^f Dep. of Statistics, North Carolina State Univ., Box 8203, Raleigh, NC 27695-8203

^* Corresponding author (mike_burchell{at}ncsu.edu)

Received for publication January 13, 2006. A wetland mesocosm experiment was conducted in eastern North Carolina to determine if organic matter (OM) addition to soils used for in-stream constructed wetlands would increase NO₃^––N treatment. Not all soils are suitable for wetland substrate, so OM addition can provide a carbon and nutrient source to the wetland early in its development to enhance denitrification and biomass growth. Four batch studies, with initial NO₃^––N concentrations ranging from 30 to 120 mg L^–1, were conducted in 2002 in 21 surface-flow wetland mesocosms. The results indicated that increasing the OM content of a Cape Fear loam soil from 50 g kg^–1 (5% dry wt.) to 110 g kg^–1 (11% dry wt.) enhanced NO₃^––N wetland treatment efficiency in spring and summer batch studies, but increases to 160 g kg^–1 (16% dry wt.) OM did not. Wetlands constructed with dredged material from the USACE Eagle Island Confined Disposal Facility in Wilmington, NC, with initial OM of 120 g kg^–1 (12% dry wt.), showed no improvement in NO₃^––N treatment efficiency when increased to 180 g kg^–1 (18% dry wt.), but did show increased NO₃^––N treatment efficiency in all batch studies when increased to 220 g kg^–1 (22% dry wt.). Increased OM addition and biosolids to the Cape Fear loam and dredged material blends significantly increased biomass growth in the second growing season when compared to no OM addition. Results of this research indicate that increased OM in the substrate will reduce the area required for in-stream constructed wetlands to treat drainage water in humid regions. It also serves as a demonstration of how dredged material can be used successfully in constructed wetlands, as an alternative to costly storage by the USACE.

Abbreviations: BOD, biological oxygen demand • CDF, confined disposal facility • DM, dredged material only treatment wetland • DMB18%, dredged material blend treatment wetland with 18% organic matter • DMB22%, dredged material blend treatment wetland with 22% organic matter • DMWs, dredge material wetlands • DO, dissolved oxygen • Eh, substrate redox • ET, evapotranspiration • OM, organic matter • RSMT, recycled soil manufacturing technology • SFCW, surface-flow constructed wetlands • SS, site soil only treatment wetland • SSB11%, site soil blend treatment wetland with 11% organic matter • SSB16%, site soil blend treatment wetland with 16% organic matter • SSWs, site soil wetlands