Comparison of aerated marsh-pond-marsh and continuous marsh constructed wetlands for treating swine wastewater

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Toxic/hazardous substances & environmental engineering, 2010-06, Vol.45 (7), p.803-809
• Main Authors: Forbes, Dean A, Reddy, G.B, Hunt, Patrick G, Poach, M.E, Ro, Kyoung S, Cyrus, Johnsely S
• Format: Article
• Language: English
• Subjects: Aerated; aeration; anaerobic conditions; animal manure management; Animals; autumn; chemical oxygen demand; Constructed wetlands; Construction; continuous marsh; cost effectiveness; Crack opening displacement; floods; Loading rate; marsh-pond-marsh design; marshes; Models, Theoretical; N removal; Nitrogen; Nitrogen - isolation & purification; phosphorus; pig manure; pollution load; Ponds; Reduction; Studies; summer; Swine; total solids; uptake mechanisms; Waste Disposal, Fluid - methods; waste lagoons; Waste water; wastewater treatment; Water pollution; Water Purification - methods; Water treatment; wetland plants; Wetlands
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934521003708927

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-1from 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.