title: Comparison of aerated marsh-pond-marsh and continuous marsh constructed wetlands for treating swine wastewater.
abstract: Increased swine production in North Carolina has resulted in greater waste generation and is demanding some emerging new innovative technologies to effectively treat swine wastewater. One of the cost-effective and passive methods to treat swine wastewater is using constructed wetlands. The objective of this study was to evaluate the N removal under two N loads in 3 different wetland systems: aerated marsh-pond-marsh (M-P-M), aerated marsh-covered pond-marsh (M-FB-M), and continuous marsh (CM) with two days drain and five days flood cycle. Swine wastewater from an anaerobic lagoon was applied to the constructed wetland cells (11 m wide x 40 m length) at two N loading rates of 7 and 12 kg N ha(-1) day(-1)from June to July and August to September 2005, respectively. Weekly inflow and outflow samples were collected for N, P, TS, and COD analysis. Total N reductions (%) at low and high N loading rates were 85.8 and 51.8; 86.3 and 63.3; and 86.2 and 61.8 for M-P-M, M-FB-M, and CM, respectively. Aeration had no significant (P > 0.05) impact on N removal. However, significant (P < 0.05) differences were observed for wetland systems between low and high N loading rates. No difference (P > 0.05) in N reduction was found among wetland systems. Vegetation uptake of N was negligible, ranging from 1.2 to 1.8 %. No significant (P > 0.05) differences in TS and COD removal were observed between the wetland systems.
authors.affiliation: Department of Natural Resources and Environmental Design, North Carolina A&T State University, Greensboro, North Carolina, USA.
authors.forename: Dean A
authors.initials: DA
authors.lastname: Forbes
authors.forename: G B
authors.initials: GB
authors.lastname: Reddy
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Hunt
authors.forename: M E
authors.initials: ME
authors.lastname: Poach
authors.forename: Kyoung S
authors.initials: KS
authors.lastname: Ro
authors.forename: Johnsely S
authors.initials: JS
authors.lastname: Cyrus
mesh_terms: D000818:Animals; D008962:Models, Theoretical; D009584:Nitrogen / Q000302:isolation & purification; D013552:Swine; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D053833:Wetlands
chemical_list: D009584:Nitrogen